source: opengl-game/new-game.cpp@ 646f3f2

#include "logger.h"

#include "stb_image.h"

// I think this was for the OpenGL 4 book font file tutorial
//#define STB_IMAGE_WRITE_IMPLEMENTATION
//#include "stb_image_write.h"

#define _USE_MATH_DEFINES

#include <glm/mat4x4.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

#include "IMGUI/imgui.h"
#include "imgui_impl_glfw_gl3.h"

#include <GL/glew.h>
#include <GLFW/glfw3.h>

#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <fstream>
#include <sstream>
#include <cmath>
#include <string>
#include <array>
#include <vector>
#include <queue>
#include <map>

using namespace std;
using namespace glm;

enum State {
   STATE_MAIN_MENU,
   STATE_GAME,
};

enum Event {
   EVENT_GO_TO_MAIN_MENU,
   EVENT_GO_TO_GAME,
   EVENT_QUIT,
};

enum ObjectType {
   TYPE_SHIP,
   TYPE_ASTEROID,
   TYPE_LASER,
   TYPE_EXPLOSION,
};

struct SceneObject {
   unsigned int id;
   ObjectType type;

   // Currently, model_transform should only have translate, and rotation and scale need to be done in model_base since
   // they need to be done when the object is at the origin. I should change this to have separate scale, rotate, and translate
   // matrices for each object that can be updated independently and then applied to the object in that order.
   mat4 model_mat, model_base, model_transform;
   mat4 translate_mat; // beginning of doing what's mentioned above
   GLuint shader_program;
   unsigned int num_points;
   GLuint vertex_vbo_offset;
   GLuint ubo_offset;
   vector<GLfloat> points;
   vector<GLfloat> colors;
   vector<GLfloat> texcoords;
   vector<GLfloat> normals;
   vector<GLfloat> selected_colors;
   bool deleted;
   vec3 bounding_center;
   GLfloat bounding_radius;
};

struct Asteroid : SceneObject {
   float hp;
};

struct Laser : SceneObject {
   Asteroid* targetAsteroid;
};

struct EffectOverTime {
   float& effectedValue;
   float startValue;
   double startTime;
   float changePerSecond;
   bool deleted;
   SceneObject* effectedObject;

   EffectOverTime(float& effectedValue, float changePerSecond, SceneObject* object)
      : effectedValue(effectedValue), changePerSecond(changePerSecond), effectedObject(object) {
      startValue = effectedValue;
      startTime = glfwGetTime();
      deleted = false;
   }
};

struct BufferInfo {
   unsigned int vbo_base;
   unsigned int vbo_offset;
   unsigned int vbo_capacity;
   unsigned int ubo_base;
   unsigned int ubo_offset;
   unsigned int ubo_capacity;
};

void glfw_error_callback(int error, const char* description);

void mouse_button_callback(GLFWwindow* window, int button, int action, int mods);
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods);

void APIENTRY debugGlCallback(
   GLenum source,
   GLenum type,
   GLuint id,
   GLenum severity,
   GLsizei length,
   const GLchar* message,
   const void* userParam
);

bool faceClicked(array<vec3, 3> points, SceneObject* obj, vec4 world_ray, vec4 cam, vec4& click_point);
bool insideTriangle(vec3 p, array<vec3, 3> triangle_points);

GLuint loadShader(GLenum type, string file);
GLuint loadShaderProgram(string vertexShaderPath, string fragmentShaderPath);
unsigned char* loadImage(string file_name, int* x, int* y);

void printVector(string label, vec3& v);
void print4DVector(string label, vec4& v);

void initObject(SceneObject* obj);
void addObjectToScene(SceneObject* obj,
                  map<GLuint, BufferInfo>& shaderBufferInfo,
                  GLuint points_vbo,
                  GLuint colors_vbo,
                  GLuint selected_colors_vbo,
                  GLuint texcoords_vbo,
                  GLuint normals_vbo,
                  GLuint ubo,
                  GLuint model_mat_idx_vbo,
                  GLuint asteroid_sp);
void removeObjectFromScene(SceneObject& obj, GLuint ubo);

void calculateObjectBoundingBox(SceneObject* obj);

void initializeBuffers(
                  GLuint* points_vbo,
                  GLuint* colors_vbo,
                  GLuint* selected_colors_vbo,
                  GLuint* texcoords_vbo,
                  GLuint* normals_vbo,
                  GLuint* ubo,
                  GLuint* model_mat_idx_vbo);

GLuint initializeParticleEffectBuffers(vec3 origin, mat4 proj, mat4 view, GLuint explosion_sp,
                  map<GLuint, BufferInfo>& shaderBufferInfo,
                  GLuint points_vbo,
                  GLuint colors_vbo,
                  GLuint selected_colors_vbo,
                  GLuint texcoords_vbo,
                  GLuint normals_vbo,
                  GLuint ubo,
                  GLuint model_mat_idx_vbo);

void populateBuffers(vector<SceneObject*>& objects,
                  map<GLuint, BufferInfo>& shaderBufferInfo,
                  GLuint points_vbo,
                  GLuint colors_vbo,
                  GLuint selected_colors_vbo,
                  GLuint texcoords_vbo,
                  GLuint normals_vbo,
                  GLuint ubo,
                  GLuint model_mat_idx_vbo,
                  GLuint asteroid_sp);

void copyObjectDataToBuffers(SceneObject& obj,
                  map<GLuint, BufferInfo>& shaderBufferInfo,
                  GLuint points_vbo,
                  GLuint colors_vbo,
                  GLuint selected_colors_vbo,
                  GLuint texcoords_vbo,
                  GLuint normals_vbo,
                  GLuint ubo,
                  GLuint model_mat_idx_vbo,
                  GLuint asteroid_sp);

void transformObject(SceneObject& obj, const mat4& transform, GLuint ubo);

// TODO: instead of using these methods, create constructors for these
SceneObject* createShip(GLuint shader);
Asteroid* createAsteroid(vec3 pos, GLuint shader);
Laser* createLaser(vec3 start, vec3 end, vec3 color, GLfloat width, GLuint laser_sp);
SceneObject* createExplosion(GLuint shader);

void translateLaser(Laser* laser, const vec3& translation, GLuint ubo);
void updateLaserTarget(Laser* laser, vector<SceneObject*>& objects, GLuint points_vbo, GLuint asteroid_sp);
bool getLaserAndAsteroidIntersection(vec3& start, vec3& end, SceneObject& asteroid, vec3& intersection);

void renderMainMenu();
void renderMainMenuGui();

void renderScene(map<GLuint, BufferInfo>& shaderBufferInfo,
                  GLuint color_sp, GLuint asteroid_sp, GLuint texture_sp, GLuint laser_sp, GLuint explosion_sp,
                  GLuint color_vao, GLuint asteroid_vao, GLuint texture_vao, GLuint laser_vao, GLuint explosion_vao,
                  GLuint colors_vbo, GLuint selected_colors_vbo, GLuint ubo,
                  SceneObject* selectedObject);

void renderSceneGui();

float getRandomNum(float low, float high);

#define NUM_KEYS (512)
#define ONE_DEG_IN_RAD ((2.0f * M_PI) / 360.0f) // 0.017444444 (maybe make this a const instead)
#define TARGET_FPS 60.0f

const int KEY_STATE_UNCHANGED = -1;
const bool FULLSCREEN = false;
const int EXPLOSION_PARTICLE_COUNT = 300;
unsigned int MAX_UNIFORMS = 0; // Requires OpenGL constants only available at runtime, so it can't be const

int key_state[NUM_KEYS];
bool key_down[NUM_KEYS];

int width = 640;
int height = 480;

double fps;
unsigned int score = 0;

vec3 cam_pos;

mat4 view_mat;
mat4 proj_mat;

vector<SceneObject*> objects;
queue<Event> events;
vector<EffectOverTime*> effects;

SceneObject* clickedObject = NULL;
SceneObject* selectedObject = NULL;

float NEAR_CLIP = 0.1f;
float FAR_CLIP = 100.0f;

// TODO: Should really have some array or struct of UI-related variables
bool isRunning = true;

ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

Laser* leftLaser = NULL;
EffectOverTime* leftLaserEffect = NULL;

Laser* rightLaser = NULL;
EffectOverTime* rightLaserEffect = NULL;

SceneObject* objExplosion;
SceneObject* objFirst;

/*
* TODO: Asteroid and ship movement currently depend on framerate, fix this in a generic/reusable way
* Disabling vsync is a great way to test this
*/

int main(int argc, char* argv[]) {
   cout << "New OpenGL Game" << endl;

   if (!restart_gl_log()) {}
   gl_log("starting GLFW\n%s\n", glfwGetVersionString());

   glfwSetErrorCallback(glfw_error_callback);
   if (!glfwInit()) {
      fprintf(stderr, "ERROR: could not start GLFW3\n");
      return 1;
   }

#ifdef __APPLE__
   glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
   glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
   glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
   glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
#else
   glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
   glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
#endif

   GLFWwindow* window = NULL;
   GLFWmonitor* mon = NULL;

   glfwWindowHint(GLFW_SAMPLES, 16);
   glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, true);

   if (FULLSCREEN) {
      mon = glfwGetPrimaryMonitor();
      const GLFWvidmode* vmode = glfwGetVideoMode(mon);

      width = vmode->width;
      height = vmode->height;
      cout << "Fullscreen resolution " << vmode->width << "x" << vmode->height << endl;
   }
   window = glfwCreateWindow(width, height, "New OpenGL Game", mon, NULL);

   if (!window) {
      fprintf(stderr, "ERROR: could not open window with GLFW3\n");
      glfwTerminate();
      return 1;
   }

   glfwMakeContextCurrent(window);
   glewExperimental = GL_TRUE;
   glewInit();

   if (GLEW_KHR_debug) {
      cout << "FOUND GLEW debug extension" << endl;
      glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS);
      glDebugMessageCallback((GLDEBUGPROC)debugGlCallback, nullptr);
      cout << "Bound debug callback" << endl;
   } else {
     cout << "OpenGL debugg message callback is not supported" << endl;
   }

   srand(time(0));

   /*
   * RENDERING ALGORITHM NOTES:
   *
   * Basically, I need to split my objects into groups, so that each group fits into
   * GL_MAX_UNIFORM_BLOCK_SIZE. I need to have an offset and a size for each group.
   * Getting the offset is straitforward. The size may as well be GL_MAX_UNIFORM_BLOCK_SIZE
   * for each group, since it seems that smaller sizes just round up to the nearest GL_MAX_UNIFORM_BLOCK_SIZE
   *
   * I'll need to have a loop inside my render loop that calls glBindBufferRange(GL_UNIFORM_BUFFER, ...
   * for every 1024 objects and then draws all those objects with one glDraw call.
   *
   * Since I currently have very few objects, I'll wait to implement this  until I have
   * a reasonable number of objects always using the same shader.
   */

   GLint UNIFORM_BUFFER_OFFSET_ALIGNMENT, MAX_UNIFORM_BLOCK_SIZE;
   glGetIntegerv(GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT, &UNIFORM_BUFFER_OFFSET_ALIGNMENT);
   glGetIntegerv(GL_MAX_UNIFORM_BLOCK_SIZE, &MAX_UNIFORM_BLOCK_SIZE);

   MAX_UNIFORMS = MAX_UNIFORM_BLOCK_SIZE / sizeof(mat4);

   cout << "UNIFORM_BUFFER_OFFSET_ALIGNMENT: " << UNIFORM_BUFFER_OFFSET_ALIGNMENT << endl;
   cout << "MAX_UNIFORMS: " << MAX_UNIFORMS << endl;

   // Setup Dear ImGui binding
   IMGUI_CHECKVERSION();
   ImGui::CreateContext();
   ImGuiIO& io = ImGui::GetIO(); (void)io;
   //io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
   //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;   // Enable Gamepad Controls
   ImGui_ImplGlfwGL3_Init(window, true);

   // Setup style
   ImGui::StyleColorsDark();
   //ImGui::StyleColorsClassic();

   glfwSetMouseButtonCallback(window, mouse_button_callback);
   glfwSetKeyCallback(window, key_callback);

   const GLubyte* renderer = glGetString(GL_RENDERER);
   const GLubyte* version = glGetString(GL_VERSION);
   cout << "Renderer: " << renderer << endl;
   cout << "OpenGL version supported " << version << endl;

   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

   glEnable(GL_DEPTH_TEST);
   glDepthFunc(GL_LESS);

   glEnable(GL_CULL_FACE);
   // glCullFace(GL_BACK);
   // glFrontFace(GL_CW);

   /*
   int x, y;
   unsigned char* texImage = loadImage("test.png", &x, &y);
   if (texImage) {
     cout << "Yay, I loaded an image!" << endl;
     cout << x << endl;
     cout << y << endl;
     printf("first 4 bytes are: %i %i %i %i\n", texImage[0], texImage[1], texImage[2], texImage[3]);
   }

   GLuint testTex = 0;
   glGenTextures(1, &testTex);
   glActiveTexture(GL_TEXTURE0);
   glBindTexture(GL_TEXTURE_2D, testTex);
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, x, y, 0, GL_RGBA, GL_UNSIGNED_BYTE, texImage);

   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   */

   int x, y;
   unsigned char* texImage = loadImage("laser.png", &x, &y);
   if (texImage) {
      cout << "Laser texture loaded successfully!" << endl;
      cout << x << endl;
      cout << y << endl;
      printf("first 4 bytes are: %i %i %i %i\n", texImage[0], texImage[1], texImage[2], texImage[3]);
   }

   GLuint laserTex = 0;
   glGenTextures(1, &laserTex);
   glActiveTexture(GL_TEXTURE0);
   glBindTexture(GL_TEXTURE_2D, laserTex);
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, x, y, 0, GL_RGBA, GL_UNSIGNED_BYTE, texImage);

   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

   /* RENDERING ALGORITHM
    * 
    * Create a separate vbo for each of the following things:
    * - points
    * - colors
    * - texture coordinates
    * - selected colors
    * - normals
    * - indices into a ubo that stores a model matrix for each object
    *
    * Also, make a model matrix ubo, the entirety of which will be passed to the vertex shader.
    * The vbo containing the correct index into the ubo (mentioned above) will be used to select
    * the right model matrix for each point. The index in the vbo will be the saem for all points
    * of any given object.
    *
    * There will be two shader programs for now, one for draing colored objects, and another for
    * drawing textured ones. The points, normals, and model mat ubo indices will be passed to both
    * shaders, while the colors vbo will only be passed to the colors shader, and the texcoords vbo
    * only to the texture shader.
    *
    * Right now, the currently selected object is drawn using one color (specified in the selected
    * colors vbo) regardless of whether it is normally rendering using colors or a texture. The selected
    * object is rendering by binding the selected colors vbo in place of the colors vbo and using the colors
    * shader. Then, the selected object is redrawn along with all other objects, but the depth buffer test
    * prevents the unselected version of the object from appearing on the screen. This lets me render all the
    * objects that use a particular shader using one glDrawArrays() call.
    */

   map<GLuint, BufferInfo> shaderBufferInfo;

   // TODO: Rename color_sp to ship_sp and comment out texture_sp)

   GLuint color_sp = loadShaderProgram("./ship.vert", "./ship.frag");
   GLuint asteroid_sp = loadShaderProgram("./asteroid.vert", "./asteroid.frag");
   GLuint texture_sp = loadShaderProgram("./texture.vert", "./texture.frag");
   GLuint laser_sp = loadShaderProgram("./laser.vert", "./laser.frag");
   GLuint explosion_sp = loadShaderProgram("./explosion.vert", "./explosion.frag");

   shaderBufferInfo[color_sp] = BufferInfo();
   shaderBufferInfo[asteroid_sp] = BufferInfo();
   shaderBufferInfo[texture_sp] = BufferInfo();
   shaderBufferInfo[laser_sp] = BufferInfo();
   shaderBufferInfo[explosion_sp] = BufferInfo();

   cam_pos = vec3(0.0f, 0.0f, 2.0f);
   float cam_yaw = 0.0f * 2.0f * 3.14159f / 360.0f;
   float cam_pitch = -50.0f * 2.0f * 3.14159f / 360.0f;

   // player ship
   SceneObject* ship = createShip(color_sp);
   objects.push_back(ship);

   vector<SceneObject>::iterator obj_it;

   GLuint points_vbo, colors_vbo, selected_colors_vbo, texcoords_vbo,
      normals_vbo, ubo, model_mat_idx_vbo;

   initializeBuffers(
      &points_vbo,
      &colors_vbo,
      &selected_colors_vbo,
      &texcoords_vbo,
      &normals_vbo,
      &ubo,
      &model_mat_idx_vbo);

   populateBuffers(objects,
      shaderBufferInfo,
      points_vbo,
      colors_vbo,
      selected_colors_vbo,
      texcoords_vbo,
      normals_vbo,
      ubo,
      model_mat_idx_vbo,
      asteroid_sp);

   GLuint color_vao = 0;
   glGenVertexArrays(1, &color_vao);
   glBindVertexArray(color_vao);

   glEnableVertexAttribArray(0);
   glEnableVertexAttribArray(1);
   glEnableVertexAttribArray(2);
   glEnableVertexAttribArray(3);

   glBindBuffer(GL_ARRAY_BUFFER, points_vbo);
   glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   // Comment these two lines out when I want to use selected colors
   glBindBuffer(GL_ARRAY_BUFFER, colors_vbo);
   glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, normals_vbo);
   glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, model_mat_idx_vbo);
   glVertexAttribIPointer(3, 1, GL_UNSIGNED_INT, 0, NULL);

   GLuint asteroid_vao = 0;
   glGenVertexArrays(1, &asteroid_vao);
   glBindVertexArray(asteroid_vao);

   glEnableVertexAttribArray(0);
   glEnableVertexAttribArray(1);
   glEnableVertexAttribArray(2);
   glEnableVertexAttribArray(3);

   glBindBuffer(GL_ARRAY_BUFFER, points_vbo);
   glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, colors_vbo);
   glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, normals_vbo);
   glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, model_mat_idx_vbo);
   glVertexAttribIPointer(3, 1, GL_UNSIGNED_INT, 0, NULL);

   GLuint texture_vao = 0;
   glGenVertexArrays(1, &texture_vao);
   glBindVertexArray(texture_vao);

   glEnableVertexAttribArray(0);
   glEnableVertexAttribArray(1);
   glEnableVertexAttribArray(2);
   glEnableVertexAttribArray(3);

   glBindBuffer(GL_ARRAY_BUFFER, points_vbo);
   glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, texcoords_vbo);
   glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, normals_vbo);
   glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, model_mat_idx_vbo);
   glVertexAttribIPointer(3, 1, GL_UNSIGNED_INT, 0, NULL);

   GLuint laser_vao = 0;
   glGenVertexArrays(1, &laser_vao);
   glBindVertexArray(laser_vao);

   glEnableVertexAttribArray(0);
   glEnableVertexAttribArray(1);
   glEnableVertexAttribArray(2);

   glBindBuffer(GL_ARRAY_BUFFER, points_vbo);
   glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, texcoords_vbo);
   glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, model_mat_idx_vbo);
   glVertexAttribIPointer(2, 1, GL_UNSIGNED_INT, 0, NULL);

   float cam_speed = 1.0f;
   float cam_yaw_speed = 60.0f*ONE_DEG_IN_RAD;
   float cam_pitch_speed = 60.0f*ONE_DEG_IN_RAD;

   // glm::lookAt can create the view matrix
   // glm::perspective can create the projection matrix

   mat4 T = translate(mat4(1.0f), vec3(-cam_pos.x, -cam_pos.y, -cam_pos.z));
   mat4 yaw_mat = rotate(mat4(1.0f), -cam_yaw, vec3(0.0f, 1.0f, 0.0f));
   mat4 pitch_mat = rotate(mat4(1.0f), -cam_pitch, vec3(1.0f, 0.0f, 0.0f));
   mat4 R = pitch_mat * yaw_mat;
   view_mat = R*T;

   // TODO: Create a function to construct the projection matrix
   // (Maybe I should just use glm::perspective, after making sure it matches what I have now)
   float fov = 67.0f * ONE_DEG_IN_RAD;
   float aspect = (float)width / (float)height;

   float range = tan(fov * 0.5f) * NEAR_CLIP;
   float Sx = NEAR_CLIP / (range * aspect);
   float Sy = NEAR_CLIP / range;
   float Sz = -(FAR_CLIP + NEAR_CLIP) / (FAR_CLIP - NEAR_CLIP);
   float Pz = -(2.0f * FAR_CLIP * NEAR_CLIP) / (FAR_CLIP - NEAR_CLIP);

   float proj_arr[] = {
     Sx, 0.0f, 0.0f, 0.0f,
     0.0f, Sy, 0.0f, 0.0f,
     0.0f, 0.0f, Sz, -1.0f,
     0.0f, 0.0f, Pz, 0.0f,
   };
   proj_mat = make_mat4(proj_arr);

   GLuint explosion_vao = initializeParticleEffectBuffers(vec3(0.0f, -1.2f, 0.65f), proj_mat, view_mat,
      explosion_sp,
      shaderBufferInfo,
      points_vbo,
      colors_vbo,
      selected_colors_vbo,
      texcoords_vbo,
      normals_vbo,
      ubo,
      model_mat_idx_vbo);

   GLuint ub_binding_point = 0;

   // TODO: Replace test_loc and mat_loc with more descriptive names
   GLuint view_test_loc = glGetUniformLocation(color_sp, "view");
   GLuint proj_test_loc = glGetUniformLocation(color_sp, "proj");
   GLuint color_sp_models_ub_index = glGetUniformBlockIndex(color_sp, "models");

   GLuint asteroid_view_mat_loc = glGetUniformLocation(asteroid_sp, "view");
   GLuint asteroid_proj_mat_loc = glGetUniformLocation(asteroid_sp, "proj");
   GLuint asteroid_sp_models_ub_index = glGetUniformBlockIndex(asteroid_sp, "models");

   GLuint view_mat_loc = glGetUniformLocation(texture_sp, "view");
   GLuint proj_mat_loc = glGetUniformLocation(texture_sp, "proj");
   GLuint texture_sp_models_ub_index = glGetUniformBlockIndex(texture_sp, "models");

   GLuint laser_view_mat_loc = glGetUniformLocation(laser_sp, "view");
   GLuint laser_proj_mat_loc = glGetUniformLocation(laser_sp, "proj");
   GLuint laser_color_loc = glGetUniformLocation(laser_sp, "laser_color");
   GLuint laser_sp_models_ub_index = glGetUniformBlockIndex(laser_sp, "models");

   GLuint explosion_start_time_loc = glGetUniformLocation(explosion_sp, "explosion_start_time");
   GLuint cur_time_loc = glGetUniformLocation(explosion_sp, "cur_time");
   GLuint explosion_sp_models_ub_index = glGetUniformBlockIndex(explosion_sp, "models");


   glUseProgram(color_sp);
   glUniformMatrix4fv(view_test_loc, 1, GL_FALSE, value_ptr(view_mat));
   glUniformMatrix4fv(proj_test_loc, 1, GL_FALSE, value_ptr(proj_mat));

   glUniformBlockBinding(color_sp, color_sp_models_ub_index, ub_binding_point);
   glBindBufferRange(GL_UNIFORM_BUFFER, ub_binding_point, ubo, 0, GL_MAX_UNIFORM_BLOCK_SIZE);


   glUseProgram(asteroid_sp);
   glUniformMatrix4fv(asteroid_view_mat_loc, 1, GL_FALSE, value_ptr(view_mat));
   glUniformMatrix4fv(asteroid_proj_mat_loc, 1, GL_FALSE, value_ptr(proj_mat));

   glUniformBlockBinding(asteroid_sp, asteroid_sp_models_ub_index, ub_binding_point);
   glBindBufferRange(GL_UNIFORM_BUFFER, ub_binding_point, ubo, 0, GL_MAX_UNIFORM_BLOCK_SIZE);


   glUseProgram(texture_sp);
   glUniformMatrix4fv(view_mat_loc, 1, GL_FALSE, value_ptr(view_mat));
   glUniformMatrix4fv(proj_mat_loc, 1, GL_FALSE, value_ptr(proj_mat));

   glUniformBlockBinding(texture_sp, texture_sp_models_ub_index, ub_binding_point);
   glBindBufferRange(GL_UNIFORM_BUFFER, ub_binding_point, ubo, 0, GL_MAX_UNIFORM_BLOCK_SIZE);


   glUseProgram(laser_sp);
   glUniformMatrix4fv(laser_view_mat_loc, 1, GL_FALSE, value_ptr(view_mat));
   glUniformMatrix4fv(laser_proj_mat_loc, 1, GL_FALSE, value_ptr(proj_mat));
   glUniform3f(laser_color_loc, 0.2f, 1.0f, 0.2f);

   glUniformBlockBinding(laser_sp, laser_sp_models_ub_index, ub_binding_point);
   glBindBufferRange(GL_UNIFORM_BUFFER, ub_binding_point, ubo, 0, GL_MAX_UNIFORM_BLOCK_SIZE);


   glUseProgram(explosion_sp);
   glUniformBlockBinding(explosion_sp, explosion_sp_models_ub_index, ub_binding_point);
   glBindBufferRange(GL_UNIFORM_BUFFER, ub_binding_point, ubo, 0, GL_MAX_UNIFORM_BLOCK_SIZE);


   bool cam_moved = false;

   int frame_count = 0;
   double elapsed_seconds_fps = 0.0f;
   double elapsed_seconds_spawn = 0.0f;
   double previous_seconds = glfwGetTime();

   // This draws wireframes. Useful for seeing separate faces and occluded objects.
   //glPolygonMode(GL_FRONT, GL_LINE);

   // disable vsync to see real framerate
   //glfwSwapInterval(0);

   State curState = STATE_MAIN_MENU;

   while (!glfwWindowShouldClose(window) && isRunning) {
      double current_seconds = glfwGetTime();
      double elapsed_seconds = current_seconds - previous_seconds;

      // temporary code to get around vsync issue in OSX Sierra
      if (elapsed_seconds < (1.0f / TARGET_FPS)) {
        continue;
      }

      previous_seconds = current_seconds;

      elapsed_seconds_fps += elapsed_seconds;
      if (elapsed_seconds_fps > 0.25f) {
         fps = (double)frame_count / elapsed_seconds_fps;

         frame_count = 0;
         elapsed_seconds_fps = 0.0f;
      }

      frame_count++;

      // Handle events

      clickedObject = NULL;

      // reset the all key states to KEY_STATE_UNCHANGED (something the GLFW key callback can never return)
      // so that GLFW_PRESS and GLFW_RELEASE are only detected once
      // TODO: Change this if we ever need to act on GLFW_REPEAT (which is when a key is held down
      //  continuously for a period of time)
      fill(key_state, key_state + NUM_KEYS, KEY_STATE_UNCHANGED);

      glfwPollEvents();

      while (!events.empty()) {
         switch (events.front()) {
            case EVENT_GO_TO_MAIN_MENU:
               curState = STATE_MAIN_MENU;
               break;
            case EVENT_GO_TO_GAME:
               curState = STATE_GAME;
               break;
            case EVENT_QUIT:
               isRunning = false;
               break;
         }
         events.pop();
      }

      if (curState == STATE_GAME) {

         elapsed_seconds_spawn += elapsed_seconds;
         if (elapsed_seconds_spawn > 0.5f) {
            SceneObject* obj = createAsteroid(vec3(getRandomNum(-1.3f, 1.3f), -1.2f, getRandomNum(-5.5f, -4.5f)), asteroid_sp);
            addObjectToScene(obj, shaderBufferInfo,
               points_vbo,
               colors_vbo,
               selected_colors_vbo,
               texcoords_vbo,
               normals_vbo,
               ubo,
               model_mat_idx_vbo,
               asteroid_sp);

            elapsed_seconds_spawn -= 0.5f;
         }

         /*
         if (clickedObject == &objects[0]) {
            selectedObject = &objects[0];
         }
         if (clickedObject == &objects[1]) {
            selectedObject = &objects[1];
         }
         */

         /*
         if (key_state[GLFW_KEY_SPACE] == GLFW_PRESS) {
            transformObject(objects[1], translate(mat4(1.0f), vec3(0.3f, 0.0f, 0.0f)), ubo);
         }
         if (key_down[GLFW_KEY_RIGHT]) {
            transformObject(objects[2], translate(mat4(1.0f), vec3(0.01f, 0.0f, 0.0f)), ubo);
         }
         if (key_down[GLFW_KEY_LEFT]) {
            transformObject(objects[2], translate(mat4(1.0f), vec3(-0.01f, 0.0f, 0.0f)), ubo);
         }
         */

         if (key_down[GLFW_KEY_RIGHT]) {
            transformObject(*objects[0], translate(mat4(1.0f), vec3(0.01f, 0.0f, 0.0f)), ubo);

            if (leftLaser != NULL && !leftLaser->deleted) {
               translateLaser(leftLaser, vec3(0.01f, 0.0f, 0.0f), ubo);
            }
            if (rightLaser != NULL && !rightLaser->deleted) {
               translateLaser(rightLaser, vec3(0.01f, 0.0f, 0.0f), ubo);
            }
         }
         if (key_down[GLFW_KEY_LEFT]) {
            transformObject(*objects[0], translate(mat4(1.0f), vec3(-0.01f, 0.0f, 0.0f)), ubo);

            if (leftLaser != NULL && !leftLaser->deleted) {
               translateLaser(leftLaser, vec3(-0.01f, 0.0f, 0.0f), ubo);
            }
            if (rightLaser != NULL && !rightLaser->deleted) {
               translateLaser(rightLaser, vec3(-0.01f, 0.0f, 0.0f), ubo);
            }
         }

         if (key_state[GLFW_KEY_Z] == GLFW_PRESS) {
            vec3 offset(objects[0]->model_transform * vec4(0.0f, 0.0f, 0.0f, 1.0f));

            leftLaser = createLaser(vec3(-0.21f, -1.19f, 1.76f)+offset, vec3(-0.21f, -1.19f, -3.0f)+offset,
               vec3(0.0f, 1.0f, 0.0f), 0.03f, laser_sp);
            addObjectToScene(leftLaser, shaderBufferInfo,
               points_vbo,
               colors_vbo,
               selected_colors_vbo,
               texcoords_vbo,
               normals_vbo,
               ubo,
               model_mat_idx_vbo,
               asteroid_sp);
         } else if (key_state[GLFW_KEY_Z] == GLFW_RELEASE) {
            removeObjectFromScene(*leftLaser, ubo);
         }

         if (key_state[GLFW_KEY_X] == GLFW_PRESS) {
            vec3 offset(objects[0]->model_transform * vec4(0.0f, 0.0f, 0.0f, 1.0f));

            rightLaser = createLaser(vec3(0.21f, -1.19f, 1.76f) + offset, vec3(0.21f, -1.19f, -3.0f) + offset,
               vec3(0.0f, 1.0f, 0.0f), 0.03f, laser_sp);
            addObjectToScene(rightLaser, shaderBufferInfo,
               points_vbo,
               colors_vbo,
               selected_colors_vbo,
               texcoords_vbo,
               normals_vbo,
               ubo,
               model_mat_idx_vbo,
               asteroid_sp);
         } else if (key_state[GLFW_KEY_X] == GLFW_RELEASE) {
            removeObjectFromScene(*rightLaser, ubo);
         }

         // this code moves the asteroids
         for (unsigned int i = 0; i < objects.size(); i++) {
            if (objects[i]->type == TYPE_ASTEROID && !objects[i]->deleted) {
               transformObject(*objects[i], translate(mat4(1.0f), vec3(0.0f, 0.0f, 0.04f)), ubo);

               vec3 obj_center = vec3(view_mat * vec4(objects[i]->bounding_center, 1.0f));

               if ((obj_center.z - objects[i]->bounding_radius) > -NEAR_CLIP) {
                  removeObjectFromScene(*objects[i], ubo);
               }
               // MARKER: Continue code review from here
               if (((Asteroid*)objects[i])->hp <= 0) {
                  // TODO: Optimize this so I don't recalculate the camera rotation every time
                  float cam_pitch = -50.0f * 2.0f * 3.14159f / 360.0f;
                  mat4 pitch_mat = rotate(mat4(1.0f), cam_pitch, vec3(1.0f, 0.0f, 0.0f));
                  mat4 model_mat = translate(mat4(1.0f), objects[i]->bounding_center + vec3(0.0f, 0.0f, 0.0f)) * pitch_mat;

                  removeObjectFromScene(*objects[i], ubo);
                  score++;

                  objExplosion->model_mat = model_mat;

                  // initiate an explosion
                  glUseProgram(explosion_sp);

                  GLuint model_mat_loc = glGetUniformLocation(explosion_sp, "model_mat");
                  glUniformMatrix4fv(model_mat_loc, 1, GL_FALSE, value_ptr(objExplosion->model_mat));

                  glUniform1f(explosion_start_time_loc, (GLfloat)glfwGetTime());
               }
            }
         }

         if (leftLaser != NULL && !leftLaser->deleted) {
            updateLaserTarget(leftLaser, objects, points_vbo, asteroid_sp);
         }
         if (rightLaser != NULL && !rightLaser->deleted) {
            updateLaserTarget(rightLaser, objects, points_vbo, asteroid_sp);
         }
      }

      for (vector<EffectOverTime*>::iterator it = effects.begin(); it != effects.end(); ) {
         if ((*it)->deleted || (*it)->effectedObject->deleted) {
            delete *it;
            it = effects.erase(it);
         } else {
            EffectOverTime* eot = *it;
            eot->effectedValue = eot->startValue + (current_seconds - eot->startTime) * eot->changePerSecond;

            it++;
         }
      }

      if (key_state[GLFW_KEY_ESCAPE] == GLFW_PRESS) {
         glfwSetWindowShouldClose(window, 1);
      }

      float dist = cam_speed * elapsed_seconds;
      if (key_down[GLFW_KEY_A]) {
         vec3 dir = vec3(inverse(R) * vec4(-1.0f, 0.0f, 0.0f, 1.0f));
         cam_pos += dir * dist;

         cam_moved = true;
      }
      if (key_down[GLFW_KEY_D]) {
         vec3 dir = vec3(inverse(R) * vec4(1.0f, 0.0f, 0.0f, 1.0f));
         cam_pos += dir * dist;

         cam_moved = true;
      }
      if (key_down[GLFW_KEY_W]) {
         vec3 dir = vec3(inverse(R) * vec4(0.0f, 0.0f, -1.0f, 1.0f));
         cam_pos += dir * dist;

         cam_moved = true;
      }
      if (key_down[GLFW_KEY_S]) {
         vec3 dir = vec3(inverse(R) * vec4(0.0f, 0.0f, 1.0f, 1.0f));
         cam_pos += dir * dist;

         cam_moved = true;
      }
      /*
      if (key_down[GLFW_KEY_LEFT]) {
      cam_yaw += cam_yaw_speed * elapsed_seconds;
      cam_moved = true;
      }
      if (key_down[GLFW_KEY_RIGHT]) {
      cam_yaw -= cam_yaw_speed * elapsed_seconds;
      cam_moved = true;
      }
      if (key_down[GLFW_KEY_UP]) {
      cam_pitch += cam_pitch_speed * elapsed_seconds;
      cam_moved = true;
      }
      if (key_down[GLFW_KEY_DOWN]) {
      cam_pitch -= cam_pitch_speed * elapsed_seconds;
      cam_moved = true;
      }
      */
      if (cam_moved && false) { // disable camera movement
         T = translate(mat4(1.0f), vec3(-cam_pos.x, -cam_pos.y, -cam_pos.z));

         mat4 yaw_mat = rotate(mat4(1.0f), -cam_yaw, vec3(0.0f, 1.0f, 0.0f));
         mat4 pitch_mat = rotate(mat4(1.0f), -cam_pitch, vec3(1.0f, 0.0f, 0.0f));
         R = pitch_mat * yaw_mat;

         view_mat = R * T;

         //printVector("cam pos", cam_pos);

         glUseProgram(color_sp);
         glUniformMatrix4fv(view_test_loc, 1, GL_FALSE, value_ptr(view_mat));

         glUseProgram(texture_sp);
         glUniformMatrix4fv(view_mat_loc, 1, GL_FALSE, value_ptr(view_mat));

         glUseProgram(laser_sp);
         glUniformMatrix4fv(laser_view_mat_loc, 1, GL_FALSE, value_ptr(view_mat));

         cam_moved = false;
      }

      glUseProgram(explosion_sp);
      glUniform1f(cur_time_loc, (GLfloat)current_seconds);

      // Render scene

      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

      switch (curState) {
         case STATE_MAIN_MENU:
            renderMainMenu();
            renderMainMenuGui();
            break;
         case STATE_GAME:
            renderScene(shaderBufferInfo,
               color_sp, asteroid_sp, texture_sp, laser_sp, explosion_sp,
               color_vao, asteroid_vao, texture_vao, laser_vao, explosion_vao,
               colors_vbo, selected_colors_vbo, ubo,
               selectedObject);
            renderSceneGui();
            break;
      }

      glfwSwapBuffers(window);
   }

   ImGui_ImplGlfwGL3_Shutdown();
   ImGui::DestroyContext();

   glfwDestroyWindow(window);
   glfwTerminate();

   // free memory

   for (vector<SceneObject*>::iterator it = objects.begin(); it != objects.end(); it++) {
      delete *it;
   }

   return 0;
}

void glfw_error_callback(int error, const char* description) {
   gl_log_err("GLFW ERROR: code %i msg: %s\n", error, description);
}

void mouse_button_callback(GLFWwindow* window, int button, int action, int mods) {
   double mouse_x, mouse_y;
   glfwGetCursorPos(window, &mouse_x, &mouse_y);

   if (button == GLFW_MOUSE_BUTTON_LEFT && action == GLFW_PRESS) {
      cout << "Mouse clicked (" << mouse_x << "," << mouse_y << ")" << endl;
      selectedObject = NULL;

      float x = (2.0f*mouse_x) / width - 1.0f;
      float y = 1.0f - (2.0f*mouse_y) / height;

      cout << "x: " << x << ", y: " << y << endl;

      vec4 ray_clip = vec4(x, y, -1.0f, 1.0f);
      vec4 ray_eye = inverse(proj_mat) * ray_clip;
      ray_eye = vec4(vec2(ray_eye), -1.0f, 1.0f);
      vec4 ray_world = inverse(view_mat) * ray_eye;

      vec4 click_point;
      vec3 closest_point = vec3(0.0f, 0.0f, -FAR_CLIP); // Any valid point will be closer than the far clipping plane, so initial value to that
      SceneObject* closest_object = NULL;

      for (vector<SceneObject*>::iterator it = objects.begin(); it != objects.end(); it++) {
         if ((*it)->type == TYPE_LASER) continue;
         for (unsigned int p_idx = 0; p_idx < (*it)->points.size(); p_idx += 9) {
            if (faceClicked(
               {
                  vec3((*it)->points[p_idx], (*it)->points[p_idx + 1], (*it)->points[p_idx + 2]),
                  vec3((*it)->points[p_idx + 3], (*it)->points[p_idx + 4], (*it)->points[p_idx + 5]),
                  vec3((*it)->points[p_idx + 6], (*it)->points[p_idx + 7], (*it)->points[p_idx + 8]),
               },
               *it, ray_world, vec4(cam_pos, 1.0f), click_point
            )) {
               click_point = view_mat * click_point;

               if (-NEAR_CLIP >= click_point.z && click_point.z > -FAR_CLIP && click_point.z > closest_point.z) {
                  closest_point = vec3(click_point);
                  closest_object = *it;
               }
            }
         }
      }

      if (closest_object == NULL) {
         cout << "No object was clicked" << endl;
      } else {
         clickedObject = closest_object;
         cout << "Clicked object: " << clickedObject->id << endl;
      }
   }
}

void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods) {
   key_state[key] = action;

   // should be true for GLFW_PRESS and GLFW_REPEAT
   key_down[key] = (action != GLFW_RELEASE);
}

void APIENTRY debugGlCallback(
   GLenum source,
   GLenum type,
   GLuint id,
   GLenum severity,
   GLsizei length,
   const GLchar* message,
   const void* userParam
) {
   string strMessage(message);

   // TODO: Use C++ strings directly
   char source_str[2048];
   char type_str[2048];
   char severity_str[2048];

   switch (source) {
   case 0x8246:
      strcpy(source_str, "API");
      break;
   case 0x8247:
      strcpy(source_str, "WINDOW_SYSTEM");
      break;
   case 0x8248:
      strcpy(source_str, "SHADER_COMPILER");
      break;
   case 0x8249:
      strcpy(source_str, "THIRD_PARTY");
      break;
   case 0x824A:
      strcpy(source_str, "APPLICATION");
      break;
   case 0x824B:
      strcpy(source_str, "OTHER");
      break;
   default:
      strcpy(source_str, "undefined");
      break;
   }

   switch (type) {
   case 0x824C:
      strcpy(type_str, "ERROR");
      break;
   case 0x824D:
      strcpy(type_str, "DEPRECATED_BEHAVIOR");
      break;
   case 0x824E:
      strcpy(type_str, "UNDEFINED_BEHAVIOR");
      break;
   case 0x824F:
      strcpy(type_str, "PORTABILITY");
      break;
   case 0x8250:
      strcpy(type_str, "PERFORMANCE");
      break;
   case 0x8251:
      strcpy(type_str, "OTHER");
      break;
   case 0x8268:
      strcpy(type_str, "MARKER");
      break;
   case 0x8269:
      strcpy(type_str, "PUSH_GROUP");
      break;
   case 0x826A:
      strcpy(type_str, "POP_GROUP");
      break;
   default:
      strcpy(type_str, "undefined");
      break;
   }
   switch (severity) {
   case 0x9146:
      strcpy(severity_str, "HIGH");
      break;
   case 0x9147:
      strcpy(severity_str, "MEDIUM");
      break;
   case 0x9148:
      strcpy(severity_str, "LOW");
      break;
   case 0x826B:
      strcpy(severity_str, "NOTIFICATION");
      break;
   default:
      strcpy(severity_str, "undefined");
      break;
   }

   if (string(severity_str) != "NOTIFICATION") {
      cout << "OpenGL Error!!!" << endl;
      cout << "Source: " << string(source_str) << endl;
      cout << "Type: " << string(type_str) << endl;
      cout << "Severity: " << string(severity_str) << endl;
      cout << strMessage << endl;
   }
}


GLuint loadShader(GLenum type, string file) {
  cout << "Loading shader from file " << file << endl;

  ifstream shaderFile(file);
  GLuint shaderId = 0;

  if (shaderFile.is_open()) {
    string line, shaderString;

    while(getline(shaderFile, line)) {
      shaderString += line + "\n";
    }
    shaderFile.close();
    const char* shaderCString = shaderString.c_str();

    shaderId = glCreateShader(type);
    glShaderSource(shaderId, 1, &shaderCString, NULL);
    glCompileShader(shaderId);

    cout << "Loaded successfully" << endl;
  } else {
    cout << "Failed to load the file" << endl;
  }

  return shaderId;
}

GLuint loadShaderProgram(string vertexShaderPath, string fragmentShaderPath) {
   GLuint vs = loadShader(GL_VERTEX_SHADER, vertexShaderPath);
   GLuint fs = loadShader(GL_FRAGMENT_SHADER, fragmentShaderPath);

   GLuint shader_program = glCreateProgram();
   glAttachShader(shader_program, vs);
   glAttachShader(shader_program, fs);

   glLinkProgram(shader_program);

   return shader_program;
}

unsigned char* loadImage(string file_name, int* x, int* y) {
  int n;
  int force_channels = 4; // This forces RGBA (4 bytes per pixel)
  unsigned char* image_data = stbi_load(file_name.c_str(), x, y, &n, force_channels);

  int width_in_bytes = *x * 4;
  unsigned char *top = NULL;
  unsigned char *bottom = NULL;
  unsigned char temp = 0;
  int half_height = *y / 2;

  // flip image upside-down to account for OpenGL treating lower-left as (0, 0)
  for (int row = 0; row < half_height; row++) {
     top = image_data + row * width_in_bytes;
     bottom = image_data + (*y - row - 1) * width_in_bytes;
     for (int col = 0; col < width_in_bytes; col++) {
        temp = *top;
        *top = *bottom;
        *bottom = temp;
        top++;
        bottom++;
     }
  }

  if (!image_data) {
    fprintf(stderr, "ERROR: could not load %s\n", file_name.c_str());
  }

  // Not Power-of-2 check
  if ((*x & (*x - 1)) != 0 || (*y & (*y - 1)) != 0) {
     fprintf(stderr, "WARNING: texture %s is not power-of-2 dimensions\n", file_name.c_str());
  }

  return image_data;
}

bool faceClicked(array<vec3, 3> points, SceneObject* obj, vec4 world_ray, vec4 cam, vec4& click_point) {
   // LINE EQUATION:            P = O + Dt
   // O = cam
   // D = ray_world

   // PLANE EQUATION:   P dot n + d = 0
   // n is the normal vector
   // d is the offset from the origin

   // Take the cross-product of two vectors on the plane to get the normal
   vec3 v1 = points[1] - points[0];
   vec3 v2 = points[2] - points[0];

   vec3 normal = vec3(v1.y*v2.z - v1.z*v2.y, v1.z*v2.x - v1.x*v2.z, v1.x*v2.y - v1.y*v2.x);

   vec3 local_ray = vec3(inverse(obj->model_mat) * world_ray);
   vec3 local_cam = vec3(inverse(obj->model_mat) * cam);

   local_ray = local_ray - local_cam;

   float d = -glm::dot(points[0], normal);
   float t = -(glm::dot(local_cam, normal) + d) / glm::dot(local_ray, normal);

   vec3 intersection = local_cam + t*local_ray;

   if (insideTriangle(intersection, points)) {
      click_point = obj->model_mat * vec4(intersection, 1.0f);
      return true;
   } else {
      return false;
   }
}

bool insideTriangle(vec3 p, array<vec3, 3> triangle_points) {
   vec3 v21 = triangle_points[1] - triangle_points[0];
   vec3 v31 = triangle_points[2] - triangle_points[0];
   vec3 pv1 = p - triangle_points[0];

   float y = (pv1.y*v21.x - pv1.x*v21.y) / (v31.y*v21.x - v31.x*v21.y);
   float x = (pv1.x-y*v31.x) / v21.x;

   return x > 0.0f && y > 0.0f && x+y < 1.0f;
}

void printVector(string label, vec3& v) {
   cout << label << " -> (" << v.x << "," << v.y << "," << v.z << ")" << endl;
}

void print4DVector(string label, vec4& v) {
   cout << label << " -> (" << v.x << "," << v.y << "," << v.z << "," << v.w << ")" << endl;
}

void initObject(SceneObject* obj) {
   // Each objects must have at least 3 points, so the size of
   // the points array must be a positive multiple of 9
   if (obj->points.size() == 0 || (obj->points.size() % 9) != 0) {
      // TODO: Maybe throw some kind of error here instead
      return;
   }

   obj->id = objects.size(); // currently unused
   obj->num_points = obj->points.size() / 3;
   obj->model_transform = mat4(1.0f);
   obj->deleted = false;

   obj->normals.reserve(obj->points.size());
   for (unsigned int i = 0; i < obj->points.size(); i += 9) {
      vec3 point1 = vec3(obj->points[i], obj->points[i + 1], obj->points[i + 2]);
      vec3 point2 = vec3(obj->points[i + 3], obj->points[i + 4], obj->points[i + 5]);
      vec3 point3 = vec3(obj->points[i + 6], obj->points[i + 7], obj->points[i + 8]);

      vec3 normal = normalize(cross(point2 - point1, point3 - point1));

      // Add the same normal for all 3 points
      for (int j = 0; j < 3; j++) {
         obj->normals.push_back(normal.x);
         obj->normals.push_back(normal.y);
         obj->normals.push_back(normal.z);
      }
   }

   if (obj->type == TYPE_SHIP || obj->type == TYPE_ASTEROID) {
      calculateObjectBoundingBox(obj);

      obj->bounding_center = vec3(obj->translate_mat * vec4(obj->bounding_center, 1.0f));
   }
}

void addObjectToScene(SceneObject* obj,
   map<GLuint, BufferInfo>& shaderBufferInfo,
   GLuint points_vbo,
   GLuint colors_vbo,
   GLuint selected_colors_vbo,
   GLuint texcoords_vbo,
   GLuint normals_vbo,
   GLuint ubo,
   GLuint model_mat_idx_vbo,
   GLuint asteroid_sp) {
   objects.push_back(obj);

   BufferInfo* bufferInfo = &shaderBufferInfo[obj->shader_program];

   // Check if the buffers aren't large enough to fit the new object and, if so, call
   // populateBuffers() to resize and repopupulate them
   if (bufferInfo->vbo_capacity < (bufferInfo->vbo_offset + obj->num_points) ||
      bufferInfo->ubo_capacity < (bufferInfo->ubo_offset + 1)) {

      if (leftLaser != NULL && leftLaser->deleted) {
         leftLaser = NULL;
      }
      if (rightLaser != NULL && rightLaser->deleted) {
         rightLaser = NULL;
      }

      populateBuffers(objects, shaderBufferInfo,
         points_vbo,
         colors_vbo,
         selected_colors_vbo,
         texcoords_vbo,
         normals_vbo,
         ubo,
         model_mat_idx_vbo,
         asteroid_sp);
   } else {
      copyObjectDataToBuffers(*objects.back(), shaderBufferInfo,
         points_vbo,
         colors_vbo,
         selected_colors_vbo,
         texcoords_vbo,
         normals_vbo,
         ubo,
         model_mat_idx_vbo,
         asteroid_sp);
   }
}

void removeObjectFromScene(SceneObject& obj, GLuint ubo) {
   if (!obj.deleted) {
      // Move the object outside the render bounds of the scene so it doesn't get rendered
      // TODO: Find a better way of hiding the object until the next time buffers are repopulated
      transformObject(obj, translate(mat4(1.0f), vec3(0.0f, 0.0f, FAR_CLIP * 1000.0f)), ubo);
      obj.deleted = true;
   }
}

void calculateObjectBoundingBox(SceneObject* obj) {
   GLfloat min_x = obj->points[0];
   GLfloat max_x = obj->points[0];
   GLfloat min_y = obj->points[1];
   GLfloat max_y = obj->points[1];
   GLfloat min_z = obj->points[2];
   GLfloat max_z = obj->points[2];

   // start from the second point
   for (unsigned int i = 3; i < obj->points.size(); i += 3) {
      if (min_x > obj->points[i]) {
         min_x = obj->points[i];
      }
      else if (max_x < obj->points[i]) {
         max_x = obj->points[i];
      }

      if (min_y > obj->points[i + 1]) {
         min_y = obj->points[i + 1];
      }
      else if (max_y < obj->points[i + 1]) {
         max_y = obj->points[i + 1];
      }

      if (min_z > obj->points[i + 2]) {
         min_z = obj->points[i + 2];
      }
      else if (max_z < obj->points[i + 2]) {
         max_z = obj->points[i + 2];
      }
   }

   obj->bounding_center = vec3((min_x + max_x) / 2.0f, (min_y + max_y) / 2.0f, (min_z + max_z) / 2.0f);

   GLfloat radius_x = max_x - obj->bounding_center.x;
   GLfloat radius_y = max_y - obj->bounding_center.y;
   GLfloat radius_z = max_z - obj->bounding_center.z;

   // TODO: This actually underestimates the radius. Might need to be fixed at some point.
   // TODO: Does not take into account any scaling in the model matrix
   obj->bounding_radius = radius_x;
   if (obj->bounding_radius < radius_y)
      obj->bounding_radius = radius_y;
   if (obj->bounding_radius < radius_z)
      obj->bounding_radius = radius_z;

   for (unsigned int i = 0; i < obj->points.size(); i += 3) {
      obj->points[i] -= obj->bounding_center.x;
      obj->points[i + 1] -= obj->bounding_center.y;
      obj->points[i + 2] -= obj->bounding_center.z;
   }

   obj->bounding_center = vec3(0.0f, 0.0f, 0.0f);
}

SceneObject* createShip(GLuint shader) {
   SceneObject* ship = new SceneObject();

   ship->type = TYPE_SHIP;
   ship->shader_program = shader;

   ship->points = {
      //back
      -0.5f,    0.3f,    0.0f,
      -0.5f,    0.0f,    0.0f,
      0.5f,    0.0f,    0.0f,
      -0.5f,    0.3f,    0.0f,
      0.5f,    0.0f,    0.0f,
      0.5f,    0.3f,    0.0f,

      // left back
      -0.5f,    0.3f,   -2.0f,
      -0.5f,    0.0f,   -2.0f,
      -0.5f,    0.0f,    0.0f,
      -0.5f,    0.3f,   -2.0f,
      -0.5f,    0.0f,    0.0f,
      -0.5f,    0.3f,    0.0f,

      // right back
      0.5f,    0.3f,    0.0f,
      0.5f,    0.0f,    0.0f,
      0.5f,    0.0f,   -2.0f,
      0.5f,    0.3f,    0.0f,
      0.5f,    0.0f,   -2.0f,
      0.5f,    0.3f,   -2.0f,

      // left mid
      -0.25f,   0.3f,   -3.0f,
      -0.25f,   0.0f,   -3.0f,
      -0.5f,    0.0f,   -2.0f,
      -0.25f,   0.3f,   -3.0f,
      -0.5f,    0.0f,   -2.0f,
      -0.5f,    0.3f,   -2.0f,

      // right mid
      0.5f,    0.3f,   -2.0f,
      0.5f,    0.0f,   -2.0f,
      0.25f,   0.0f,   -3.0f,
      0.5f,    0.3f,   -2.0f,
      0.25f,   0.0f,   -3.0f,
      0.25f,   0.3f,   -3.0f,

      // left front
      0.0f,    0.0f,   -3.5f,
      -0.25f,   0.0f,   -3.0f,
      -0.25f,   0.3f,   -3.0f,

      // right front
      0.25f,   0.3f,   -3.0f,
      0.25f,   0.0f,   -3.0f,
      0.0f,    0.0f,   -3.5f,

      // top back
      -0.5f,    0.3f,   -2.0f,
      -0.5f,    0.3f,    0.0f,
      0.5f,    0.3f,    0.0f,
      -0.5f,    0.3f,   -2.0f,
      0.5f,    0.3f,    0.0f,
      0.5f,    0.3f,   -2.0f,

      // bottom back
      -0.5f,    0.0f,    0.0f,
      -0.5f,    0.0f,   -2.0f,
      0.5f,    0.0f,    0.0f,
      0.5f,    0.0f,    0.0f,
      -0.5f,    0.0f,   -2.0f,
      0.5f,    0.0f,   -2.0f,

      // top mid
      -0.25f,   0.3f,   -3.0f,
      -0.5f,    0.3f,   -2.0f,
      0.5f,    0.3f,   -2.0f,
      -0.25f,   0.3f,   -3.0f,
      0.5f,    0.3f,   -2.0f,
      0.25f,   0.3f,   -3.0f,

      // bottom mid
      -0.5f,    0.0f,   -2.0f,
      -0.25f,   0.0f,   -3.0f,
      0.5f,    0.0f,   -2.0f,
      0.5f,    0.0f,   -2.0f,
      -0.25f,   0.0f,   -3.0f,
      0.25f,   0.0f,   -3.0f,

      // top front
      -0.25f,   0.3f,   -3.0f,
      0.25f,   0.3f,   -3.0f,
      0.0f,    0.0f,   -3.5f,

      // bottom front
      0.25f,   0.0f,   -3.0f,
      -0.25f,   0.0f,   -3.0f,
      0.0f,    0.0f,   -3.5f,

      // left wing start back
      -1.5f,    0.3f,    0.0f,
      -1.5f,    0.0f,    0.0f,
      -0.5f,    0.0f,    0.0f,
      -1.5f,    0.3f,    0.0f,
      -0.5f,    0.0f,    0.0f,
      -0.5f,    0.3f,    0.0f,

      // left wing start top
      -0.5f,    0.3f,   -0.3f,
      -1.3f,    0.3f,   -0.3f,
      -1.5f,    0.3f,    0.0f,
      -0.5f,    0.3f,   -0.3f,
      -1.5f,    0.3f,    0.0f,
      -0.5f,    0.3f,    0.0f,

      // left wing start front
      -0.5f,    0.3f,   -0.3f,
      -0.5f,    0.0f,   -0.3f,
      -1.3f,    0.0f,   -0.3f,
      -0.5f,    0.3f,   -0.3f,
      -1.3f,    0.0f,   -0.3f,
      -1.3f,    0.3f,   -0.3f,

      // left wing start bottom
      -0.5f,    0.0f,    0.0f,
      -1.5f,    0.0f,    0.0f,
      -1.3f,    0.0f,   -0.3f,
      -0.5f,    0.0f,    0.0f,
      -1.3f,    0.0f,   -0.3f,
      -0.5f,    0.0f,   -0.3f,

      // left wing end outside
      -1.5f,    0.3f,    0.0f,
      -2.2f,    0.15f,  -0.8f,
      -1.5f,    0.0f,    0.0f,

      // left wing end top
      -1.3f,    0.3f,   -0.3f,
      -2.2f,    0.15f,  -0.8f,
      -1.5f,    0.3f,    0.0f,

      // left wing end front
      -1.3f,    0.0f,   -0.3f,
      -2.2f,    0.15f,  -0.8f,
      -1.3f,    0.3f,   -0.3f,

      // left wing end bottom
      -1.5f,    0.0f,    0.0f,
      -2.2f,    0.15f,  -0.8f,
      -1.3f,    0.0f,   -0.3f,

      // right wing start back
      1.5f,    0.0f,    0.0f,
      1.5f,    0.3f,    0.0f,
      0.5f,    0.0f,    0.0f,
      0.5f,    0.0f,    0.0f,
      1.5f,    0.3f,    0.0f,
      0.5f,    0.3f,    0.0f,

      // right wing start top
      1.3f,    0.3f,   -0.3f,
      0.5f,    0.3f,   -0.3f,
      1.5f,    0.3f,    0.0f,
      1.5f,    0.3f,    0.0f,
      0.5f,    0.3f,   -0.3f,
      0.5f,    0.3f,    0.0f,

      // right wing start front
      0.5f,    0.0f,   -0.3f,
      0.5f,    0.3f,   -0.3f,
      1.3f,    0.0f,   -0.3f,
      1.3f,    0.0f,   -0.3f,
      0.5f,    0.3f,   -0.3f,
      1.3f,    0.3f,   -0.3f,

      // right wing start bottom
      1.5f,    0.0f,    0.0f,
      0.5f,    0.0f,    0.0f,
      1.3f,    0.0f,   -0.3f,
      1.3f,    0.0f,   -0.3f,
      0.5f,    0.0f,    0.0f,
      0.5f,    0.0f,   -0.3f,

      // right wing end outside
      2.2f,    0.15f,  -0.8f,
      1.5f,    0.3f,    0.0f,
      1.5f,    0.0f,    0.0f,

      // right wing end top
      2.2f,    0.15f,  -0.8f,
      1.3f,    0.3f,   -0.3f,
      1.5f,    0.3f,    0.0f,

      // right wing end front
      2.2f,    0.15f,  -0.8f,
      1.3f,    0.0f,   -0.3f,
      1.3f,    0.3f,   -0.3f,

      // right wing end bottom
      2.2f,    0.15f,  -0.8f,
      1.5f,    0.0f,    0.0f,
      1.3f,    0.0f,   -0.3f,
   };
   ship->colors = {
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,

      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,

      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,

      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,

      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,

      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,
      0.0f, 0.0f, 1.0f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,

      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
      0.0f, 0.0f, 0.3f,
   };
   ship->texcoords = { 0.0f };
   ship->selected_colors = { 0.0f };

   mat4 T_model = translate(mat4(1.0f), vec3(0.0f, -1.2f, 1.65f));
   mat4 R_model(1.0f);
   ship->model_base = T_model * R_model * scale(mat4(1.0f), vec3(0.1f, 0.1f, 0.1f));

   ship->translate_mat = T_model;

   initObject(ship);

   return ship;
}

/* LASER RENDERING/POSITIONING ALGORITHM
 * -Draw a thin rectangle for the laser beam, using the specified width and endpoints
 * -Texture the beam with a grayscale partially transparent image
 * -In the shader, blend the image with a color to support lasers of different colors
 *
 * The flat part of the textured rectangle needs to always face the camera, so the laser's width is constant
 * This is done as follows:
* -Determine the length of the laser based on the start and end points
* -Draw a rectangle along the z-axis and rotated upwards along the y-axis, with the correct final length and width
* -Rotate the beam around the z-axis by the correct angle, sot that in its final position, the flat part faces the camera
* -Rotate the beam along the x-axis and then along the y-axis and then translate it to put it into its final position
*/
// TODO: Make the color parameter have an effect
Laser* createLaser(vec3 start, vec3 end, vec3 color, GLfloat width, GLuint laser_sp) {
   Laser* obj = new Laser();
   obj->type = TYPE_LASER;
   obj->targetAsteroid = NULL;
   obj->shader_program = laser_sp;

   vec3 ray = end - start;
   float length = glm::length(ray);

   obj->points = {
       width / 2, 0.0f, -width / 2,
      -width / 2, 0.0f, -width / 2,
      -width / 2, 0.0f, 0.0f,
       width / 2, 0.0f, -width / 2,
      -width / 2, 0.0f, 0.0f,
       width / 2, 0.0f, 0.0f,
       width / 2, 0.0f, -length + width / 2,
      -width / 2, 0.0f, -length + width / 2,
      -width / 2, 0.0f, -width / 2,
       width / 2, 0.0f, -length + width / 2,
      -width / 2, 0.0f, -width / 2,
       width / 2, 0.0f, -width / 2,
       width / 2, 0.0f, -length,
      -width / 2, 0.0f, -length,
      -width / 2, 0.0f, -length + width / 2,
       width / 2, 0.0f, -length,
      -width / 2, 0.0f, -length + width / 2,
       width / 2, 0.0f, -length + width / 2,
   };

   obj->texcoords = {
      1.0f, 0.5f,
      0.0f, 0.5f,
      0.0f, 0.0f,
      1.0f, 0.5f,
      0.0f, 0.0f,
      1.0f, 0.0f,
      1.0f, 0.51f,
      0.0f, 0.51f,
      0.0f, 0.49f,
      1.0f, 0.51f,
      0.0f, 0.49f,
      1.0f, 0.49f,
      1.0f, 1.0f,
      0.0f, 1.0f,
      0.0f, 0.5f,
      1.0f, 1.0f,
      0.0f, 0.5f,
      1.0f, 0.5f,
   };

   float xAxisRotation = asin(ray.y / length);
   float yAxisRotation = atan2(-ray.x, -ray.z);

   vec3 normal(rotate(mat4(1.0f), yAxisRotation, vec3(0.0f, 1.0f, 0.0f)) *
               rotate(mat4(1.0f), xAxisRotation, vec3(1.0f, 0.0f, 0.0f)) *
               vec4(0.0f, 1.0f, 0.0f, 1.0f));

   // To project point P onto line AB:
   // projection = A + dot(AP,AB) / dot(AB,AB) * AB
   vec3 projOnLaser = start + glm::dot(cam_pos-start, ray) / (length*length) * ray;
   vec3 laserToCam = cam_pos - projOnLaser;

   float zAxisRotation = -atan2(glm::dot(glm::cross(normal, laserToCam), glm::normalize(ray)), glm::dot(normal, laserToCam));

   obj->model_base = rotate(mat4(1.0f), zAxisRotation, vec3(0.0f, 0.0f, 1.0f));

   initObject(obj);

   obj->model_transform = rotate(mat4(1.0f), xAxisRotation, vec3(1.0f, 0.0f, 0.0f)) * obj->model_transform;
   obj->model_transform = rotate(mat4(1.0f), yAxisRotation, vec3(0.0f, 1.0f, 0.0f)) * obj->model_transform;
   obj->model_transform = translate(mat4(1.0f), start) * obj->model_transform;

   return obj;
}

void initializeBuffers(
                  GLuint* points_vbo,
                  GLuint* colors_vbo,
                  GLuint* selected_colors_vbo,
                  GLuint* texcoords_vbo,
                  GLuint* normals_vbo,
                  GLuint* ubo,
                  GLuint* model_mat_idx_vbo) {
   *points_vbo = 0;
   glGenBuffers(1, points_vbo);

   *colors_vbo = 0;
   glGenBuffers(1, colors_vbo);

   *selected_colors_vbo = 0;
   glGenBuffers(1, selected_colors_vbo);

   *texcoords_vbo = 0;
   glGenBuffers(1, texcoords_vbo);

   *normals_vbo = 0;
   glGenBuffers(1, normals_vbo);

   *ubo = 0;
   glGenBuffers(1, ubo);

   *model_mat_idx_vbo = 0;
   glGenBuffers(1, model_mat_idx_vbo);
}

GLuint initializeParticleEffectBuffers(vec3 origin, mat4 proj, mat4 view, GLuint explosion_sp,
                  map<GLuint, BufferInfo>& shaderBufferInfo,
                  GLuint points_vbo,
                  GLuint colors_vbo,
                  GLuint selected_colors_vbo,
                  GLuint texcoords_vbo,
                  GLuint normals_vbo,
                  GLuint ubo,
                  GLuint model_mat_idx_vbo) {
   float vv[EXPLOSION_PARTICLE_COUNT * 3]; // initial velocities vec3
   float vt[EXPLOSION_PARTICLE_COUNT]; // initial times
   float t_accum = 0.0f; // start time

   for (int i = 0; i < EXPLOSION_PARTICLE_COUNT; i++) {
      vt[i] = t_accum;
      t_accum += 0.01f;

      float randx = ((float)rand() / (float)RAND_MAX) - 0.5f;
      float randy = ((float)rand() / (float)RAND_MAX) - 0.5f;
      vv[i*3] = randx;
      vv[i*3 + 1] = randy;
      vv[i*3 + 2] = 0.0f;
   }

   mat4 model_mat = translate(mat4(1.0f), origin);

   glUseProgram(explosion_sp);

   GLuint proj_mat_loc = glGetUniformLocation(explosion_sp, "proj");
   GLuint view_mat_loc = glGetUniformLocation(explosion_sp, "view");

   glUniformMatrix4fv(proj_mat_loc, 1, GL_FALSE, value_ptr(proj));
   glUniformMatrix4fv(view_mat_loc, 1, GL_FALSE, value_ptr(view));

   GLuint model_mat_loc = glGetUniformLocation(explosion_sp, "model_mat");

   glUniformMatrix4fv(model_mat_loc, 1, GL_FALSE, value_ptr(model_mat));

   GLuint velocity_vbo;
   glGenBuffers(1, &velocity_vbo);
   glBindBuffer(GL_ARRAY_BUFFER, velocity_vbo);
   glBufferData(GL_ARRAY_BUFFER, sizeof(vv), vv, GL_STATIC_DRAW);

   GLuint time_vbo;
   glGenBuffers(1, &time_vbo);
   glBindBuffer(GL_ARRAY_BUFFER, time_vbo);
   glBufferData(GL_ARRAY_BUFFER, sizeof(vt), vt, GL_STATIC_DRAW);

   GLuint vao;
   glGenVertexArrays(1, &vao);
   glBindVertexArray(vao);

   glEnableVertexAttribArray(0);
   glEnableVertexAttribArray(1);

   glBindBuffer(GL_ARRAY_BUFFER, velocity_vbo);
   glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   glBindBuffer(GL_ARRAY_BUFFER, time_vbo);
   glVertexAttribPointer(1, 1, GL_FLOAT, GL_FALSE, 0, NULL);

   objExplosion = createExplosion(explosion_sp);
   addObjectToScene(objExplosion, shaderBufferInfo,
      points_vbo,
      colors_vbo,
      selected_colors_vbo,
      texcoords_vbo,
      normals_vbo,
      ubo,
      model_mat_idx_vbo,
      0);

   return vao;
}

void populateBuffers(vector<SceneObject*>& objects,
                  map<GLuint, BufferInfo>& shaderBufferInfo,
                  GLuint points_vbo,
                  GLuint colors_vbo,
                  GLuint selected_colors_vbo,
                  GLuint texcoords_vbo,
                  GLuint normals_vbo,
                  GLuint ubo,
                  GLuint ubo_idx_vbo,
                  GLuint asteroid_sp) {
   GLsizeiptr num_points = 0;
   GLsizeiptr num_objects = 0;

   map<GLuint, unsigned int> shaderCounts;
   map<GLuint, unsigned int> shaderUboCounts;

   map<GLuint, BufferInfo>::iterator shaderIt;

   for (shaderIt = shaderBufferInfo.begin(); shaderIt != shaderBufferInfo.end(); shaderIt++) {
      shaderCounts[shaderIt->first] = 0;
      shaderUboCounts[shaderIt->first] = 0;
   }

   vector<SceneObject*>::iterator it;

   /* Find all shaders that need to be used and the number of objects and
   * number of points for each shader. Construct a map from shader id to count
   * of points being drawn using that shader (for thw model matrix ubo, we
   * need object counts instead). These will be used to get offsets into the
   * vertex buffer for each shader.
   */
   for (it = objects.begin(); it != objects.end(); ) {
      if ((*it)->deleted) {
         delete *it;
         it = objects.erase(it);
      } else {
         num_points += (*it)->num_points;
         num_objects++;

         shaderCounts[(*it)->shader_program] += (*it)->num_points;
         shaderUboCounts[(*it)->shader_program]++;

         it++;
      }
   }

   // double the buffer sizes to leave room for new objects
   num_points *= 2;
   num_objects *= 2;

   map<GLuint, unsigned int>::iterator shaderCountIt;
   unsigned int lastShaderCount = 0;
   unsigned int lastShaderUboCount = 0;

   /*
   * The counts calculated above can be used to get the starting offset of
   * each shader in the vertex buffer. Create a map of base offsets to mark
   * where the data for the first object using a given shader begins. Also,
   * create a map of current offsets to mark where to copy data for the next
   * object being added.
   */
   for (shaderCountIt = shaderCounts.begin(); shaderCountIt != shaderCounts.end(); shaderCountIt++) {
      // When populating the buffers, leave as much empty space as space taken up by existing objects
      // to allow new objects to be added without immediately having to resize the buffers
      shaderBufferInfo[shaderCountIt->first].vbo_base = lastShaderCount * 2;
      shaderBufferInfo[shaderCountIt->first].ubo_base = lastShaderUboCount * 2;

      shaderBufferInfo[shaderCountIt->first].vbo_offset = 0;
      shaderBufferInfo[shaderCountIt->first].ubo_offset = 0;

      shaderBufferInfo[shaderCountIt->first].vbo_capacity = shaderCounts[shaderCountIt->first] * 2;
      shaderBufferInfo[shaderCountIt->first].ubo_capacity = shaderUboCounts[shaderCountIt->first] * 2;

      lastShaderCount += shaderCounts[shaderCountIt->first];
      lastShaderUboCount += shaderUboCounts[shaderCountIt->first];
   }

   // Allocate all the buffers using the counts calculated above

   glBindBuffer(GL_ARRAY_BUFFER, points_vbo);
   glBufferData(GL_ARRAY_BUFFER, num_points * sizeof(GLfloat) * 3, NULL, GL_DYNAMIC_DRAW);

   glBindBuffer(GL_ARRAY_BUFFER, colors_vbo);
   glBufferData(GL_ARRAY_BUFFER, num_points * sizeof(GLfloat) * 3, NULL, GL_DYNAMIC_DRAW);

   glBindBuffer(GL_ARRAY_BUFFER, selected_colors_vbo);
   glBufferData(GL_ARRAY_BUFFER, num_points * sizeof(GLfloat) * 3, NULL, GL_DYNAMIC_DRAW);

   glBindBuffer(GL_ARRAY_BUFFER, texcoords_vbo);
   glBufferData(GL_ARRAY_BUFFER, num_points * sizeof(GLfloat) * 2, NULL, GL_DYNAMIC_DRAW);

   glBindBuffer(GL_ARRAY_BUFFER, normals_vbo);
   glBufferData(GL_ARRAY_BUFFER, num_points * sizeof(GLfloat) * 3, NULL, GL_DYNAMIC_DRAW);

   glBindBuffer(GL_UNIFORM_BUFFER, ubo);
   glBufferData(GL_UNIFORM_BUFFER, num_objects * sizeof(mat4), NULL, GL_DYNAMIC_DRAW);

   glBindBuffer(GL_ARRAY_BUFFER, ubo_idx_vbo);
   glBufferData(GL_ARRAY_BUFFER, num_points * sizeof(GLuint), NULL, GL_DYNAMIC_DRAW);

   for (it = objects.begin(); it != objects.end(); it++) {
      copyObjectDataToBuffers(**it, shaderBufferInfo,
         points_vbo,
         colors_vbo,
         selected_colors_vbo,
         texcoords_vbo,
         normals_vbo,
         ubo,
         ubo_idx_vbo,
         asteroid_sp);
   }
}

void copyObjectDataToBuffers(SceneObject& obj,
                  map<GLuint, BufferInfo>& shaderBufferInfo,
                  GLuint points_vbo,
                  GLuint colors_vbo,
                  GLuint selected_colors_vbo,
                  GLuint texcoords_vbo,
                  GLuint normals_vbo,
                  GLuint ubo,
                  GLuint model_mat_idx_vbo,
                  GLuint asteroid_sp) {
   BufferInfo* bufferInfo = &shaderBufferInfo[obj.shader_program];

   obj.vertex_vbo_offset = bufferInfo->vbo_base + bufferInfo->vbo_offset;
   obj.ubo_offset = bufferInfo->ubo_base + bufferInfo->ubo_offset;

   if (obj.ubo_offset == 0) {
      objFirst = &obj;
   }

   if (obj.type != TYPE_EXPLOSION) {
      glBindBuffer(GL_ARRAY_BUFFER, model_mat_idx_vbo);
      for (unsigned int i = 0; i < obj.num_points; i++) {
         glBufferSubData(GL_ARRAY_BUFFER, (obj.vertex_vbo_offset + i) * sizeof(GLuint), sizeof(GLuint), &obj.ubo_offset);
      }

      glBindBuffer(GL_ARRAY_BUFFER, points_vbo);
      glBufferSubData(GL_ARRAY_BUFFER, obj.vertex_vbo_offset * sizeof(GLfloat) * 3, obj.points.size() * sizeof(GLfloat), &obj.points[0]);

      glBindBuffer(GL_ARRAY_BUFFER, texcoords_vbo);
      glBufferSubData(GL_ARRAY_BUFFER, obj.vertex_vbo_offset * sizeof(GLfloat) * 2, obj.texcoords.size() * sizeof(GLfloat), &obj.texcoords[0]);

      if (obj.type != TYPE_LASER) {
         glBindBuffer(GL_ARRAY_BUFFER, colors_vbo);
         glBufferSubData(GL_ARRAY_BUFFER, obj.vertex_vbo_offset * sizeof(GLfloat) * 3, obj.colors.size() * sizeof(GLfloat), &obj.colors[0]);

         glBindBuffer(GL_ARRAY_BUFFER, selected_colors_vbo);
         glBufferSubData(GL_ARRAY_BUFFER, obj.vertex_vbo_offset * sizeof(GLfloat) * 3, obj.selected_colors.size() * sizeof(GLfloat), &obj.selected_colors[0]);

         glBindBuffer(GL_ARRAY_BUFFER, normals_vbo);
         glBufferSubData(GL_ARRAY_BUFFER, obj.vertex_vbo_offset * sizeof(GLfloat) * 3, obj.normals.size() * sizeof(GLfloat), &obj.normals[0]);
      }

      obj.model_mat = obj.model_transform * obj.model_base;
      glBindBuffer(GL_UNIFORM_BUFFER, ubo);
      glBufferSubData(GL_UNIFORM_BUFFER, obj.ubo_offset * sizeof(mat4), sizeof(mat4), value_ptr(obj.model_mat));

      if (obj.type == TYPE_ASTEROID) {
         glUseProgram(asteroid_sp);

         ostringstream oss;
         oss << "hp[" << obj.ubo_offset << "]";
         glUniform1f(glGetUniformLocation(asteroid_sp, oss.str().c_str()), ((Asteroid*)&obj)->hp);
      }
   }

   bufferInfo->vbo_offset += obj.num_points;
   bufferInfo->ubo_offset++;
}

void transformObject(SceneObject& obj, const mat4& transform, GLuint ubo) {
   if (obj.deleted) return;

   obj.model_transform = transform * obj.model_transform;
   obj.model_mat = obj.model_transform * obj.model_base;

   obj.bounding_center = vec3(transform * vec4(obj.bounding_center, 1.0f));

   glBindBuffer(GL_UNIFORM_BUFFER, ubo);
   glBufferSubData(GL_UNIFORM_BUFFER, obj.ubo_offset * sizeof(mat4), sizeof(mat4), value_ptr(obj.model_mat));
}

void translateLaser(Laser* laser, const vec3& translation, GLuint ubo) {
   // TODO: A lot of the values calculated here can be calculated once and saved when the laser is created,
   // and then re-used here

   vec3 start = vec3(laser->model_transform * vec4(0.0f, 0.0f, 0.0f, 1.0f));
   vec3 end = vec3(laser->model_transform * vec4(0.0f, 0.0f, laser->points[38], 1.0f));

   vec3 ray = end - start;
   float length = glm::length(ray);

   float xAxisRotation = asin(ray.y / length);
   float yAxisRotation = atan2(-ray.x, -ray.z);

   vec3 normal(rotate(mat4(1.0f), yAxisRotation, vec3(0.0f, 1.0f, 0.0f)) *
      rotate(mat4(1.0f), xAxisRotation, vec3(1.0f, 0.0f, 0.0f)) *
      vec4(0.0f, 1.0f, 0.0f, 1.0f));

   // To project point P onto line AB:
   // projection = A + dot(AP,AB) / dot(AB,AB) * AB
   vec3 projOnLaser = start + glm::dot(cam_pos - start, ray) / (length*length) * ray;
   vec3 laserToCam = cam_pos - projOnLaser;

   float zAxisRotation = -atan2(glm::dot(glm::cross(normal, laserToCam), glm::normalize(ray)), glm::dot(normal, laserToCam));

   laser->model_base = rotate(mat4(1.0f), zAxisRotation, vec3(0.0f, 0.0f, 1.0f));

   transformObject(*laser, translate(mat4(1.0f), translation), ubo);
}

void updateLaserTarget(Laser* laser, vector<SceneObject*>& objects, GLuint points_vbo, GLuint asteroid_sp) {
   // TODO: A lot of the values calculated here can be calculated once and saved when the laser is created,
   // and then re-used here

   vec3 start = vec3(laser->model_transform * vec4(0.0f, 0.0f, 0.0f, 1.0f));
   vec3 end = vec3(laser->model_transform * vec4(0.0f, 0.0f, laser->points[2] + laser->points[20], 1.0f));

   vec3 intersection(0.0f), closestIntersection(0.0f);
   Asteroid* closestAsteroid = NULL;

   for (vector<SceneObject*>::iterator it = objects.begin(); it != objects.end(); it++) {
      if ((*it)->type == TYPE_ASTEROID && !(*it)->deleted && getLaserAndAsteroidIntersection(start, end, **it, intersection)) {
         // TODO: Implement a more generic algorithm for testing the closest object by getting the distance between the points
         if (closestAsteroid == NULL || intersection.z > closestIntersection.z) {
            // TODO: At this point, find the real intersection of the laser with one of the asteroid's sides
            closestAsteroid = (Asteroid*)*it;
            closestIntersection = intersection;
         }
      }
   }

   float width = laser->points[0] - laser->points[2];

   if (laser->targetAsteroid != closestAsteroid) {
      if (laser->targetAsteroid != NULL) {
         if (laser == leftLaser) {
            leftLaserEffect->deleted = true;
         } else if (laser == rightLaser) {
            rightLaserEffect->deleted = true;
         }
      }

      EffectOverTime* eot = NULL;

      if (closestAsteroid != NULL) {
         eot = new EffectOverTime(closestAsteroid->hp, -20.0f, closestAsteroid);
         effects.push_back(eot);
      }

      if (laser == leftLaser) {
         leftLaserEffect = eot;
      } else if (laser == rightLaser) {
         rightLaserEffect = eot;
      }
   }
   laser->targetAsteroid = closestAsteroid;

   float length = 5.24f; // I think this was to make sure the laser went past the end of the screen
   if (closestAsteroid != NULL) {
      length = glm::length(closestIntersection - start);

      // TODO: Find a more generic way of updating the laser hp than in updateLaserTarget

      glUseProgram(asteroid_sp);

      ostringstream oss;
      oss << "hp[" << closestAsteroid->ubo_offset << "]";
      glUniform1f(glGetUniformLocation(asteroid_sp, oss.str().c_str()), closestAsteroid->hp);
   }

   laser->points[20] = -length + width / 2;
   laser->points[23] = -length + width / 2;
   laser->points[29] = -length + width / 2;
   laser->points[38] = -length;
   laser->points[41] = -length;
   laser->points[44] = -length + width / 2;
   laser->points[47] = -length;
   laser->points[50] = -length + width / 2;
   laser->points[53] = -length + width / 2;

   glBindBuffer(GL_ARRAY_BUFFER, points_vbo);
   glBufferSubData(GL_ARRAY_BUFFER, laser->vertex_vbo_offset * sizeof(GLfloat) * 3, laser->points.size() * sizeof(GLfloat), &laser->points[0]);
}

bool getLaserAndAsteroidIntersection(vec3& start, vec3& end, SceneObject& asteroid, vec3& intersection) {
   /*
   ### LINE EQUATIONS ###
   x = x1 + u * (x2 - x1)
   y = y1 + u * (y2 - y1)
   z = z1 + u * (z2 - z1)

   ### SPHERE EQUATION ###
   (x - x3)^2 + (y - y3)^2 + (z - z3)^2 = r^2

   ### QUADRATIC EQUATION TO SOLVE ###
   a*u^2 + b*u + c = 0
   WHERE THE CONSTANTS ARE
   a = (x2 - x1)^2 + (y2 - y1)^2 + (z2 - z1)^2
   b = 2*( (x2 - x1)*(x1 - x3) + (y2 - y1)*(y1 - y3) + (z2 - z1)*(z1 - z3) )
   c = x3^2 + y3^2 + z3^2 + x1^2 + y1^2 + z1^2 - 2(x3*x1 + y3*y1 + z3*z1) - r^2

   u = (-b +- sqrt(b^2 - 4*a*c)) / 2a

   If the value under the root is >= 0, we got an intersection
   If the value > 0, there are two solutions. Take the one closer to 0, since that's the
   one closer to the laser start point
   */

   vec3& center = asteroid.bounding_center;

   float a = pow(end.x-start.x, 2) + pow(end.y-start.y, 2) + pow(end.z-start.z, 2);
   float b = 2*((start.x-end.x)*(start.x-center.x) + (end.y-start.y)*(start.y-center.y) + (end.z-start.z)*(start.z-center.z));
   float c = pow(center.x, 2) + pow(center.y, 2) + pow(center.z, 2) + pow(start.x, 2) + pow(start.y, 2) + pow(start.z, 2) - 2*(center.x*start.x + center.y*start.y + center.z*start.z) - pow(asteroid.bounding_radius, 2);
   float discriminant = pow(b, 2) - 4*a*c;

   if (discriminant >= 0.0f) {
      // In this case, the negative root will always give the point closer to the laser start point
      float u = (-b - sqrt(discriminant)) / (2 * a);

      // Check that the intersection is within the line segment corresponding to the laser
      if (0.0f <= u && u <= 1.0f) {
         intersection = start + u * (end - start);
         return true;
      }
   }

   return false;
}

void renderScene(map<GLuint, BufferInfo>& shaderBufferInfo,
                  GLuint color_sp, GLuint asteroid_sp, GLuint texture_sp, GLuint laser_sp, GLuint explosion_sp,
                  GLuint color_vao, GLuint asteroid_vao, GLuint texture_vao, GLuint laser_vao, GLuint explosion_vao,
                  GLuint colors_vbo, GLuint selected_colors_vbo, GLuint ubo,
                  SceneObject* selectedObject) {

   glUseProgram(color_sp);
   glBindVertexArray(color_vao);

   /*
   if (selectedObject != NULL) {
      glBindBuffer(GL_ARRAY_BUFFER, selected_colors_vbo);
      glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, NULL);

      glDrawArrays(GL_TRIANGLES, selectedObject->vertex_vbo_offset, selectedObject->num_points);
   }
   */

   // Uncomment this code when I want to use selected colors again
   // glBindBuffer(GL_ARRAY_BUFFER, colors_vbo);
   // glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, NULL);

   glDrawArrays(GL_TRIANGLES, shaderBufferInfo[color_sp].vbo_base, shaderBufferInfo[color_sp].vbo_offset);

   glUseProgram(asteroid_sp);
   glBindVertexArray(asteroid_vao);

   glDrawArrays(GL_TRIANGLES, shaderBufferInfo[asteroid_sp].vbo_base, shaderBufferInfo[asteroid_sp].vbo_offset);

   glUseProgram(texture_sp);
   glBindVertexArray(texture_vao);

   glDrawArrays(GL_TRIANGLES, shaderBufferInfo[texture_sp].vbo_base, shaderBufferInfo[texture_sp].vbo_offset);

   glEnable(GL_BLEND);

   glUseProgram(laser_sp);
   glBindVertexArray(laser_vao);

   glDrawArrays(GL_TRIANGLES, shaderBufferInfo[laser_sp].vbo_base, shaderBufferInfo[laser_sp].vbo_offset);

   glUseProgram(explosion_sp);

   glEnable(GL_PROGRAM_POINT_SIZE);
   glBindVertexArray(explosion_vao);

   glBindBuffer(GL_UNIFORM_BUFFER, ubo);
   glBufferSubData(GL_UNIFORM_BUFFER, 0, sizeof(mat4), value_ptr(objExplosion->model_mat));

   glDrawArrays(GL_POINTS, 0, shaderBufferInfo[explosion_sp].vbo_offset);

   glBindBuffer(GL_UNIFORM_BUFFER, ubo);
   glBufferSubData(GL_UNIFORM_BUFFER, 0, sizeof(mat4), value_ptr(objFirst->model_mat));

   glDisable(GL_PROGRAM_POINT_SIZE);
   glDisable(GL_BLEND);
}

void renderSceneGui() {
   ImGui_ImplGlfwGL3_NewFrame();

   // 1. Show a simple window.
   // Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets automatically appears in a window called "Debug".
   /*
   {
      static float f = 0.0f;
      static int counter = 0;
      ImGui::Text("Hello, world!");                           // Display some text (you can use a format string too)
      ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f    
      ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color

      ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our windows open/close state
      ImGui::Checkbox("Another Window", &show_another_window);

      if (ImGui::Button("Button"))                            // Buttons return true when clicked (NB: most widgets return true when edited/activated)
         counter++;
      ImGui::SameLine();
      ImGui::Text("counter = %d", counter);

      ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
   }
   */

   stringstream ssScore, ssFps;
   ssScore << "Score: " << score;
   ssFps << "FPS:   " << fps;

   {
      ImGui::SetNextWindowSize(ImVec2(95, 46), ImGuiCond_Once);
      ImGui::SetNextWindowPos(ImVec2(10, 50), ImGuiCond_Once);
      ImGui::Begin("WndStats", NULL,
         ImGuiWindowFlags_NoTitleBar |
         ImGuiWindowFlags_NoResize |
         ImGuiWindowFlags_NoMove);
      ImGui::Text(ssScore.str().c_str());
      ImGui::Text(ssFps.str().c_str());
      ImGui::End();
   }

   {
      ImGui::SetNextWindowPos(ImVec2(380, 10), ImGuiCond_Once);
      ImGui::SetNextWindowSize(ImVec2(250, 35), ImGuiCond_Once);
      ImGui::Begin("WndMenubar", NULL,
         ImGuiWindowFlags_NoTitleBar |
         ImGuiWindowFlags_NoResize |
         ImGuiWindowFlags_NoMove);
      ImGui::InvisibleButton("", ImVec2(155, 18));
      ImGui::SameLine();
      if (ImGui::Button("Main Menu")) {
         events.push(EVENT_GO_TO_MAIN_MENU);
      }
      ImGui::End();
   }

   ImGui::Render();
   ImGui_ImplGlfwGL3_RenderDrawData(ImGui::GetDrawData());
}

void renderMainMenu() {
}

void renderMainMenuGui() {
   ImGui_ImplGlfwGL3_NewFrame();

   {
      int padding = 4;
      ImGui::SetNextWindowPos(ImVec2(-padding, -padding), ImGuiCond_Once);
      ImGui::SetNextWindowSize(ImVec2(width + 2 * padding, height + 2 * padding), ImGuiCond_Once);
      ImGui::Begin("WndMain", NULL,
         ImGuiWindowFlags_NoTitleBar |
         ImGuiWindowFlags_NoResize |
         ImGuiWindowFlags_NoMove);

      ImGui::InvisibleButton("", ImVec2(10, 80));
      ImGui::InvisibleButton("", ImVec2(285, 18));
      ImGui::SameLine();
      if (ImGui::Button("New Game")) {
         events.push(EVENT_GO_TO_GAME);
      }

      ImGui::InvisibleButton("", ImVec2(10, 15));
      ImGui::InvisibleButton("", ImVec2(300, 18));
      ImGui::SameLine();
      if (ImGui::Button("Quit")) {
         events.push(EVENT_QUIT);
      }

      ImGui::End();
   }

   ImGui::Render();
   ImGui_ImplGlfwGL3_RenderDrawData(ImGui::GetDrawData());
}

Asteroid* createAsteroid(vec3 pos, GLuint shader) {
   Asteroid* obj = new Asteroid();
   obj->type = TYPE_ASTEROID;
   obj->shader_program = shader;
   obj->hp = 10.0f;

   obj->points = {
      // front
      1.0f,  1.0f,  1.0f,
      -1.0f,  1.0f,  1.0f,
      -1.0f, -1.0f,  1.0f,
      1.0f,  1.0f,  1.0f,
      -1.0f, -1.0f,  1.0f,
      1.0f, -1.0f,  1.0f,

      // top
      1.0f,  1.0f, -1.0f,
      -1.0f,  1.0f, -1.0f,
      -1.0f,  1.0f,  1.0f,
      1.0f,  1.0f, -1.0f,
      -1.0f,  1.0f,  1.0f,
      1.0f,  1.0f,  1.0f,

      // bottom
      1.0f, -1.0f,  1.0f,
      -1.0f, -1.0f,  1.0f,
      -1.0f, -1.0f, -1.0f,
      1.0f, -1.0f,  1.0f,
      -1.0f, -1.0f, -1.0f,
      1.0f, -1.0f, -1.0f,

      // back
      1.0f,  1.0f, -1.0f,
      -1.0f, -1.0f, -1.0f,
      -1.0f,  1.0f, -1.0f,
      1.0f,  1.0f, -1.0f,
      1.0f, -1.0f, -1.0f,
      -1.0f, -1.0f, -1.0f,

      // right
      1.0f,  1.0f, -1.0f,
      1.0f,  1.0f,  1.0f,
      1.0f, -1.0f,  1.0f,
      1.0f,  1.0f, -1.0f,
      1.0f, -1.0f,  1.0f,
      1.0f, -1.0f, -1.0f,

      // left
      -1.0f,  1.0f,  1.0f,
      -1.0f,  1.0f, -1.0f,
      -1.0f, -1.0f, -1.0f,
      -1.0f,  1.0f,  1.0f,
      -1.0f, -1.0f, -1.0f,
      -1.0f, -1.0f,  1.0f,
   };
   obj->colors = {
      // front
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,

      // top
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,

      // bottom
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,

      // back
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,

      // right
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,

      // left
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
      0.4f, 0.4f, 0.4f,
   };
   obj->texcoords = { 0.0f };
   obj->selected_colors = { 0.0f };

   mat4 T = translate(mat4(1.0f), pos);
   mat4 R = rotate(mat4(1.0f), 60.0f * (float)ONE_DEG_IN_RAD, vec3(1.0f, 1.0f, -1.0f));
   obj->model_base = T * R * scale(mat4(1.0f), vec3(0.1f, 0.1f, 0.1f));

   obj->translate_mat = T;

   initObject(obj);
   // This accounts for the scaling in model_base.
   // Dividing by 8 instead of 10 since the bounding radius algorithm
   // under-calculates the true value.
   // TODO: Once the intersection check with the sides of the asteroid is done,
   // this can be removed.
   obj->bounding_radius /= 8.0f;

   return obj;
}

SceneObject* createExplosion(GLuint shader) {
   SceneObject* obj = new SceneObject();
   obj->type = TYPE_EXPLOSION;
   obj->shader_program = shader;

   obj->points = {};
   obj->colors = {};

   initObject(obj);
   obj->num_points = EXPLOSION_PARTICLE_COUNT;

   return obj;
}

float getRandomNum(float low, float high) {
   return low + ((float)rand()/RAND_MAX) * (high-low);
}