Changeset fe70cd3 in opengl-game for game.cpp

Timestamp:

Jun 28, 2017, 3:12:16 AM (8 years ago)

Author:

Dmitry Portnoy <dmp1488@…>

Branches:

feature/imgui-sdl, master, points-test

Children:

4813066, 669c4e6

Parents:

92bc4fe

Message:

Update the build instructions for Linux

File:

• game.cpp (modified) (4 diffs)

game.cpp

@@ -22 +22 @@
 void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
 
+GLint compileVertexShader(const GLchar**);
+GLint compileFragmentShader(const GLchar**);
+
+GLint linkShaderProgram(initializer_list<GLint>);
+
 const GLuint WIDTH = 800, HEIGHT = 600;
+
+// Shaders
+const GLchar* vertexShaderSource = "#version 330 core\n"
+   "layout (location = 0) in vec3 position;\n"
+   "void main()\n"
+   "{\n"
+   "gl_Position = vec4(position.x, position.y, position.z, 1.0);\n"
+   "}\0";
+const GLchar* fragmentShaderSource = "#version 330 core\n"
+   "out vec4 color;\n"
+   "void main()\n"
+   "{\n"
+   "color = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
+   "}\n\0";
 
 int main(int argc, char* argv[]) {
@@ -68 +87 @@
    glViewport(0, 0, width, height);
 
+   GLint vertexShader = compileVertexShader(&vertexShaderSource);
+   GLint fragmentShader = compileFragmentShader(&fragmentShaderSource);
+
+   GLint shaderProgram = linkShaderProgram({vertexShader, fragmentShader});
+
+   glDeleteShader(vertexShader);
+   glDeleteShader(fragmentShader);
+
+   // Set up vertex data (and buffer(s)) and attribute pointers
+   //GLfloat vertices[] = {
+   //  // First triangle
+   //   0.5f,  0.5f,  // Top Right
+   //   0.5f, -0.5f,  // Bottom Right
+   //  -0.5f,  0.5f,  // Top Left 
+   //  // Second triangle
+   //   0.5f, -0.5f,  // Bottom Right
+   //  -0.5f, -0.5f,  // Bottom Left
+   //  -0.5f,  0.5f   // Top Left
+   //};
+   GLfloat vertices[] = {
+       0.5f,  0.5f, 0.0f,  // Top Right
+       0.5f, -0.5f, 0.0f,  // Bottom Right
+      -0.5f,  0.5f, 0.0f,  // Top Left 
+       0.5f, -0.5f, 0.0f,  // Bottom Right
+      -0.5f, -0.5f, 0.0f,  // Bottom Left
+      -0.5f,  0.5f, 0.0f   // Top Left 
+   };
+   GLuint indices[] = {  // Note that we start from 0!
+      0, 1, 3,  // First Triangle
+      1, 2, 3   // Second Triangle
+   };
+   GLuint VBO, VAO, EBO;
+   glGenVertexArrays(1, &VAO);
+   glGenBuffers(1, &VBO);
+   //glGenBuffers(1, &EBO);
+   // Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointer(s).
+   glBindVertexArray(VAO);
+
+   glBindBuffer(GL_ARRAY_BUFFER, VBO);
+   glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+   //glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+   //glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
+
+   glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3*sizeof(GLfloat), (GLvoid*)0);
+   glEnableVertexAttribArray(0);
+
+   glBindBuffer(GL_ARRAY_BUFFER, 0); // Note that this is allowed, the call to glVertexAttribPointer registered VBO as the currently bound vertex buffer object so afterwards we can safely unbind
+
+   glBindVertexArray(0); // Unbind VAO (it's always a good thing to unbind any buffer/array to prevent strange bugs), remember: do NOT unbind the EBO, keep it bound to this VAO
+
+   // Uncommenting this call will result in wireframe polygons.
+   //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+
    // Game loop
    while (!glfwWindowShouldClose(window)) {
@@ -78 +151 @@
       glClear(GL_COLOR_BUFFER_BIT);
 
+      // Draw our first triangle
+      glUseProgram(shaderProgram);
+      glBindVertexArray(VAO);
+      glDrawArrays(GL_TRIANGLES, 0, 6);
+      //glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+      glBindVertexArray(0);
+
       // Swap the screen buffers
       glfwSwapBuffers(window);
    }
+
+   // Properly de-allocate all resources once they've outlived their purpose
+   glDeleteVertexArrays(1, &VAO);
+   glDeleteBuffers(1, &VBO);
+   //glDeleteBuffers(1, &EBO);
 
    glfwTerminate();
@@ -92 +177 @@
       glfwSetWindowShouldClose(window, GL_TRUE);
 }
+
+GLint compileVertexShader(const GLchar** shaderSource) {
+   GLint vertexShader = glCreateShader(GL_VERTEX_SHADER);
+   glShaderSource(vertexShader, 1, shaderSource, NULL);
+   glCompileShader(vertexShader);
+
+   // Check for compile time errors
+   GLint success;
+   GLchar infoLog[512];
+   glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
+   if (!success) {
+      glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
+      cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED" << endl << infoLog << endl;
+   }
+
+   return vertexShader;
+}
+
+GLint compileFragmentShader(const GLchar** shaderSource) {
+   GLint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+   glShaderSource(fragmentShader, 1, shaderSource, NULL);
+   glCompileShader(fragmentShader);
+
+   // Check for compile time errors
+   GLint success;
+   GLchar infoLog[512];
+   glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
+   if (!success) {
+      glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
+      cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << endl;
+   }
+
+   return fragmentShader;
+}
+
+GLint linkShaderProgram(initializer_list<GLint> shaders) {
+   GLint shaderProgram = glCreateProgram();
+
+   for (auto shader : shaders) {
+      glAttachShader(shaderProgram, shader);
+   }
+
+   glLinkProgram(shaderProgram);
+
+   // Check for linking errors
+   GLint success;
+   GLchar infoLog[512];
+   glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
+   if (!success) {
+      glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
+      cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << endl;
+   }
+
+   return shaderProgram;
+}