OpenGL学习—04--彩色立方体
1.tutorial04.cpp
// Include standard headers #include <stdio.h> #include <stdlib.h> // Include GLEW #include <GL/glew.h> // Include GLFW #include <glfw3.h> GLFWwindow* window; // Include GLM #include <glm/glm.hpp> #include <glm/gtc/matrix_transform.hpp> using namespace glm; #include <common/shader.hpp> int main( void ) { // Initialise GLFW if( !glfwInit() ) { fprintf( stderr, "Failed to initialize GLFW\n" ); getchar(); return -1; } glfwWindowHint(GLFW_SAMPLES, 4); glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // To make MacOS happy; should not be needed glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // Open a window and create its OpenGL context window = glfwCreateWindow( 1024, 768, "Tutorial 04 - Colored Cube", NULL, NULL); if( window == NULL ){ fprintf( stderr, "Failed to open GLFW window. If you have an Intel GPU, they are not 3.3 compatible. Try the 2.1 version of the tutorials.\n" ); getchar(); glfwTerminate(); return -1; } glfwMakeContextCurrent(window); // Initialize GLEW glewExperimental = true; // Needed for core profile if (glewInit() != GLEW_OK) { fprintf(stderr, "Failed to initialize GLEW\n"); getchar(); glfwTerminate(); return -1; } // Ensure we can capture the escape key being pressed below glfwSetInputMode(window, GLFW_STICKY_KEYS, GL_TRUE); // Dark blue background glClearColor(0.0f, 0.0f, 0.4f, 0.0f); // Enable depth test glEnable(GL_DEPTH_TEST); // Accept fragment if it closer to the camera than the former one glDepthFunc(GL_LESS); GLuint VertexArrayID; glGenVertexArrays(1, &VertexArrayID); glBindVertexArray(VertexArrayID); // Create and compile our GLSL program from the shaders GLuint programID = LoadShaders( "TransformVertexShader.vertexshader", "ColorFragmentShader.fragmentshader" ); // Get a handle for our "MVP" uniform GLuint MatrixID = glGetUniformLocation(programID, "MVP"); // 获取渲染器变量 // Projection matrix : 45?Field of View, 4:3 ratio, display range : 0.1 unit <-> 100 units glm::mat4 Projection = glm::perspective(45.0f, 4.0f / 3.0f, 0.1f, 100.0f); // Camera matrix glm::mat4 View = glm::lookAt( glm::vec3(4,3,-3), // Camera is at (4,3,-3), in World Space glm::vec3(0,0,0), // and looks at the origin glm::vec3(0,1,0) // Head is up (set to 0,-1,0 to look upside-down) ); // Model matrix : an identity matrix (model will be at the origin) glm::mat4 Model = glm::mat4(1.0f); // Our ModelViewProjection : multiplication of our 3 matrices glm::mat4 MVP = Projection * View * Model; // Remember, matrix multiplication is the other way around // Our vertices. Tree consecutive floats give a 3D vertex; Three consecutive vertices give a triangle. // A cube has 6 faces with 2 triangles each, so this makes 6*2=12 triangles, and 12*3 vertices static const GLfloat g_vertex_buffer_data[] = { -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, 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, -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, -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, 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, 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 }; // One color for each vertex. They were generated randomly. static const GLfloat g_color_buffer_data[] = { 0.583f, 0.771f, 0.014f, 0.609f, 0.115f, 0.436f, 0.327f, 0.483f, 0.844f, 0.822f, 0.569f, 0.201f, 0.435f, 0.602f, 0.223f, 0.310f, 0.747f, 0.185f, 0.597f, 0.770f, 0.761f, 0.559f, 0.436f, 0.730f, 0.359f, 0.583f, 0.152f, 0.483f, 0.596f, 0.789f, 0.559f, 0.861f, 0.639f, 0.195f, 0.548f, 0.859f, 0.014f, 0.184f, 0.576f, 0.771f, 0.328f, 0.970f, 0.406f, 0.615f, 0.116f, 0.676f, 0.977f, 0.133f, 0.971f, 0.572f, 0.833f, 0.140f, 0.616f, 0.489f, 0.997f, 0.513f, 0.064f, 0.945f, 0.719f, 0.592f, 0.543f, 0.021f, 0.978f, 0.279f, 0.317f, 0.505f, 0.167f, 0.620f, 0.077f, 0.347f, 0.857f, 0.137f, 0.055f, 0.953f, 0.042f, 0.714f, 0.505f, 0.345f, 0.783f, 0.290f, 0.734f, 0.722f, 0.645f, 0.174f, 0.302f, 0.455f, 0.848f, 0.225f, 0.587f, 0.040f, 0.517f, 0.713f, 0.338f, 0.053f, 0.959f, 0.120f, 0.393f, 0.621f, 0.362f, 0.673f, 0.211f, 0.457f, 0.820f, 0.883f, 0.371f, 0.982f, 0.099f, 0.879f }; GLuint vertexbuffer; glGenBuffers(1, &vertexbuffer); // 创建缓冲区 glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); // 绑定缓冲区 glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW); // 填充数据到缓冲区 GLuint colorbuffer; glGenBuffers(1, &colorbuffer); glBindBuffer(GL_ARRAY_BUFFER, colorbuffer); glBufferData(GL_ARRAY_BUFFER, sizeof(g_color_buffer_data), g_color_buffer_data, GL_STATIC_DRAW); do{ // Clear the screen glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Use our shader glUseProgram(programID); // Send our transformation to the currently bound shader, // in the "MVP" uniform glUniformMatrix4fv(MatrixID, 1, GL_FALSE, &MVP[0][0]); // 将变换矩阵放入渲染器中 // 1rst attribute buffer : vertices glEnableVertexAttribArray(0); // 与渲染器变量进行关联 glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); glVertexAttribPointer( 0, // attribute. No particular reason for 0, but must match the layout in the shader. 3, // size GL_FLOAT, // type GL_FALSE, // normalized? 0, // stride (void*)0 // array buffer offset ); // 2nd attribute buffer : colors glEnableVertexAttribArray(1); glBindBuffer(GL_ARRAY_BUFFER, colorbuffer); glVertexAttribPointer( 1, // attribute. No particular reason for 1, but must match the layout in the shader. 3, // size GL_FLOAT, // type GL_FALSE, // normalized? 0, // stride (void*)0 // array buffer offset ); // Draw the triangle ! glDrawArrays(GL_TRIANGLES, 0, 12*3); // 12*3 indices starting at 0 -> 12 triangles glDisableVertexAttribArray(0); glDisableVertexAttribArray(1); // Swap buffers glfwSwapBuffers(window); glfwPollEvents(); } // Check if the ESC key was pressed or the window was closed while( glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS && glfwWindowShouldClose(window) == 0 ); // Cleanup VBO and shader glDeleteBuffers(1, &vertexbuffer); glDeleteBuffers(1, &colorbuffer); glDeleteProgram(programID); glDeleteVertexArrays(1, &VertexArrayID); // Close OpenGL window and terminate GLFW glfwTerminate(); return 0; }
2. common/shader.cpp
#include <stdio.h> #include <string> #include <vector> #include <iostream> #include <fstream> #include <algorithm> using namespace std; #include <stdlib.h> #include <string.h> #include <GL/glew.h> #include "shader.hpp" GLuint LoadShaders(const char * vertex_file_path,const char * fragment_file_path){ // Create the shaders GLuint VertexShaderID = glCreateShader(GL_VERTEX_SHADER); GLuint FragmentShaderID = glCreateShader(GL_FRAGMENT_SHADER); // Read the Vertex Shader code from the file std::string VertexShaderCode; std::ifstream VertexShaderStream(vertex_file_path, std::ios::in); if(VertexShaderStream.is_open()){ std::string Line = ""; while(getline(VertexShaderStream, Line)) VertexShaderCode += "\n" + Line; VertexShaderStream.close(); }else{ printf("Impossible to open %s. Are you in the right directory ? Don't forget to read the FAQ !\n", vertex_file_path); getchar(); return 0; } // Read the Fragment Shader code from the file std::string FragmentShaderCode; std::ifstream FragmentShaderStream(fragment_file_path, std::ios::in); if(FragmentShaderStream.is_open()){ std::string Line = ""; while(getline(FragmentShaderStream, Line)) FragmentShaderCode += "\n" + Line; FragmentShaderStream.close(); } GLint Result = GL_FALSE; int InfoLogLength; // Compile Vertex Shader printf("Compiling shader : %s\n", vertex_file_path); char const * VertexSourcePointer = VertexShaderCode.c_str(); glShaderSource(VertexShaderID, 1, &VertexSourcePointer , NULL); glCompileShader(VertexShaderID); // Check Vertex Shader glGetShaderiv(VertexShaderID, GL_COMPILE_STATUS, &Result); glGetShaderiv(VertexShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength); if ( InfoLogLength > 0 ){ std::vector<char> VertexShaderErrorMessage(InfoLogLength+1); glGetShaderInfoLog(VertexShaderID, InfoLogLength, NULL, &VertexShaderErrorMessage[0]); printf("%s\n", &VertexShaderErrorMessage[0]); } // Compile Fragment Shader printf("Compiling shader : %s\n", fragment_file_path); char const * FragmentSourcePointer = FragmentShaderCode.c_str(); glShaderSource(FragmentShaderID, 1, &FragmentSourcePointer , NULL); glCompileShader(FragmentShaderID); // Check Fragment Shader glGetShaderiv(FragmentShaderID, GL_COMPILE_STATUS, &Result); glGetShaderiv(FragmentShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength); if ( InfoLogLength > 0 ){ std::vector<char> FragmentShaderErrorMessage(InfoLogLength+1); glGetShaderInfoLog(FragmentShaderID, InfoLogLength, NULL, &FragmentShaderErrorMessage[0]); printf("%s\n", &FragmentShaderErrorMessage[0]); } // Link the program printf("Linking program\n"); GLuint ProgramID = glCreateProgram(); glAttachShader(ProgramID, VertexShaderID); glAttachShader(ProgramID, FragmentShaderID); glLinkProgram(ProgramID); // Check the program glGetProgramiv(ProgramID, GL_LINK_STATUS, &Result); glGetProgramiv(ProgramID, GL_INFO_LOG_LENGTH, &InfoLogLength); if ( InfoLogLength > 0 ){ std::vector<char> ProgramErrorMessage(InfoLogLength+1); glGetProgramInfoLog(ProgramID, InfoLogLength, NULL, &ProgramErrorMessage[0]); printf("%s\n", &ProgramErrorMessage[0]); } glDetachShader(ProgramID, VertexShaderID); glDetachShader(ProgramID, FragmentShaderID); glDeleteShader(VertexShaderID); glDeleteShader(FragmentShaderID); return ProgramID; }
3.common/shader.hpp
#ifndef SHADER_HPP #define SHADER_HPP GLuint LoadShaders(const char * vertex_file_path,const char * fragment_file_path); #endif
4.shaders/TransformVertexShader.vertexshader
#version 330 core // Input vertex data, different for all executions of this shader. layout(location = 0) in vec3 vertexPosition_modelspace; layout(location = 1) in vec3 vertexColor; // Output data ; will be interpolated for each fragment. out vec3 fragmentColor; // Values that stay constant for the whole mesh. uniform mat4 MVP; void main(){ // Output position of the vertex, in clip space : MVP * position gl_Position = MVP * vec4(vertexPosition_modelspace,1); // The color of each vertex will be interpolated // to produce the color of each fragment fragmentColor = vertexColor; }
5.shaders/ColorFragmentShader.fragmentshader
#version 330 core // Interpolated values from the vertex shaders in vec3 fragmentColor; // Ouput data out vec3 color; void main(){ // Output color = color specified in the vertex shader, // interpolated between all 3 surrounding vertices color = fragmentColor; }
