OpenGL学习--05--纹理立方体--代码
1.tutorial05.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> #include <common/texture.hpp> int main( void ) { // Initialise GLFW if( !glfwInit() ) { fprintf( stderr, "Failed to initialize GLFW\n" ); 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 05 - Textured 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" ); glfwTerminate(); return -1; } glfwMakeContextCurrent(window); // Initialize GLEW glewExperimental = true; // Needed for core profile if (glewInit() != GLEW_OK) { fprintf(stderr, "Failed to initialize GLEW\n"); 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", "TextureFragmentShader.fragmentshader" ); // Get a handle for our "MVP" uniform GLuint MatrixID = glGetUniformLocation(programID, "MVP"); // 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 // Load the texture using any two methods //GLuint Texture = loadBMP_custom("uvtemplate.bmp"); GLuint Texture = loadDDS("uvtemplate.DDS"); // Get a handle for our "myTextureSampler" uniform GLuint TextureID = glGetUniformLocation(programID, "myTextureSampler"); // 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 }; // Two UV coordinatesfor each vertex. They were created withe Blender. static const GLfloat g_uv_buffer_data[] = { 0.000059f, 1.0f-0.000004f, 0.000103f, 1.0f-0.336048f, 0.335973f, 1.0f-0.335903f, 1.000023f, 1.0f-0.000013f, 0.667979f, 1.0f-0.335851f, 0.999958f, 1.0f-0.336064f, 0.667979f, 1.0f-0.335851f, 0.336024f, 1.0f-0.671877f, 0.667969f, 1.0f-0.671889f, 1.000023f, 1.0f-0.000013f, 0.668104f, 1.0f-0.000013f, 0.667979f, 1.0f-0.335851f, 0.000059f, 1.0f-0.000004f, 0.335973f, 1.0f-0.335903f, 0.336098f, 1.0f-0.000071f, 0.667979f, 1.0f-0.335851f, 0.335973f, 1.0f-0.335903f, 0.336024f, 1.0f-0.671877f, 1.000004f, 1.0f-0.671847f, 0.999958f, 1.0f-0.336064f, 0.667979f, 1.0f-0.335851f, 0.668104f, 1.0f-0.000013f, 0.335973f, 1.0f-0.335903f, 0.667979f, 1.0f-0.335851f, 0.335973f, 1.0f-0.335903f, 0.668104f, 1.0f-0.000013f, 0.336098f, 1.0f-0.000071f, 0.000103f, 1.0f-0.336048f, 0.000004f, 1.0f-0.671870f, 0.336024f, 1.0f-0.671877f, 0.000103f, 1.0f-0.336048f, 0.336024f, 1.0f-0.671877f, 0.335973f, 1.0f-0.335903f, 0.667969f, 1.0f-0.671889f, 1.000004f, 1.0f-0.671847f, 0.667979f, 1.0f-0.335851f }; GLuint vertexbuffer; glGenBuffers(1, &vertexbuffer); glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW); GLuint uvbuffer; glGenBuffers(1, &uvbuffer); glBindBuffer(GL_ARRAY_BUFFER, uvbuffer); glBufferData(GL_ARRAY_BUFFER, sizeof(g_uv_buffer_data), g_uv_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]); // Bind our texture in Texture Unit 0 glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, Texture); // Set our "myTextureSampler" sampler to user Texture Unit 0 glUniform1i(TextureID, 0); // 1rst attribute buffer : vertices glEnableVertexAttribArray(0); 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 : UVs glEnableVertexAttribArray(1); glBindBuffer(GL_ARRAY_BUFFER, uvbuffer); glVertexAttribPointer( 1, // attribute. No particular reason for 1, but must match the layout in the shader. 2, // size : U+V => 2 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, &uvbuffer); glDeleteProgram(programID); glDeleteTextures(1, &TextureID); 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.common/texture.cpp
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <GL/glew.h> #include <glfw3.h> GLuint loadBMP_custom(const char * imagepath){ printf("Reading image %s\n", imagepath); // Data read from the header of the BMP file unsigned char header[54]; unsigned int dataPos; unsigned int imageSize; unsigned int width, height; // Actual RGB data unsigned char * data; // Open the file FILE * file = fopen(imagepath,"rb"); if (!file) {printf("%s could not be opened. Are you in the right directory ? Don't forget to read the FAQ !\n", imagepath); getchar(); return 0;} // Read the header, i.e. the 54 first bytes // If less than 54 bytes are read, problem if ( fread(header, 1, 54, file)!=54 ){ printf("Not a correct BMP file\n"); return 0; } // A BMP files always begins with "BM" if ( header[0]!='B' || header[1]!='M' ){ printf("Not a correct BMP file\n"); return 0; } // Make sure this is a 24bpp file if ( *(int*)&(header[0x1E])!=0 ) {printf("Not a correct BMP file\n"); return 0;} if ( *(int*)&(header[0x1C])!=24 ) {printf("Not a correct BMP file\n"); return 0;} // Read the information about the image dataPos = *(int*)&(header[0x0A]); imageSize = *(int*)&(header[0x22]); width = *(int*)&(header[0x12]); height = *(int*)&(header[0x16]); // Some BMP files are misformatted, guess missing information if (imageSize==0) imageSize=width*height*3; // 3 : one byte for each Red, Green and Blue component if (dataPos==0) dataPos=54; // The BMP header is done that way // Create a buffer data = new unsigned char [imageSize]; // Read the actual data from the file into the buffer fread(data,1,imageSize,file); // Everything is in memory now, the file wan be closed fclose (file); // Create one OpenGL texture GLuint textureID; glGenTextures(1, &textureID); // "Bind" the newly created texture : all future texture functions will modify this texture glBindTexture(GL_TEXTURE_2D, textureID); // Give the image to OpenGL glTexImage2D(GL_TEXTURE_2D, 0,GL_RGB, width, height, 0, GL_BGR, GL_UNSIGNED_BYTE, data); // OpenGL has now copied the data. Free our own version delete [] data; // Poor filtering, or ... //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); // ... nice trilinear filtering. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); glGenerateMipmap(GL_TEXTURE_2D); // Return the ID of the texture we just created return textureID; } // Since GLFW 3, glfwLoadTexture2D() has been removed. You have to use another texture loading library, // or do it yourself (just like loadBMP_custom and loadDDS) //GLuint loadTGA_glfw(const char * imagepath){ // // // Create one OpenGL texture // GLuint textureID; // glGenTextures(1, &textureID); // // // "Bind" the newly created texture : all future texture functions will modify this texture // glBindTexture(GL_TEXTURE_2D, textureID); // // // Read the file, call glTexImage2D with the right parameters // glfwLoadTexture2D(imagepath, 0); // // // Nice trilinear filtering. // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); // glGenerateMipmap(GL_TEXTURE_2D); // // // Return the ID of the texture we just created // return textureID; //} #define FOURCC_DXT1 0x31545844 // Equivalent to "DXT1" in ASCII #define FOURCC_DXT3 0x33545844 // Equivalent to "DXT3" in ASCII #define FOURCC_DXT5 0x35545844 // Equivalent to "DXT5" in ASCII GLuint loadDDS(const char * imagepath){ unsigned char header[124]; FILE *fp; /* try to open the file */ fp = fopen(imagepath, "rb"); if (fp == NULL){ printf("%s could not be opened. Are you in the right directory ? Don't forget to read the FAQ !\n", imagepath); getchar(); return 0; } /* verify the type of file */ char filecode[4]; fread(filecode, 1, 4, fp); if (strncmp(filecode, "DDS ", 4) != 0) { fclose(fp); return 0; } /* get the surface desc */ fread(&header, 124, 1, fp); unsigned int height = *(unsigned int*)&(header[8 ]); unsigned int width = *(unsigned int*)&(header[12]); unsigned int linearSize = *(unsigned int*)&(header[16]); unsigned int mipMapCount = *(unsigned int*)&(header[24]); unsigned int fourCC = *(unsigned int*)&(header[80]); unsigned char * buffer; unsigned int bufsize; /* how big is it going to be including all mipmaps? */ bufsize = mipMapCount > 1 ? linearSize * 2 : linearSize; buffer = (unsigned char*)malloc(bufsize * sizeof(unsigned char)); fread(buffer, 1, bufsize, fp); /* close the file pointer */ fclose(fp); unsigned int components = (fourCC == FOURCC_DXT1) ? 3 : 4; unsigned int format; switch(fourCC) { case FOURCC_DXT1: format = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT; break; case FOURCC_DXT3: format = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT; break; case FOURCC_DXT5: format = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT; break; default: free(buffer); return 0; } // Create one OpenGL texture GLuint textureID; glGenTextures(1, &textureID); // "Bind" the newly created texture : all future texture functions will modify this texture glBindTexture(GL_TEXTURE_2D, textureID); glPixelStorei(GL_UNPACK_ALIGNMENT,1); unsigned int blockSize = (format == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT) ? 8 : 16; unsigned int offset = 0; /* load the mipmaps */ for (unsigned int level = 0; level < mipMapCount && (width || height); ++level) { unsigned int size = ((width+3)/4)*((height+3)/4)*blockSize; glCompressedTexImage2D(GL_TEXTURE_2D, level, format, width, height, 0, size, buffer + offset); offset += size; width /= 2; height /= 2; // Deal with Non-Power-Of-Two textures. This code is not included in the webpage to reduce clutter. if(width < 1) width = 1; if(height < 1) height = 1; } free(buffer); return textureID; }
5.common/texture.hpp
#ifndef TEXTURE_HPP #define TEXTURE_HPP // Load a .BMP file using our custom loader GLuint loadBMP_custom(const char * imagepath); //// Since GLFW 3, glfwLoadTexture2D() has been removed. You have to use another texture loading library, //// or do it yourself (just like loadBMP_custom and loadDDS) //// Load a .TGA file using GLFW's own loader //GLuint loadTGA_glfw(const char * imagepath); // Load a .DDS file using GLFW's own loader GLuint loadDDS(const char * imagepath); #endif
6.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 vec2 vertexUV; // Output data ; will be interpolated for each fragment. out vec2 UV; // 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); // UV of the vertex. No special space for this one. UV = vertexUV; }
7.shaders/TextureFragmentShader.fragmentshader
#version 330 core // Interpolated values from the vertex shaders in vec2 UV; // Ouput data out vec3 color; // Values that stay constant for the whole mesh. uniform sampler2D myTextureSampler; void main(){ // Output color = color of the texture at the specified UV color = texture( myTextureSampler, UV ).rgb; }
