glew，glfw实现最新的opengl-学习笔记4实现纹理

这篇文章是利用着色器给画的图形添加上纹理，参照着教程教程链接书写的，可能上面的源代码点击失效，到这个教程的英文版去找源码链接  文中的加载图片和纹理的路径使用的绝对路径，所以要根绝自己的情况更改代码中的路径  源代码点击打开链接

头文件shader.h

#ifndef SHADER_H#define SHADER_H#include<string>#include<fstream>#include<sstream>#include<iostream>#include<GL/glew.h>using namespace std;class Shader{public://程序的IDGLuint Program;//读取渲染程序并创建ShaderShader(const GLchar * vertexSourcePath,const GLchar *fragmentSource);{//1.从文件路径获得vertex/fragment源码string vertexCode;string fragmentCode;try{//打开文件Open filesifstream vShaderFile(vertexPath);ifstream fShaderFile(fragmentPath);stringstream vShaderStream,fShaderStream;//读取文件缓冲到流、vShaderStream<<vShaderFile.rdbuf();fShaderStream<<fShaderFile.rdbuf();//关闭文件句柄vShaderFile.close();fShaderFile.close();//将流转为GLchar数组 vertexCode = vShaderStream.str();         fragmentCode = fShaderStream.str(); }catch(std::exception e)     {         std::cout << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ" << std::endl;      }const GLchar* vShaderCode = vertexCode.c_str();        const GLchar * fShaderCode = fragmentCode.c_str();        // 2.编译着色器        GLuint vertex, fragment;        GLint success;        GLchar infoLog[512];        // 顶点着色器        vertex = glCreateShader(GL_VERTEX_SHADER);        glShaderSource(vertex, 1, &vShaderCode, NULL);        glCompileShader(vertex);        // 打印着色器是否错误        glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);        if (!success)        {            glGetShaderInfoLog(vertex, 512, NULL, infoLog);            std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;        }        // 片段着色器        fragment = glCreateShader(GL_FRAGMENT_SHADER);        glShaderSource(fragment, 1, &fShaderCode, NULL);        glCompileShader(fragment);        // 打印是否有任何错误        glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);        if (!success)        {            glGetShaderInfoLog(fragment, 512, NULL, infoLog);            std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;        }        // 着色器程序        this->Program = glCreateProgram();        glAttachShader(this->Program, vertex);        glAttachShader(this->Program, fragment);        glLinkProgram(this->Program);        // 打印是否有错误        glGetProgramiv(this->Program, GL_LINK_STATUS, &success);        if (!success)        {            glGetProgramInfoLog(this->Program, 512, NULL, infoLog);            std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;        }        // 删除着色器程序        glDeleteShader(vertex);        glDeleteShader(fragment);}//使用Programvoid Use();{glUseProgram(this->Program);}}#endif

实现texture.cpp

<pre name="code" class="cpp">#include<iostream>//GLEW#define GLEW_STATIC#include <GL/glew.h>// GLFW#include <GLFW/glfw3.h>#pragma comment(lib,"FreeImage.lib")// Other Libs#include<FreeImage.h>#include<Shader.h>using namespace std;void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);// Window 尺寸const GLuint WIDTH = 800, HEIGHT = 600;int main(){//I初始化GLFWglfwInit(); FreeImage_Initialise(TRUE);//初始化FreeImage//设置全部GLFW要求的设置 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);//创造一个GLFWwindow 项目 我们可以使用GLFW的功能GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", nullptr, nullptr);    glfwMakeContextCurrent(window);//设置回调函数的注册glfwSetKeyCallback(window, key_callback);//glew设置为true  让glew知道使用现在的方法去恢复指针和扩展glewExperimental = GL_TRUE;//初始化glew 去设置opengl功能指针 glewInit(); //定义视图的尺寸 glViewport(0, 0, WIDTH, HEIGHT);//定义和编译我们的着色器程序 Shader ourShader("D:/C语言/openglflew/shader1/shader.vs", "D:/C语言/openglflew/shader1/shader.frag"); //设置顶点数据（和缓冲）和属性指针  GLfloat vertices[] = {        // 位置          // 颜色           // 纹理坐标         0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 1.0f,   1.0f, 1.0f, // Top Right         0.5f, -0.5f, 0.0f,   1.0f, 1.0f, 1.0f,   1.0f, 0.0f, // Bottom Right        -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // Bottom Left        -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // 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);    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);    // 位置属性    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);    glEnableVertexAttribArray(0);    // 颜色属性    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));    glEnableVertexAttribArray(1);    // 纹理属性    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));    glEnableVertexAttribArray(2);    glBindVertexArray(0); // 解绑 VAO// Load image, create texture and generate mipmaps 加载图像并且创建纹理和产生编码   //image format    FREE_IMAGE_FORMAT fif = FIF_UNKNOWN;int width, height;FIBITMAP *dib(0);   // unsigned char* image = SOIL_load_image("container.jpg", &width, &height, 0, SOIL_LOAD_RGB);//1 获取图片格式FREE_IMAGE_FORMAT fifmt = FreeImage_GetFileType("D:/C语言/openglflew/wall.png", 0);//2 加载图片 if(FreeImage_FIFSupportsReading(fifmt))   dib = FreeImage_Load(fifmt, "D:/C语言/openglflew/wall.png",0);  printf("bit: %d\n", FreeImage_GetBPP(dib));//灰度  printf("type: %d\n",FreeImage_GetImageType(dib));//返回类型  printf("bit: %d\n",FreeImage_GetColorsUsed(dib));//调色板的大小  printf("bit: %d\n",FreeImage_GetDIBSize(dib));//大小    //if the image failed to load, return failure    if(!dib)        cout<<55<<endl;//3 转化为rgb 24色dib = FreeImage_ConvertTo24Bits(dib);//4 获取数据指针BYTE *pixels = (BYTE*)FreeImage_GetBits(dib);  width = FreeImage_GetWidth(dib); height = FreeImage_GetHeight(dib); cout<<"width:"<<width<<endl;  cout<<"height:"<<height<<endl;    // 加载和创建纹理    GLuint texture;    glGenTextures(1, &texture);    glBindTexture(GL_TEXTURE_2D, texture); // 设置为2D纹理    // Set the texture wrapping parameters  设置纹理包装参数    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);// Set texture wrapping to GL_REPEAT (usually basic wrapping method)    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);    // Set texture filtering parameters  设置纹理过滤的参数    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);          glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_BGR_EXT, GL_UNSIGNED_BYTE, pixels);   FreeImage_Unload(dib);   FreeImage_DeInitialise();    glGenerateMipmap(GL_TEXTURE_2D);    glBindTexture(GL_TEXTURE_2D, 0); // 解除绑定的纹理// Game loop    while (!glfwWindowShouldClose(window))    {        // Check if any events have been activiated (key pressed, mouse moved etc.) and call corresponding response functions        glfwPollEvents();        // Render  渲染        // Clear the colorbuffer 清理颜色缓存        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);        glClear(GL_COLOR_BUFFER_BIT);        // Bind Texture 绑定纹理        glBindTexture(GL_TEXTURE_2D, texture);        // Activate shader 设置活动的着色器        ourShader.Use();                       // Draw container        glBindVertexArray(VAO);        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);    // Terminate GLFW, clearing any resources allocated by GLFW.    glfwTerminate();    return 0;}// Is called whenever a key is pressed/released via GLFWvoid key_callback(GLFWwindow* window, int key, int scancode, int action, int mode){    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)        glfwSetWindowShouldClose(window, GL_TRUE);}    

像素着色器shader.frag代码

#version 330 corein vec3 ourColor;in vec2 TexCoord;out vec4 color;uniform sampler2D ourTexture;//设置采样器void main(){  color = texture(ourTexture, TexCoord);//texture是采样函数第一个参数是纹理采样器。第二个参数是纹理坐标}

顶点着色器shder.vs代码

#version 330 corelayout (location = 0) in vec3 position;layout (location = 1) in vec3 color;layout (location = 2) in vec2 texCoord;out vec3 ourColor;out vec2 TexCoord;void main(){    gl_Position = vec4(position, 1.0f);    ourColor = color; TexCoord = texCoord;}

纹理照片

运行效果图