现代OpenGL自学----纹理测试

继续学习OpenGL。

#include <iostream>#include <glad\glad.h>#include <GLFW\glfw3.h>#define STB_IMAGE_IMPLEMENTATION#include "stb_image.h"#include <shader.h>using namespace std; //切记 如果2个纹理图片大小不一样 则会出现未知的错误！！！！！！！！！！void framebuffer_size_callback(GLFWwindow * window, int width, int height);void processInput(GLFWwindow * window);const unsigned int SCR_WIDTH = 800;const unsigned int SCR_HEIGHT = 600;int main(){    glfwInit();    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);    glfwWindowHint(GLFW_OPENGL_CORE_PROFILE, GLFW_OPENGL_PROFILE);    GLFWwindow * window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "111", NULL, NULL);    if (!window)    {        cout << "Error to create a window" << endl;        glfwTerminate();        return -1;    }    glfwMakeContextCurrent(window);    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))    {        cout << "Failed  to initialize GLAD" << endl;        return -1;    }    Shader ourshader("1.txt", "2.txt");    float vertices[] = {            0.5f, 0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   2.0f, 2.0f, // top right            0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   2.0f, 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, 2.0f  // top left         };    unsigned int indices[] = {        0, 1, 3,        1, 2, 3    };    unsigned int VAO, VBO, 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(float), (void*)0);    glEnableVertexAttribArray(0);    //颜色属性    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));    glEnableVertexAttribArray(1);    // 纹理属性    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));    glEnableVertexAttribArray(2);    unsigned int texture1, texture2;    glGenTextures(1, &texture1); //生成一个纹理数量,存储在texture1中    glBindTexture(GL_TEXTURE_2D, texture1);//绑定纹理    //纹理环绕    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);//二维的目标纹理,纹理轴为x(s即为x)轴,环绕方式为重复    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);//二维的目标纹理,纹理轴为y(t即为y)轴,环绕方式为重复    //纹理过滤    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);//二维的目标纹理,缩小纹理过滤选择线性过滤    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);//二维的目标纹理,放大纹理过滤选择邻近过滤    int width, width1, height, height1, nrChannels, nrChannels1;    stbi_set_flip_vertically_on_load(true); //翻转图像为正    unsigned char *data = stbi_load("container.jpg", &width, &height, &nrChannels, 0);//载入jpg图像,宽长通道都为此jpg图像的    if (data)    {        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data); //载入图片生成纹理        glGenerateMipmap(GL_TEXTURE_2D);//自动生成多级渐远纹理    }    else    {        std::cout << "Failed to load texture" << std::endl;    }    stbi_image_free(data);//释放图像内存    glGenTextures(1, &texture2);//生成一个纹理数量,存储在texture2中    glBindTexture(GL_TEXTURE_2D, texture2);//绑定纹理    //设置纹理环绕方式    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);    //设置纹理过滤方式    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);    unsigned char *data1 = stbi_load("awesomeface.png", &width1, &height1, &nrChannels1, 0);     if (data1)    {        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width1, height1, 0, GL_RGBA, GL_UNSIGNED_BYTE, data1);        glGenerateMipmap(GL_TEXTURE_2D);    }    else    {        std::cout << "Failed to load texture" << std::endl;    }    stbi_image_free(data1);    ourshader.use();//启用着色器    glUniform1i(glGetUniformLocation(ourshader.ID, "texture2"), 0);//使用glUniform之前要启用着色器 用glGetUniformLocation查询uniform texture1的位置值    // or set it via the texture class    ourshader.setInt("texture2", 1);    while (!glfwWindowShouldClose(window))    {        // input        // -----        processInput(window);        // render        // ------        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);        glClear(GL_COLOR_BUFFER_BIT);        // bind textures on corresponding texture units        glActiveTexture(GL_TEXTURE0);        glBindTexture(GL_TEXTURE_2D, texture1);        glActiveTexture(GL_TEXTURE1);        glBindTexture(GL_TEXTURE_2D, texture2);        // render container        ourshader.use();        glBindVertexArray(VAO);        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)        // -------------------------------------------------------------------------------        glfwSwapBuffers(window);        glfwPollEvents();    }    // optional: de-allocate all resources once they've outlived their purpose:    // ------------------------------------------------------------------------    glDeleteVertexArrays(1, &VAO);    glDeleteBuffers(1, &VBO);    glDeleteBuffers(1, &EBO);    // glfw: terminate, clearing all previously allocated GLFW resources.    // ------------------------------------------------------------------    glfwTerminate();    return 0;}// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly// ---------------------------------------------------------------------------------------------------------void processInput(GLFWwindow *window){    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)        glfwSetWindowShouldClose(window, true);}// glfw: whenever the window size changed (by OS or user resize) this callback function executes// ---------------------------------------------------------------------------------------------void framebuffer_size_callback(GLFWwindow* window, int width, int height){    // make sure the viewport matches the new window dimensions; note that width and     // height will be significantly larger than specified on retina displays.    glViewport(0, 0, width, height);}