image.png
到这一讲稍微复杂点了，做个阶段性的总结，加深记忆
opengl工作流理解：
opengl实现渲染的套路有一定范式，把握两条主线：
opengl 工作流
项目目录：
项目目录
注意：1. 图片资源要放到代码同目录里加载才能成功 2.texture.vs和texture.fs源码在学习资料里通过点击跳转来获取
核心代码实现：
#include <glad/glad.h> #include <GLFW/glfw3.h>
#define STB_IMAGE_IMPLEMENTATION #include "stb_image.h"
#include "Shader.h" #include
void framebuffer_size_callback(GLFWwindow* window, int width, int height); void processInput(GLFWwindow *window);
// settings const unsigned int SCR_WIDTH = 800; const unsigned int SCR_HEIGHT = 600;
int main() { // glfw: initialize and configure // ------------------------------ glfwInit(); glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); #ifdef APPLE glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); #endif
// glfw window creation // -------------------- GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL); if (window == NULL) { std::cout << "Failed to create GLFW window" << std::endl; glfwTerminate(); return -1; } glfwMakeContextCurrent(window); glfwSetFramebufferSizeCallback(window, framebuffer_size_callback); // glad: load all OpenGL function pointers // --------------------------------------- if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) { std::cout << "Failed to initialize GLAD" << std::endl; return -1; } // build and compile our shader zprogram // ------------------------------------ Shader ourShader("4.1.texture.vs", "4.1.texture.fs"); // set up vertex data (and buffer(s)) and configure vertex attributes // ------------------------------------------------------------------ float vertices[] = { // positions // colors // texture coords 0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // top right 0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 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 }; unsigned int indices[] = { 0, 1, 3, // first triangle 1, 2, 3 // second triangle }; unsigned int 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); // position attribute glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0); glEnableVertexAttribArray(0); // color attribute glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float))); glEnableVertexAttribArray(1); // texture coord attribute glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float))); glEnableVertexAttribArray(2); // load and create a texture // ------------------------- unsigned int texture1, texture2; glGenTextures(1, &texture1); glBindTexture(GL_TEXTURE_2D, texture1); // all upcoming GL_TEXTURE_2D operations now have effect on this texture object // set the texture wrapping parameters glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); // set texture wrapping to GL_REPEAT (default wrapping method) glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); // set texture filtering parameters glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // load image, create texture and generate mipmaps int width, height, nrChannels; // The FileSystem::getPath(...) is part of the GitHub repository so we can find files on any IDE/platform; replace it with your own image path.// 测试代码，判断文件是否存在，这里一开始写绝对路径，找不到文件，把文件拷贝到项目目录下才可以 // std::fstream _file; // _file.open("container.jpg", std::ios::in); // if (_file.is_open()) { // std::cout<<"打开成功"<<std::endl; // } else { // std::cout <<"打开失败"<< std::endl; // } // // return 0;
stbi_set_flip_vertically_on_load(true); unsigned char *data = stbi_load("container.jpg", &width, &height, &nrChannels, 0);// unsigned char *data = stbi_load("/Users/baidu/Downloads/container.jpg", &width, &height, &nrChannels, 0);
if (data) { glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data); glGenerateMipmap(GL_TEXTURE_2D); } else { std::cout << "Failed to load texture" << std::endl; } stbi_image_free(data); // texture2 glGenTextures(1, &texture2); glBindTexture(GL_TEXTURE_2D, texture2); // set the texture wrapping parameters glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); // set texture filtering parameters glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // load image, create texture and generate mipmaps data = stbi_load("awesomeface.png", &width, &height, &nrChannels, 0); if (data) { glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data); glGenerateMipmap(GL_TEXTURE_2D); } else { std::cout << "Failed to load texture" << std::endl; } stbi_image_free(data); // tell opengl for each sampler to which texture unit it belongs to (only has to be done once) ourShader.use(); // either set it manually like so: glUniform1i(glGetUniformLocation(ourShader.ID, "texture1"), 0); // or set it via the texture class ourShader.setInt("texture2", 1); // render loop // ----------- while (!glfwWindowShouldClose(window)) { // input // ----- processInput(window); // render // ------ glClearColor(0.2f, 0.3f, 0.3f, 1.0f); glClear(GL_COLOR_BUFFER_BIT); // bind Texture // bind textures on corresponding texture units glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture1); glActiveTexture(GL_TEXTURE1); // GL_TEXTURE2就不行 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); }
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