OpenGL——图象变换(简单的线性代数)
#include <glad/glad.h> #include <GLFW/glfw3.h> #include <assimp/config.h> #include <glm/glm.hpp> #include <glm/gtc/matrix_transform.hpp> #include <glm/gtc/type_ptr.hpp> #include "stb_image.h" #include "shader_s.h" #include <iostream> 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); // uncomment this statement to fix compilation on OS X #endif // glfw window creation // -------------------- GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL); glfwSetWindowPos(window, 700, 400); 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("shader.vs", "shader.fs"); // set up vertex data (and buffer(s)) and configure vertex attributes // ------------------------------------------------------------------ float vertices[] = { // positions // texture coords 0.5f, 0.5f, 0.0f, 1.0f, 1.0f, // top right 0.5f, -0.5f, 0.0f, 1.0f, 0.0f, // bottom right -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, // bottom left -0.5f, 0.5f, 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, 5 * sizeof(float), (void*)0); glEnableVertexAttribArray(0); // texture coord attribute glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float))); glEnableVertexAttribArray(1); // load and create a texture // ------------------------- unsigned int texture1, texture2; // texture 1 // --------- glGenTextures(1, &texture1); glBindTexture(GL_TEXTURE_2D, texture1); // 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 int width, height, nrChannels; stbi_set_flip_vertically_on_load(true); // tell stb_image.h to flip loaded texture's on the y-axis. unsigned char* data = stbi_load("image/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); // texture 2 // --------- 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("image/awesomeface.png", &width, &height, &nrChannels, 0); if (data) { // note that the awesomeface.png has transparency and thus an alpha channel, so make sure to tell OpenGL the data type is of GL_RGBA glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 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(); ourShader.setInt("texture1", 0); 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 textures on corresponding texture units glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture1); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texture2); // create transformations glm::mat4 trans = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first trans = glm::rotate(trans, (float)glfwGetTime(), glm::vec3(0.0, 0.0, 1.0)); std:: cout << glfwGetTime() << std::endl; //trans = glm::scale(trans, glm::vec3(0.5, 0.5, 0.5));//大小变化 // get matrix's uniform location and set matrix ourShader.use(); unsigned int transformLoc = glGetUniformLocation(ourShader.ID, "transform"); glUniformMatrix4fv(transformLoc, 1, GL_FALSE, glm::value_ptr(trans)); // render container 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); }