OpenGL使用矩阵进行平移旋转和缩放

#include <glad/glad.h> #include <GLFW/glfw3.h> #include "shader.h" #include <iostream> #include <glm/glm.hpp> #include <glm/gtc/matrix_transform.hpp> #include <glm/gtc/type_ptr.hpp> #define STB_IMAGE_IMPLEMENTATION #include "stb_image.h" 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(void) { //初始化glfw并创建窗口 //------------------- glfwInit(); glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); GLFWwindow * window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "window", NULL, NULL); if (window == NULL) { std::cout << "Failed to create GLFW window" << std::endl; glfwTerminate(); return -1; } glfwMakeContextCurrent(window); glfwSetFramebufferSizeCallback(window, framebuffer_size_callback); //初始化GLAD //-------- if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) { std::cout << "Failed to initialize GLAD" << std::endl; return -1; } //创建着色器 //--------- Shader ourShader("D:\\OpenGL\\Project1\\4.1.texture.vs", "D:\\OpenGL\\Project1\\4.1.texture.fs"); //设置顶点坐标，颜色，纹理坐标 //-------- float vertices[] = { // ---- 位置 ---- - 纹理坐标 - 0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f, -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f }; //设置EBO索引 unsigned int indices[] = { 0, 1, 3, // 第一个三角形 1, 2, 3 // 第二个三角形 }; 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); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0); glEnableVertexAttribArray(0); glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float))); glEnableVertexAttribArray(1); unsigned int texture1, texture2; glGenTextures(1, &texture1); glBindTexture(GL_TEXTURE_2D, texture1); 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_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); //生成 int width, height, nrChannels; stbi_set_flip_vertically_on_load(true); unsigned char * data = stbi_load("D:\\OpenGL\\Project1\\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); glGenTextures(1, &texture2); glBindTexture(GL_TEXTURE_2D, texture2); 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_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); data = stbi_load("D:\\OpenGL\\Project1\\awesomeface.png", &width, &height, &nrChannels, 0); if (data) { 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); ourShader.use(); ourShader.setInt("texture1", 0); ourShader.setInt("texture2", 1); while (!glfwWindowShouldClose(window)) { processInput(window); glClearColor(0.2f, 0.3f, 0.3f, 1.0f); glClear(GL_COLOR_BUFFER_BIT); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture1); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texture2); glm::mat4 transform = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first transform = glm::translate(transform, glm::vec3(0.5f, -0.5f, 0.0f)); transform = glm::rotate(transform, (float)glfwGetTime(), glm::vec3(0.0f, 0.0f, 1.0f)); unsigned int transformLoc = glGetUniformLocation(ourShader.ID, "transform"); glUniformMatrix4fv(transformLoc, 1, GL_FALSE, glm::value_ptr(transform)); glBindVertexArray(VAO); glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0); transform = glm::mat4(1.0f); // reset it to identity matrix transform = glm::translate(transform, glm::vec3(-0.5f, 0.5f, 0.0f)); float scaleAmount = sin(glfwGetTime()); transform = glm::scale(transform, glm::vec3(scaleAmount, scaleAmount, scaleAmount)); glUniformMatrix4fv(transformLoc, 1, GL_FALSE, glm::value_ptr(transform)); //第一个参数是uniform的位置值，第二个参数是矩阵的数量，第三个参数是否进行置换，这里不需要，最后一个参数是矩阵数据 //GLM并不是把它们的矩阵储存为OpenGL所希望接受的那种，因此我们要先用GLM的自带的函数value_ptr来变换这些数据。 glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0); glfwSwapBuffers(window); glfwPollEvents(); } glDeleteVertexArrays(1, &VAO); glDeleteBuffers(1, &VBO); glDeleteBuffers(1, &EBO); glfwTerminate(); return 0; } void processInput(GLFWwindow *window) { if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) glfwSetWindowShouldClose(window, true); } void framebuffer_size_callback(GLFWwindow* window, int width, int height) { glViewport(0, 0, width, height); }

顶点着色器

#version 330 core layout (location = 0) in vec3 aPos; layout (location = 1) in vec2 aTexCoord; out vec2 TexCoord; uniform mat4 transform; void main() { gl_Position = transform * vec4(aPos, 1.0); TexCoord = vec2(aTexCoord.x, aTexCoord.y); }

片元着色器

#version 330 core out vec4 FragColor; in vec2 TexCoord; // texture samplers uniform sampler2D texture1; uniform sampler2D texture2; void main() { // linearly interpolate between both textures (80% container, 20% awesomeface) FragColor = mix(texture(texture1, TexCoord), texture(texture2, TexCoord), 0.2); }