C++ OpenGL旋转立方体
代码骑士 人气:01、Z-缓冲
//开启深度测试 glEnable(GL_DEPTH_TEST);
2、GLM库函数
3、PVM矩阵
4、PVM矩阵的使用
我们需要引入GLM函数库的头文件:
#include<glm/glm.hpp> #include<glm/gtc/matrix_transform.hpp> #include<glm/gtc/type_ptr.hpp>
设置vew矩阵的相关参数:
//相机参数 glm::vec3 camera_position = glm::vec3(0.0f, 0.0f, 3.0f); //摄像机位置 glm::vec3 camera_front = glm::vec3(0.0f, 0.0f, -1.0f); //摄像机方向 glm::vec3 camera_up = glm::vec3(0.0f, 1.0f, 0.0f); //摄像机上向量
设置project矩阵视野fov:
float fov = 45.0f;
// Transform坐标变换矩阵 glm::mat4 model(1);//model矩阵,局部坐标变换至世界坐标 model = glm::translate(model, glm::vec3(0.0,0.0,0.0)); model = glm::rotate(model, (float)glfwGetTime(), glm::vec3(0.5f, 1.0f, 0.0f)); model = glm::scale(model, glm::vec3(1.0f,1.0f,1.0f));
glm::mat4 view(1);//view矩阵,世界坐标变换至观察坐标系 view = glm::lookAt(camera_position, camera_position + camera_front, camera_up);
glm::mat4 projection(1);//projection矩阵,投影矩阵 projection = glm::perspective(glm::radians(fov), (float)screen_width / screen_height, 0.1f, 100.0f);
int model_location = glGetUniformLocation(shader.ID, "model"); //获取着色器内某个参数的位置
glUniformMatrix4fv(model_location, 1, GL_FALSE, glm::value_ptr(model));//写入参数值
gl_Position=projection*view*model*vec4(aPos,1.0);
5、工程文件结构
shader.h
#ifndef __SHADER_H__ #define __SHADER_H__ #include <glad/glad.h> #include <glm/glm.hpp> #include <glm/gtc/type_ptr.hpp> #include "string" class Shader { public: unsigned int ID; Shader(const GLchar* vertex_shader_path, const GLchar* fragment_shader_path); ~Shader(); void Use(); void SetBool(const std::string &name, bool value) const; void SetInt(const std::string &name, int value) const; void SetFloat(const std::string &name, float value) const; void SetVec2(const std::string &name, const glm::vec2 &value) const; void SetVec2(const std::string &name, float x, float y) const; void SetVec3(const std::string &name, const glm::vec3 &value) const; void SetVec3(const std::string &name, float x, float y, float z) const; void SetVec4(const std::string &name, const glm::vec4 &value) const; void SetVec4(const std::string &name, float x, float y, float z, float w) const; void SetMat2(const std::string &name, const glm::mat2 &value) const; void SetMat3(const std::string &name, const glm::mat3 &value) const; void SetMat4(const std::string &name, const glm::mat4 &value) const; private: int GetShaderFromFile(const GLchar* vertex_shader_path, const GLchar* fragment_shader_path, std::string *vertex_shader_code, std::string *fragment_shader_code); int LinkShader(const char* vertex_shader_code, const char* fragment_shader_code); int GetUniform(const std::string &name) const; void CheckCompileErrors(GLuint shader, std::string type); }; #endif // !__SHADER_H__ #ifndef __SHADER_H__ #define __SHADER_H__ #include <glad/glad.h> #include <glm/glm.hpp> #include <glm/gtc/type_ptr.hpp> #include "string" class Shader { public: unsigned int ID; Shader(const GLchar* vertex_shader_path, const GLchar* fragment_shader_path); ~Shader(); void Use(); void SetBool(const std::string &name, bool value) const; void SetInt(const std::string &name, int value) const; void SetFloat(const std::string &name, float value) const; void SetVec2(const std::string &name, const glm::vec2 &value) const; void SetVec2(const std::string &name, float x, float y) const; void SetVec3(const std::string &name, const glm::vec3 &value) const; void SetVec3(const std::string &name, float x, float y, float z) const; void SetVec4(const std::string &name, const glm::vec4 &value) const; void SetVec4(const std::string &name, float x, float y, float z, float w) const; void SetMat2(const std::string &name, const glm::mat2 &value) const; void SetMat3(const std::string &name, const glm::mat3 &value) const; void SetMat4(const std::string &name, const glm::mat4 &value) const; private: int GetShaderFromFile(const GLchar* vertex_shader_path, const GLchar* fragment_shader_path, std::string *vertex_shader_code, std::string *fragment_shader_code); int LinkShader(const char* vertex_shader_code, const char* fragment_shader_code); int GetUniform(const std::string &name) const; void CheckCompileErrors(GLuint shader, std::string type); }; #endif // !__SHADER_H__ #ifndef __SHADER_H__ #define __SHADER_H__ #include <glad/glad.h> #include <glm/glm.hpp> #include <glm/gtc/type_ptr.hpp> #include "string" class Shader { public: unsigned int ID; Shader(const GLchar* vertex_shader_path, const GLchar* fragment_shader_path); ~Shader(); void Use(); void SetBool(const std::string &name, bool value) const; void SetInt(const std::string &name, int value) const; void SetFloat(const std::string &name, float value) const; void SetVec2(const std::string &name, const glm::vec2 &value) const; void SetVec2(const std::string &name, float x, float y) const; void SetVec3(const std::string &name, const glm::vec3 &value) const; void SetVec3(const std::string &name, float x, float y, float z) const; void SetVec4(const std::string &name, const glm::vec4 &value) const; void SetVec4(const std::string &name, float x, float y, float z, float w) const; void SetMat2(const std::string &name, const glm::mat2 &value) const; void SetMat3(const std::string &name, const glm::mat3 &value) const; void SetMat4(const std::string &name, const glm::mat4 &value) const; private: int GetShaderFromFile(const GLchar* vertex_shader_path, const GLchar* fragment_shader_path, std::string *vertex_shader_code, std::string *fragment_shader_code); int LinkShader(const char* vertex_shader_code, const char* fragment_shader_code); int GetUniform(const std::string &name) const; void CheckCompileErrors(GLuint shader, std::string type); }; #endif // !__SHADER_H__
shader.cpp
#include "Shader.h" #include "fstream" #include "sstream" #include "iostream" Shader::Shader(const GLchar* vertex_shader_path, const GLchar* fragment_shader_path) { std::string vertex_shader_code; std::string fragment_shader_code; if (GetShaderFromFile(vertex_shader_path, fragment_shader_path, &vertex_shader_code, &fragment_shader_code)) { return; } if (LinkShader(vertex_shader_code.c_str(), fragment_shader_code.c_str())) { return; } } Shader::~Shader() { } void Shader::Use() { glUseProgram(ID); } void Shader::SetBool(const std::string &name, bool value) const { SetInt(name, (int)value); } void Shader::SetInt(const std::string &name, int value) const { glUniform1i(GetUniform(name), value); } void Shader::SetFloat(const std::string &name, float value) const { glUniform1f(GetUniform(name), value); } void Shader::SetVec2(const std::string &name, float x, float y) const { glUniform2f(GetUniform(name), x, y); } void Shader::SetVec2(const std::string &name, const glm::vec2 &value) const { SetVec2(name, value.x, value.y); } void Shader::SetVec3(const std::string &name, float x, float y, float z) const { glUniform3f(GetUniform(name), x, y, z); } void Shader::SetVec3(const std::string &name, const glm::vec3 &value) const { SetVec3(name, value.x, value.y, value.z); } void Shader::SetVec4(const std::string &name, float x, float y, float z, float w) const { glUniform4f(GetUniform(name), x, y, z, w); } void Shader::SetVec4(const std::string &name, const glm::vec4 &value) const { SetVec4(name, value.x, value.y, value.z, value.w); } void Shader::SetMat2(const std::string &name, const glm::mat2 &value) const { glUniformMatrix2fv(GetUniform(name), 1, GL_FALSE, &value[0][0]); } void Shader::SetMat3(const std::string &name, const glm::mat3 &value) const { glUniformMatrix3fv(GetUniform(name), 1, GL_FALSE, &value[0][0]); } void Shader::SetMat4(const std::string &name, const glm::mat4 &value) const { glUniformMatrix4fv(GetUniform(name), 1, GL_FALSE, &value[0][0]); } int Shader::GetShaderFromFile(const GLchar* vertex_shader_path, const GLchar* fragment_shader_path, std::string *vertex_shader_code, std::string *fragment_shader_code) { std::ifstream vertex_shader_file; std::ifstream fragment_shader_file; vertex_shader_file.exceptions(std::ifstream::badbit | std::ifstream::failbit); fragment_shader_file.exceptions(std::ifstream::badbit | std::ifstream::failbit); try { vertex_shader_file.open(vertex_shader_path); fragment_shader_file.open(fragment_shader_path); std::stringstream vertex_shader_stream, fragment_shader_stream; vertex_shader_stream << vertex_shader_file.rdbuf(); fragment_shader_stream << fragment_shader_file.rdbuf(); vertex_shader_file.close(); fragment_shader_file.close(); *vertex_shader_code = vertex_shader_stream.str(); *fragment_shader_code = fragment_shader_stream.str(); } catch (std::ifstream::failure e) { std::cout << "Load Shader File Error!" << std::endl; return -1; } return 0; } int Shader::LinkShader(const char* vertex_shader_code, const char* fragment_shader_code) { int vertex_shader = glCreateShader(GL_VERTEX_SHADER); glShaderSource(vertex_shader, 1, &vertex_shader_code, NULL); glCompileShader(vertex_shader); CheckCompileErrors(vertex_shader, "VERTEX"); int fragment_shader = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(fragment_shader, 1, &fragment_shader_code, NULL); glCompileShader(fragment_shader); CheckCompileErrors(fragment_shader, "FRAGMENT"); this->ID = glCreateProgram(); glAttachShader(ID, vertex_shader); glAttachShader(ID, fragment_shader); glLinkProgram(ID); CheckCompileErrors(ID, "PROGRAM"); glDeleteShader(vertex_shader); glDeleteShader(fragment_shader); return 0; } int Shader::GetUniform(const std::string &name) const { int position = glGetUniformLocation(ID, name.c_str()); if (position == -1) { std::cout << "uniform " << name << " set failed!" << std::endl; } return position; } void Shader::CheckCompileErrors(GLuint shader, std::string type) { GLint success; GLchar infoLog[512]; if (type == "PROGRAM") { glGetProgramiv(shader, GL_LINK_STATUS, &success); if (!success) { glGetProgramInfoLog(shader, 512, NULL, infoLog); std::cout << "ERROR::PROGRAM_LINKING_ERROR!\n" << infoLog << std::endl; } } else { glGetShaderiv(shader, GL_COMPILE_STATUS, &success); if (!success) { glGetShaderInfoLog(shader, 512, NULL, infoLog); std::cout << "ERROR::SHADER::" << type << "::COMPILATION_FAILED\n" << infoLog << std::endl; } } }
main.cpp
//总体流程 //1. 初始化并创建窗口 //2. 加载立方体顶点VAOVBO以及着色器并开启深度测试 //3. 进入主循环清除缓冲 //4. 使用立方体着色器,构造并传入pvm矩阵,绘制 //5. 循环结束,释放VAOVBO #include <iostream> #include "glad/glad.h" #include "GLFW/glfw3.h" #include "glm/glm.hpp" #include "glm/gtc/matrix_transform.hpp" #include "glm/gtc/type_ptr.hpp" #include "shader.h" const float vertices[] = { //立方体数组 -0.5f, -0.5f, -0.5f, 1.0f,0.0f,0.0f, 0.5f, -0.5f, -0.5f, 1.0f,0.0f,0.0f, 0.5f, 0.5f, -0.5f, 1.0f,0.0f,0.0f, 0.5f, 0.5f, -0.5f, 1.0f,0.0f,0.0f, -0.5f, 0.5f, -0.5f, 1.0f,0.0f,0.0f, -0.5f, -0.5f, -0.5f, 1.0f,0.0f,0.0f, -0.5f, -0.5f, 0.5f, 0.0f,1.0f,0.0f, 0.5f, -0.5f, 0.5f, 0.0f,1.0f,0.0f, 0.5f, 0.5f, 0.5f, 0.0f,1.0f,0.0f, 0.5f, 0.5f, 0.5f, 0.0f,1.0f,0.0f, -0.5f, 0.5f, 0.5f, 0.0f,1.0f,0.0f, -0.5f, -0.5f, 0.5f, 0.0f,1.0f,0.0f, -0.5f, 0.5f, 0.5f, 0.0f,0.0f,1.0f, -0.5f, 0.5f, -0.5f, 0.0f,0.0f,1.0f, -0.5f, -0.5f, -0.5f, 0.0f,0.0f,1.0f, -0.5f, -0.5f, -0.5f, 0.0f,0.0f,1.0f, -0.5f, -0.5f, 0.5f, 0.0f,0.0f,1.0f, -0.5f, 0.5f, 0.5f, 0.0f,0.0f,1.0f, 0.5f, 0.5f, 0.5f, 0.5f,0.0f,0.0f, 0.5f, 0.5f, -0.5f, 0.5f,0.0f,0.0f, 0.5f, -0.5f, -0.5f, 0.5f,0.0f,0.0f, 0.5f, -0.5f, -0.5f, 0.5f,0.0f,0.0f, 0.5f, -0.5f, 0.5f, 0.5f,0.0f,0.0f, 0.5f, 0.5f, 0.5f, 0.5f,0.0f,0.0f, -0.5f, -0.5f, -0.5f, 0.0f,0.5f,0.0f, 0.5f, -0.5f, -0.5f, 0.0f,0.5f,0.0f, 0.5f, -0.5f, 0.5f, 0.0f,0.5f,0.0f, 0.5f, -0.5f, 0.5f, 0.0f,0.5f,0.0f, -0.5f, -0.5f, 0.5f, 0.0f,0.5f,0.0f, -0.5f, -0.5f, -0.5f, 0.0f,0.5f,0.0f, -0.5f, 0.5f, -0.5f, 0.0f,0.0f,0.5f, 0.5f, 0.5f, -0.5f, 0.0f,0.0f,0.5f, 0.5f, 0.5f, 0.5f, 0.0f,0.0f,0.5f, 0.5f, 0.5f, 0.5f, 0.0f,0.0f,0.5f, -0.5f, 0.5f, 0.5f, 0.0f,0.0f,0.5f, -0.5f, 0.5f, -0.5f, 0.0f,0.0f,0.5f }; float screen_width = 1280.0f; //窗口宽度 float screen_height = 720.0f; //窗口高度 //相机参数 glm::vec3 camera_position = glm::vec3(0.0f, 0.0f, 3.0f); //摄像机位置 glm::vec3 camera_front = glm::vec3(0.0f, 0.0f, -1.0f); //摄像机方向 glm::vec3 camera_up = glm::vec3(0.0f, 1.0f, 0.0f); //摄像机上向量 //视野 float fov = 45.0f; int main() { // 初始化GLFW glfwInit(); // 初始化GLFW glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); // OpenGL版本为3.3,主次版本号均设为3 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 使用核心模式(无需向后兼容性) glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // 如果使用的是Mac OS X系统,需加上这行 glfwWindowHint(GLFW_RESIZABLE, FALSE); // 不可改变窗口大小 // 创建窗口(宽、高、窗口名称) auto window = glfwCreateWindow(screen_width, screen_height, "Cube", nullptr, nullptr); if (window == nullptr) { // 如果窗口创建失败,输出Failed to Create OpenGL Context std::cout << "Failed to Create OpenGL Context" << std::endl; glfwTerminate(); return -1; } glfwMakeContextCurrent(window); // 将窗口的上下文设置为当前线程的主上下文 // 初始化GLAD,加载OpenGL函数指针地址的函数 if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) { std::cout << "Failed to initialize GLAD" << std::endl; return -1; } // 指定当前视口尺寸(前两个参数为左下角位置,后两个参数是渲染窗口宽、高) glViewport(0, 0, screen_width, screen_height); Shader shader("res/shader/task-cube.vs", "res/shader/task-cube.fs");//加载着色器 // 生成并绑定VAO和VBO GLuint vertex_array_object; // == VAO glGenVertexArrays(1, &vertex_array_object); glBindVertexArray(vertex_array_object); GLuint vertex_buffer_object; // == VBO glGenBuffers(1, &vertex_buffer_object); glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer_object); // 将顶点数据绑定至当前默认的缓冲中 glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); // 设置顶点属性指针 glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0); glEnableVertexAttribArray(0); glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float))); glEnableVertexAttribArray(1); glEnable(GL_DEPTH_TEST); // Render loop主循环 while (!glfwWindowShouldClose(window)) { //进入主循环,清理颜色缓冲深度缓冲 glClearColor(0.0f, 0.34f, 0.57f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);//清理颜色缓冲和深度缓冲 shader.Use(); // Transform坐标变换矩阵 glm::mat4 model(1);//model矩阵,局部坐标变换至世界坐标 model = glm::translate(model, glm::vec3(0.0,0.0,0.0)); model = glm::rotate(model, (float)glfwGetTime(), glm::vec3(0.5f, 1.0f, 0.0f)); model = glm::scale(model, glm::vec3(1.0f,1.0f,1.0f)); glm::mat4 view(1);//view矩阵,世界坐标变换至观察坐标系 view = glm::lookAt(camera_position, camera_position + camera_front, camera_up); glm::mat4 projection(1);//projection矩阵,投影矩阵 projection = glm::perspective(glm::radians(fov), (float)screen_width / screen_height, 0.1f, 100.0f); // 向着色器中传入参数 int model_location = glGetUniformLocation(shader.ID, "model"); //获取着色器内某个参数的位置 glUniformMatrix4fv(model_location, 1, GL_FALSE, glm::value_ptr(model));//写入参数值 int view_location = glGetUniformLocation(shader.ID, "view"); glUniformMatrix4fv(view_location, 1, GL_FALSE, glm::value_ptr(view)); int projection_location = glGetUniformLocation(shader.ID, "projection"); glUniformMatrix4fv(projection_location, 1, GL_FALSE, glm::value_ptr(projection)); //绘制 glBindVertexArray(vertex_array_object); glDrawArrays(GL_TRIANGLES, 0, 36); glBindVertexArray(0); glfwSwapBuffers(window); glfwPollEvents(); } //释放VAOVBO glDeleteVertexArrays(1, &vertex_array_object); glDeleteBuffers(1, &vertex_buffer_object); // 清理所有的资源并正确退出程序 glfwTerminate(); return 0; }
输出结果:
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