北京做网站的工作室,电脑网站进不去网页怎么办,局部翻新装修公司,网络公司网站开发GLM简单使用
glm是一个开源的对矩阵运算的库#xff0c;下载地址#xff1a; https://github.com/g-truc/glm/releases 直接包含其头文件即可使用#xff1a;
#include glad/glad.h//glad必须在glfw头文件之前包含
#include GLFW/glfw3.h
#include io…GLM简单使用
glm是一个开源的对矩阵运算的库下载地址 https://github.com/g-truc/glm/releases 直接包含其头文件即可使用
#include glad/glad.h//glad必须在glfw头文件之前包含
#include GLFW/glfw3.h
#include iostream
#define STB_IMAGE_IMPLEMENTATION
#include stb_image.h//GLM
#include glm/glm.hpp
#include glm/gtc/matrix_transform.hpp
#include glm/gtc/type_ptr.hpp
#define GLM_ENABLE_EXPERIMENTAL
#include glm/gtx/string_cast.hppvoid frameBufferSizeCallbakc(GLFWwindow* window, int width, int height)
{glViewport(0, 0, width, height);
}
void glfwKeyCallback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
}GLuint program 0;
GLuint vao 0;
GLuint texture 0;
glm::mat4 transform(1.0f);//4×4单位矩阵
//旋转
void doRotationTransform()
{//构建一个旋转矩阵绕着z轴旋转45度角//rotate函数用于生成旋转矩阵//bug1:rotate必须得到一个float类型的角度c的template//bug2:rotate函数接受的不是角度degree接收的弧度radians//注意点radians函数也是模板函数切记要传入float类型数据加f后缀transform glm::rotate(glm::mat4(1.0), glm::radians(90.f), glm::vec3(0.0, 0.0, 1.0));
}
//平移
void doTranslationTransform()
{transform glm::translate(glm::mat4(1.0), glm::vec3(0.5f, 0.0, 0.0));
}
//缩放
void doScaleTransform()
{//x缩放0.1y缩放0.5z不缩放transform glm::scale(glm::mat4(1.0), glm::vec3(0.1f, 0.5f, 1.0f));
}
//复合变换
void doTransform()
{glm::mat4 rotateMat glm::rotate(glm::mat4(1.0f), glm::radians(90.0f), glm::vec3(0.0, 0.0, 1.0));glm::mat4 translateMat glm::translate(glm::mat4(1.0f), glm::vec3(0.5f, 0.0f, 0.0f));//先旋转 再平移transform translateMat * rotateMat;//先平移 后旋转//transform rotateMat * translateMat;
}
float angle 0.0f;
void doRotation()
{angle 2.0f;//每一帧都会“重新”构建一个旋转矩阵transform glm::rotate(glm::mat4(1.0f), glm::radians(angle), glm::vec3(0.0f, 0.0f, 1.0f));;
}
void prepareVAO()
{//positionsfloat positions[] {-0.5f, -0.5f, 0.0f,0.5f, -0.5f, 0.0f,0.0f, 0.5f, 0.0f,};//颜色float colors[] {1.0f, 0.0f,0.0f,0.0f, 1.0f,0.0f,0.0f, 0.0f,1.0f};//索引unsigned int indices[] {0, 1, 2,};//uv坐标float uvs[] {0.0f, 0.0f,1.0f, 0.0f,0.5f, 1.0f,};//2 VBO创建GLuint posVbo 0;GLuint colorVbo 0;GLuint uvVbo 0;glGenBuffers(1, posVbo);glBindBuffer(GL_ARRAY_BUFFER, posVbo);glBufferData(GL_ARRAY_BUFFER, sizeof(positions), positions, GL_STATIC_DRAW);glGenBuffers(1, colorVbo);glBindBuffer(GL_ARRAY_BUFFER, colorVbo);glBufferData(GL_ARRAY_BUFFER, sizeof(colors), colors, GL_STATIC_DRAW);glGenBuffers(1, uvVbo);glBindBuffer(GL_ARRAY_BUFFER, uvVbo);glBufferData(GL_ARRAY_BUFFER, sizeof(uvs), uvs, GL_STATIC_DRAW);//3 EBO创建GLuint ebo 0;glGenBuffers(1, ebo);glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);//4 VAO创建vao 0;glGenVertexArrays(1, vao);glBindVertexArray(vao);//5 绑定vbo ebo 加入属性描述信息//5.1 加入位置属性描述信息glBindBuffer(GL_ARRAY_BUFFER, posVbo);glEnableVertexAttribArray(0);glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);//5.2 加入颜色属性描述信息glBindBuffer(GL_ARRAY_BUFFER, colorVbo);glEnableVertexAttribArray(1);glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);//5.3 加入uv属性描述数据glBindBuffer(GL_ARRAY_BUFFER, uvVbo);glEnableVertexAttribArray(2);glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), (void*)0);//5.2 加入ebo到当前的vaoglBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);glBindVertexArray(0);
}
void prepareShader() {//1 完成vs与fs的源代码并且装入字符串const char* vertexShaderSource #version 330 core\nlayout (location 0) in vec3 aPos;\nlayout (location 1) in vec3 aColor;\nlayout (location 2) in vec2 aUV;\nout vec3 color;\nout vec2 uv;\nuniform mat4 transform;\nvoid main()\n{\n vec4 position vec4(aPos, 1.0);\n position transform * position;\n gl_Position position;\n color aColor;\n uv aUV;\n}\0;const char* fragmentShaderSource #version 330 core\nout vec4 FragColor;\nin vec3 color;\nin vec2 uv;\nuniform sampler2D sampler;\nvoid main()\n{\n FragColor texture(sampler, uv);\n}\n\0;//2 创建Shader程序vs、fsGLuint vertex, fragment;vertex glCreateShader(GL_VERTEX_SHADER);fragment glCreateShader(GL_FRAGMENT_SHADER);//3 为shader程序输入shader代码glShaderSource(vertex, 1, vertexShaderSource, NULL);glShaderSource(fragment, 1, fragmentShaderSource, NULL);int success 0;char infoLog[1024];//4 执行shader代码编译 glCompileShader(vertex);//检查vertex编译结果glGetShaderiv(vertex, GL_COMPILE_STATUS, success);if (!success) {glGetShaderInfoLog(vertex, 1024, NULL, infoLog);std::cout Error: SHADER COMPILE ERROR --VERTEX \n infoLog std::endl;}glCompileShader(fragment);//检查fragment编译结果glGetShaderiv(fragment, GL_COMPILE_STATUS, success);if (!success) {glGetShaderInfoLog(fragment, 1024, NULL, infoLog);std::cout Error: SHADER COMPILE ERROR --FRAGMENT \n infoLog std::endl;}//5 创建一个Program壳子program glCreateProgram();//6 将vs与fs编译好的结果放到program这个壳子里glAttachShader(program, vertex);glAttachShader(program, fragment);//7 执行program的链接操作形成最终可执行shader程序glLinkProgram(program);//检查链接错误glGetProgramiv(program, GL_LINK_STATUS, success);if (!success) {glGetProgramInfoLog(program, 1024, NULL, infoLog);std::cout Error: SHADER LINK ERROR \n infoLog std::endl;}//清理glDeleteShader(vertex);glDeleteShader(fragment);
}void prepareTextrue()
{//1 stbImage 读取图片int width, height, channels;//--反转y轴stbi_set_flip_vertically_on_load(true);unsigned char* data stbi_load(goku.jpg, width, height, channels, STBI_rgb_alpha);//2 生成纹理并且激活单元绑定glGenTextures(1, texture);//--激活纹理单元--glActiveTexture(GL_TEXTURE0);//--绑定纹理对象--glBindTexture(GL_TEXTURE_2D, texture);//3 传输纹理数据,开辟显存glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);//***释放数据stbi_image_free(data);//4 设置纹理的过滤方式glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);//5 设置纹理的包裹方式glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);//uglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);//v
}void render()
{//执行opengl画布清理操作glClear(GL_COLOR_BUFFER_BIT);//1.绑定当前的programglUseProgram(program);//2 更新Uniform的时候一定要先UserProgram//2.1 通过名称拿到Uniform变量的位置LocationGLint location glGetUniformLocation(program, sampler);//2.2 通过Location更新Uniform变量的值glUniform1f(location, 0);GLint locationTransform glGetUniformLocation(program, transform);//transpose参数表示是否对传输进去的矩阵数据进行转置glUniformMatrix4fv(locationTransform, 1, GL_FALSE, glm::value_ptr(transform));//3 绑定当前的vaoglBindVertexArray(vao);//4 发出绘制指令//glDrawArrays(GL_TRIANGLE_STRIP, 0, 6);glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, 0);
}int main()
{//初始化glfw环境glfwInit();//设置opengl主版本号glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);//设置opengl次版本号glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);//设置opengl启用核心模式glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);//创建窗体对象GLFWwindow* window glfwCreateWindow(800, 600, lenarnOpenGL, nullptr, nullptr);//设置当前窗体对象为opengl的绘制舞台glfwMakeContextCurrent(window);//窗体大小回调glfwSetFramebufferSizeCallback(window, frameBufferSizeCallbakc);//键盘相应回调glfwSetKeyCallback(window, glfwKeyCallback);//使用glad加载所有当前版本opengl的函数if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)){std::cout 初始化glad失败 std::endl;return -1;};//设置opengl视口大小和清理颜色glViewport(0, 0, 800, 600);glClearColor(0.2f, 0.3f, 0.3f, 1.0f);//shaderprepareShader();//vaoprepareVAO();//textureprepareTextrue();//doTransform();//执行窗体循环while (!glfwWindowShouldClose(window)){//接受并分发窗体消息//检查消息队列是否有需要处理的鼠标、键盘等消息//如果有的话就将消息批量处理清空队列glfwPollEvents();doRotation();//渲染操作render();//切换双缓存glfwSwapBuffers(window);}//推出程序前做相关清理glfwTerminate();return 0;
}上述代码分别实现了对图像进行旋转平移缩放的操作。 在VS中定义transform四维矩阵变量将这个变量与位置向量进行相乘即可进行旋转平移缩放。
叠加变换 上面的旋转三角形可以通过叠加来实现
void doTransform()
{旋转三角形float angle 1.0f;transform glm::rotate(transform, glm::radians(angle), glm::vec3(0.0f, 0.0f, 1.0f));
}在每一帧进行渲染时调用此函数即可
