GLFW简介

2024-07-16 14:16| 来源: 网络整理| 查看: 265

文章目录 BuildGetting startedExamples GLFW 是配合 OpenGL 使用的轻量级工具程序库，缩写自 Graphics Library Framework（图形库框架）。GLFW 的主要功能是创建并管理窗口和 OpenGL 上下文，同时还提供了处理手柄、键盘、鼠标输入的功能。有类似功能的库还有 GLUT和 SDL。

Build 下载 $ git clone https://github.com/glfw/glfw.git 编译 && 安装 $ cd glfw && mkdir build && cd build && cmake .. && make -j8 && make install Getting started

可以阅读Getting started来理解GLFW3的使用，通过一个例子讲解如何使用GLFW3来创建一个窗口和绘制一个旋转的三角形，当关闭窗口时如何释放资源。

#include // 需要依赖glad这个库 #define GLFW_INCLUDE_NONE #include #include "linmath.h" // 这个是glfw3里面的一个文件，可以从里面拿到，不过编译安装的时候不会安装到系统目录 #include #include static const struct { float x, y; float r, g, b; } vertices[3] = { { -0.6f, -0.4f, 1.f, 0.f, 0.f }, { 0.6f, -0.4f, 0.f, 1.f, 0.f }, { 0.f, 0.6f, 0.f, 0.f, 1.f } }; // 一个GLES Vertex Shader static const char* vertex_shader_text = "#version 110\n" "uniform mat4 MVP;\n" "attribute vec3 vCol;\n" "attribute vec2 vPos;\n" "varying vec3 color;\n" "void main()\n" "{\n" " gl_Position = MVP * vec4(vPos, 0.0, 1.0);\n" " color = vCol;\n" "}\n"; // 一个GLES Fragment Shader static const char* fragment_shader_text = "#version 110\n" "varying vec3 color;\n" "void main()\n" "{\n" " gl_FragColor = vec4(color, 1.0);\n" "}\n"; static void error_callback(int error, const char* description) { fprintf(stderr, "Error: %s\n", description); } static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods) { if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS) glfwSetWindowShouldClose(window, GLFW_TRUE); } int main(void) { GLFWwindow* window; GLuint vertex_buffer, vertex_shader, fragment_shader, program; GLint mvp_location, vpos_location, vcol_location; // 设置错误回调 glfwSetErrorCallback(error_callback); if (!glfwInit()) exit(EXIT_FAILURE); // 设置使用2.0版本的GL glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0); // 创建一个窗口，窗口名字为"Simple example" window = glfwCreateWindow(640, 480, "Simple example", NULL, NULL); if (!window) { glfwTerminate(); exit(EXIT_FAILURE); } // 设置按键回调 glfwSetKeyCallback(window, key_callback); // 绑定当前线程的Content为window glfwMakeContextCurrent(window); // glfwGetProcAddress是对gl库dlsym的封装，gladLoadGLLoader会去尝试加载所有版本的gl库 gladLoadGLLoader((GLADloadproc)glfwGetProcAddress); // 设置swap间隔 glfwSwapInterval(1); // 创建顶点buffer，并上传顶点 glGenBuffers(1, &vertex_buffer); glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); // 创建，加载，编译Fragment Shader vertex_shader = glCreateShader(GL_VERTEX_SHADER); glShaderSource(vertex_shader, 1, &vertex_shader_text, NULL); glCompileShader(vertex_shader); // 创建，加载，编译Vertex Shader fragment_shader = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(fragment_shader, 1, &fragment_shader_text, NULL); glCompileShader(fragment_shader); // 创建，链接Program program = glCreateProgram(); glAttachShader(program, vertex_shader); glAttachShader(program, fragment_shader); glLinkProgram(program); // 获取shader中顶点对应的location mvp_location = glGetUniformLocation(program, "MVP"); vpos_location = glGetAttribLocation(program, "vPos"); vcol_location = glGetAttribLocation(program, "vCol"); // 设置顶点的值 glEnableVertexAttribArray(vpos_location); glVertexAttribPointer(vpos_location, 2, GL_FLOAT, GL_FALSE, sizeof(vertices[0]), (void*) 0); glEnableVertexAttribArray(vcol_location); glVertexAttribPointer(vcol_location, 3, GL_FLOAT, GL_FALSE, sizeof(vertices[0]), (void*) (sizeof(float) * 2)); // 实时获取窗口的大小，根据时间实时旋转三角形 while (!glfwWindowShouldClose(window)) { float ratio; int width, height; mat4x4 m, p, mvp; glfwGetFramebufferSize(window, &width, &height); ratio = width / (float) height; glViewport(0, 0, width, height); glClear(GL_COLOR_BUFFER_BIT); mat4x4_identity(m); mat4x4_rotate_Z(m, m, (float) glfwGetTime()); mat4x4_ortho(p, -ratio, ratio, -1.f, 1.f, 1.f, -1.f); mat4x4_mul(mvp, p, m); glUseProgram(program); glUniformMatrix4fv(mvp_location, 1, GL_FALSE, (const GLfloat*) mvp); glDrawArrays(GL_TRIANGLES, 0, 3); glfwSwapBuffers(window); glfwPollEvents(); } // 销毁资源 glfwDestroyWindow(window); glfwTerminate(); exit(EXIT_SUCCESS); } Examples

glfw/examples目录下有13个例子可以参考

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