1 //
2 // Created by sry on 2021/7/6.
3 //
4 #include <glad/glad.h>
5 #include <GLFW/glfw3.h>
6 #include<iostream>
7 #include<cmath>
8 using namespace std;
9
10 void framebuffer_size_callback(GLFWwindow* window, int width, int height)
11 {
12 glViewport(0, 0, width, height); // opengl_frame glfw_frame new_frame，知道为啥有这么多JB帧了吧
13 }
14 /*
15 *
16 * 这里我们检查用户是否按下了返回键(Esc)（如果没有按下，glfwGetKey将会返回GLFW_RELEASE。
17 * 如果用户的确按下了返回键，我们将通过glfwSetwindowShouldClose使用把WindowShouldClose属性设置为 true的方法关闭GLFW。
18 *
19 * */
20 void processInput(GLFWwindow *window)
21 {
22 if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
23 glfwSetWindowShouldClose(window, true);
24 }
25
26 // glsl 渲染语言，这和C++调用Matlab差不多
27 const char *vertexShaderSource = "#version 330 core\n"
28 "layout (location = 0) in vec3 aPos;\n"
29 "void main()\n"
30 "{\n"
31 " gl_Position = vec4(aPos, 1.0);\n"
32 "}\0";
33
34 const char *fragmentShaderSource = "#version 330 core\n"
35 "out vec4 FragColor;\n"
36 "uniform vec4 ourColor;\n"
37 "void main()\n"
38 "{\n"
39 " FragColor = ourColor;\n"
40 "}\n\0";
41
42 int main()
43 {
44 // <1>、初始化GLFW
45 glfwInit();
46 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); // opengl3.3
47 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
48 glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 只用核心通用模块
49
50 // <2>、glfw窗口创建
51 GLFWwindow* window = glfwCreateWindow(800, 600, "shiruiyu", NULL, NULL);
52 if (window == NULL)
53 {
54 cout << "fuck" << endl;
55 glfwTerminate(); // Release
56 return -1;
57 }
58 glfwMakeContextCurrent(window); // 通知GLFW将我们窗口的上下文设置为当前线程的主上下文了。
59 /*
60 * 告诉OpenGL渲染窗口的尺寸大小
61 * OpenGL坐标范围只为-1到1，因此我们事实上将(-1到1)范围内的坐标映射到(0, 800)和(0, 600)。
62 * */
63 // 对窗口注册一个回调函数(Callback Function)，它会在每次窗口大小被调整的时候被调用
64 glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
65 /*
66 * <3>、利用glad加载所有OpenGL函数地址
67 * GLAD是用来管理OpenGL的函数指针的，所以在调用任何OpenGL的函数之前我们需要初始化GLAD
68 * */
69 if (!gladLoadGLLoader((GLADloadproc) glfwGetProcAddress))
70 {
71 cout << "Failed to init GLAD" << endl;
72 return -1;
73 }
74 // <4>、构建、编译shader program
75 // 创建顶点渲染器，vertex shader
76 unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
77 glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
78 glCompileShader(vertexShader);
79 // 验证渲染器是否正常
80 int success = 0;
81 char infoLog[512];
82 glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
83 if (!success)
84 {
85 glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
86 std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
87 }
88 // 创建线段渲染器，fragment shader
89 unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
90 glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
91 glCompileShader(fragmentShader);
92 // 验证渲染器是否正常
93 success = 0;
94 glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
95 if (!success)
96 {
97 glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
98 std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
99 }
100 // 链接渲染器，link shaders
101 unsigned int shaderProgram = glCreateProgram();
102 glAttachShader(shaderProgram, vertexShader);
103 glAttachShader(shaderProgram, fragmentShader);
104 glLinkProgram(shaderProgram);
105 // 检测链接错误
106 success = 0;
107 glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
108 if (!success)
109 {
110 glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
111 std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
112 }
113 glDeleteShader(vertexShader);
114 glDeleteShader(fragmentShader);
115
116 // set up vertex data (and buffer(s)) and configure vertex attributes
117 // ------------------------------------------------------------------
118 float vertices[] = {
119 -0.5f, -0.5f, 0.0f, // left
120 0.5f, -0.5f, 0.0f, // right
121 0.0f, 0.5f, 0.0f // top
122 };
123 unsigned int VBO, VAO; // ???
124 glGenVertexArrays(1, &VAO);
125 glGenBuffers(1, &VBO);
126 // bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).
127 glBindVertexArray(VAO);
128
129 glBindBuffer(GL_ARRAY_BUFFER, VBO);
130 glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
131
132 glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
133 glEnableVertexAttribArray(0);
134
135 // note that this is allowed, the call to glVertexAttribPointer registered VBO as the vertex attribute's bound vertex buffer object so afterwards we can safely unbind
136 glBindBuffer(GL_ARRAY_BUFFER, 0);
137 // You can unbind the VAO afterwards so other VAO calls won't accidentally modify this VAO, but this rarely happens. Modifying other
138 // VAOs requires a call to glBindVertexArray anyways so we generally don't unbind VAOs (nor VBOs) when it's not directly necessary.
139 glBindVertexArray(0);
140
141 // 循环渲染
142 while(!glfwWindowShouldClose(window)) // 检查一次GLFW是否被要求退出
143 {
144 // 输入
145 processInput(window);
146
147 // 渲染指令
148 // 清除颜色缓冲
149 glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
150 glClear(GL_COLOR_BUFFER_BIT);
151 // 激活着色器
152 glUseProgram(shaderProgram);
153
154 // 更新uniform颜色
155 float timeValue = glfwGetTime();
156 float greenValue = std::sin(timeValue)/2.0f + 0.5f;
157 int vertexColorLocation = glGetUniformLocation(shaderProgram, "ourColor");
158 glUniform4f(vertexColorLocation, 0.0f, greenValue, 0.0f, 1.0f);
159
160
161 // 画第一个三角形
162
163 glBindVertexArray(VAO);
164 glDrawArrays(GL_TRIANGLES, 0, 3);// Primitive:GL_POINTS、GL_TRIANGLES、GL_LINE_STRIP
165
166
167
168
169
170 // 检查并调用事件，交换缓冲
171 glfwPollEvents(); // 检查有没有触发什么事件（比如键盘输入、鼠标移动等）、更新窗口状态，并调用对应的回调函数（可以通过回调方法手动设置）。
172 glfwSwapBuffers(window); // 函数会交换颜色缓冲（它是一个储存着GLFW窗口每一个像素颜色值的大缓冲），它在这一迭代中被用来绘制，并且将会作为输出显示在屏幕上。
173
174 }
175
176 glDeleteVertexArrays(1, &VAO);
177 glDeleteBuffers(1, &VBO);
178 glDeleteProgram(shaderProgram);
179
180 // release
181 glfwTerminate();
182
183 return 0;
184 }
标签：include,openGL,int,学习,vertexShader,window,GLFW,NULL,着色器 From： https://www.cnblogs.com/feiyull/p/14977039.html