OpenGL太可怕了。。。必需得把学的记下来，不然绝壁忘。
首先贴出代码，然后分析创建一个OpenGL程序都需要什么
1 #include <cstdio>
2 #include <cstdlib>
3
4 #include <GL/glew.h>
5
6 #include <GLFW/glfw3.h>
7
8 #include <glm/glm.hpp>
9 #include <glm/gtc/matrix_transform.hpp>
10 using namespace glm;
11 using namespace std;
12
13 #include <shader.hpp>
14 #include <shader.cpp>
15
16 static const GLfloat g_vertex_buffer_data[] = {
17 -1.0f,-1.0f,-1.0f, // triangle 1 : begin
18 -1.0f,-1.0f, 1.0f,
19 -1.0f, 1.0f, 1.0f, // triangle 1 : end
20 1.0f, 1.0f,-1.0f, // triangle 2 : begin
21 -1.0f,-1.0f,-1.0f,
22 -1.0f, 1.0f,-1.0f, // triangle 2 : end
23 1.0f,-1.0f, 1.0f,
24 -1.0f,-1.0f,-1.0f,
25 1.0f,-1.0f,-1.0f,
26 1.0f, 1.0f,-1.0f,
27 1.0f,-1.0f,-1.0f,
28 -1.0f,-1.0f,-1.0f,
29 -1.0f,-1.0f,-1.0f,
30 -1.0f, 1.0f, 1.0f,
31 -1.0f, 1.0f,-1.0f,
32 1.0f,-1.0f, 1.0f,
33 -1.0f,-1.0f, 1.0f,
34 -1.0f,-1.0f,-1.0f,
35 -1.0f, 1.0f, 1.0f,
36 -1.0f,-1.0f, 1.0f,
37 1.0f,-1.0f, 1.0f,
38 1.0f, 1.0f, 1.0f,
39 1.0f,-1.0f,-1.0f,
40 1.0f, 1.0f,-1.0f,
41 1.0f,-1.0f,-1.0f,
42 1.0f, 1.0f, 1.0f,
43 1.0f,-1.0f, 1.0f,
44 1.0f, 1.0f, 1.0f,
45 1.0f, 1.0f,-1.0f,
46 -1.0f, 1.0f,-1.0f,
47 1.0f, 1.0f, 1.0f,
48 -1.0f, 1.0f,-1.0f,
49 -1.0f, 1.0f, 1.0f,
50 1.0f, 1.0f, 1.0f,
51 -1.0f, 1.0f, 1.0f,
52 1.0f,-1.0f, 1.0f
53 };
54
55 //每个顶点一个颜色
56 static const GLfloat g_color_buffer_data[] = {
57 0.583f, 0.771f, 0.014f,
58 0.609f, 0.115f, 0.436f,
59 0.327f, 0.483f, 0.844f,
60 0.822f, 0.569f, 0.201f,
61 0.435f, 0.602f, 0.223f,
62 0.310f, 0.747f, 0.185f,
63 0.597f, 0.770f, 0.761f,
64 0.559f, 0.436f, 0.730f,
65 0.359f, 0.583f, 0.152f,
66 0.483f, 0.596f, 0.789f,
67 0.559f, 0.861f, 0.639f,
68 0.195f, 0.548f, 0.859f,
69 0.014f, 0.184f, 0.576f,
70 0.771f, 0.328f, 0.970f,
71 0.406f, 0.615f, 0.116f,
72 0.676f, 0.977f, 0.133f,
73 0.971f, 0.572f, 0.833f,
74 0.140f, 0.616f, 0.489f,
75 0.997f, 0.513f, 0.064f,
76 0.945f, 0.719f, 0.592f,
77 0.543f, 0.021f, 0.978f,
78 0.279f, 0.317f, 0.505f,
79 0.167f, 0.620f, 0.077f,
80 0.347f, 0.857f, 0.137f,
81 0.055f, 0.953f, 0.042f,
82 0.714f, 0.505f, 0.345f,
83 0.783f, 0.290f, 0.734f,
84 0.722f, 0.645f, 0.174f,
85 0.302f, 0.455f, 0.848f,
86 0.225f, 0.587f, 0.040f,
87 0.517f, 0.713f, 0.338f,
88 0.053f, 0.959f, 0.120f,
89 0.393f, 0.621f, 0.362f,
90 0.673f, 0.211f, 0.457f,
91 0.820f, 0.883f, 0.371f,
92 0.982f, 0.099f, 0.879f
93 };
94
95 int main() {
96 if(!glfwInit()) {
97 fprintf(stderr, "Failed To init OpenGL\n");
98 }
99
100 // We want OpenGL 3.3
101 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
102 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
103 // To make MacOS happy; should not be needed
104 glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
105 glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); //We don‘t want the old OpenGL
106
107 // Open a window and create its OpenGL context
108 // (In the accompanying source code, this variable is global)
109 GLFWwindow* window;
110 window = glfwCreateWindow(800, 600, "Tutorial 01", NULL, NULL);
111 if( window == NULL ){
112 fprintf( stderr, "Failed to open GLFW window. If you have an Intel GPU, they are not 3.3 compatible. Try the 2.1 version of the tutorials.\n" );
113 glfwTerminate();
114 return -1;
115 }
116 glfwMakeContextCurrent(window); // Initialize GLEW
117 glewExperimental = true; // Needed in core profile
118
119 //z-buffer
120 glEnable(GL_DEPTH_TEST);
121 glDepthFunc(GL_LEFT);
122
123 if (glewInit() != GLEW_OK) {
124 fprintf(stderr, "Failed to initialize GLEW\n");
125 return -1;
126 }
127
128 //背景颜色
129 glClearColor(0.0f, 0.0f, 0.4f, 0.0f);
130
131 //shader
132 GLuint programID = LoadShaders( "/Users/jeff/IDEProjects/xcode_projects/openGL/openGL/vertex.shader", "/Users/jeff/IDEProjects/xcode_projects/openGL/openGL/fragment.shader" );
133
134 GLuint VertexArrayID;
135 glGenVertexArrays(1, &VertexArrayID);
136 glBindVertexArray(VertexArrayID);
137
138 //vertex buffer
139 GLuint vertexbuffer;
140 glGenBuffers(1, &vertexbuffer);
141 glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
142 glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);
143
144 //color buffer
145 GLuint colorbuffer;
146 glGenBuffers(1, &colorbuffer);
147 glBindBuffer(GL_ARRAY_BUFFER, colorbuffer);
148 glBufferData(GL_ARRAY_BUFFER, sizeof(g_color_buffer_data), g_color_buffer_data, GL_STATIC_DRAW);
149
150 mat4 Projection = perspective(radians(70.0f), (float)4/3, 0.1f, 1000.f);
151
152 mat4 View = lookAt(vec3(3, 4, -5), vec3(0,0,0), vec3(0,1,0));
153
154 mat4 Model = mat4(1.0f);
155
156 //模型到投影转换
157 mat4 mvp = Projection * View * Model;
158
159 GLuint MatrixID = glGetUniformLocation(programID, "mvp");
160
161 while(glfwGetKey(window, GLFW_KEY_ESCAPE) != GLFW_PRESS && !glfwWindowShouldClose(window)) {
162 //每次开始时清空画布
163 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
164
165 //使用shader
166 glUseProgram(programID);
167
168 //把变换矩阵送进shader
169 glUniformMatrix4fv(MatrixID, 1, GL_FALSE, &mvp[0][0]);
170
171 //画三角形
172 glEnableVertexAttribArray(0);
173 glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
174 glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (void*)0);
175
176 //三角形颜色
177 glEnableVertexAttribArray(1);
178 glBindBuffer(GL_ARRAY_BUFFER, colorbuffer);
179 glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, (void*)0);
180
181 //draw call
182 glDrawArrays(GL_TRIANGLES, 0, 12 * 3);
183
184 glDisableVertexAttribArray(0);
185 glDisableVertexAttribArray(1);
186
187 glfwSwapBuffers(window);
188 glfwPollEvents();
189 }
190 glfwTerminate();
191 return 0;
192 }
Code
时间： 2024-10-11 10:56:59