Atlas - sharing.c
Home / ext / glfw / examples Lines: 19 | Size: 7146 bytes [Download] [Show on GitHub] [Search similar files] [Raw] [Raw (proxy)][FILE BEGIN]1//======================================================================== 2// Context sharing example 3// Copyright (c) Camilla Löwy <[email protected]> 4// 5// This software is provided 'as-is', without any express or implied 6// warranty. In no event will the authors be held liable for any damages 7// arising from the use of this software. 8// 9// Permission is granted to anyone to use this software for any purpose, 10// including commercial applications, and to alter it and redistribute it 11// freely, subject to the following restrictions: 12// 13// 1. The origin of this software must not be misrepresented; you must not 14// claim that you wrote the original software. If you use this software 15// in a product, an acknowledgment in the product documentation would 16// be appreciated but is not required. 17// 18// 2. Altered source versions must be plainly marked as such, and must not 19// be misrepresented as being the original software. 20// 21// 3. This notice may not be removed or altered from any source 22// distribution. 23// 24//======================================================================== 25 26#define GLAD_GL_IMPLEMENTATION 27#include <glad/gl.h> 28#define GLFW_INCLUDE_NONE 29#include <GLFW/glfw3.h> 30 31#include <stdio.h> 32#include <stdlib.h> 33 34#include "linmath.h" 35 36static const char* vertex_shader_text = 37"#version 110\n" 38"uniform mat4 MVP;\n" 39"attribute vec2 vPos;\n" 40"varying vec2 texcoord;\n" 41"void main()\n" 42"{\n" 43" gl_Position = MVP * vec4(vPos, 0.0, 1.0);\n" 44" texcoord = vPos;\n" 45"}\n"; 46 47static const char* fragment_shader_text = 48"#version 110\n" 49"uniform sampler2D texture;\n" 50"uniform vec3 color;\n" 51"varying vec2 texcoord;\n" 52"void main()\n" 53"{\n" 54" gl_FragColor = vec4(color * texture2D(texture, texcoord).rgb, 1.0);\n" 55"}\n"; 56 57static const vec2 vertices[4] = 58{ 59 { 0.f, 0.f }, 60 { 1.f, 0.f }, 61 { 1.f, 1.f }, 62 { 0.f, 1.f } 63}; 64 65static void error_callback(int error, const char* description) 66{ 67 fprintf(stderr, "Error: %s\n", description); 68} 69 70static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods) 71{ 72 if (action == GLFW_PRESS && key == GLFW_KEY_ESCAPE) 73 glfwSetWindowShouldClose(window, GLFW_TRUE); 74} 75 76int main(int argc, char** argv) 77{ 78 GLFWwindow* windows[2]; 79 GLuint texture, program, vertex_buffer; 80 GLint mvp_location, vpos_location, color_location, texture_location; 81 82 glfwSetErrorCallback(error_callback); 83 84 if (!glfwInit()) 85 exit(EXIT_FAILURE); 86 87 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2); 88 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0); 89 90 windows[0] = glfwCreateWindow(400, 400, "First", NULL, NULL); 91 if (!windows[0]) 92 { 93 glfwTerminate(); 94 exit(EXIT_FAILURE); 95 } 96 97 glfwSetKeyCallback(windows[0], key_callback); 98 99 glfwMakeContextCurrent(windows[0]); 100 101 // Only enable vsync for the first of the windows to be swapped to 102 // avoid waiting out the interval for each window 103 glfwSwapInterval(1); 104 105 // The contexts are created with the same APIs so the function 106 // pointers should be re-usable between them 107 gladLoadGL(glfwGetProcAddress); 108 109 // Create the OpenGL objects inside the first context, created above 110 // All objects will be shared with the second context, created below 111 { 112 int x, y; 113 char pixels[16 * 16]; 114 GLuint vertex_shader, fragment_shader; 115 116 glGenTextures(1, &texture); 117 glBindTexture(GL_TEXTURE_2D, texture); 118 119 srand((unsigned int) glfwGetTimerValue()); 120 121 for (y = 0; y < 16; y++) 122 { 123 for (x = 0; x < 16; x++) 124 pixels[y * 16 + x] = rand() % 256; 125 } 126 127 glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, 16, 16, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, pixels); 128 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); 129 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); 130 131 vertex_shader = glCreateShader(GL_VERTEX_SHADER); 132 glShaderSource(vertex_shader, 1, &vertex_shader_text, NULL); 133 glCompileShader(vertex_shader); 134 135 fragment_shader = glCreateShader(GL_FRAGMENT_SHADER); 136 glShaderSource(fragment_shader, 1, &fragment_shader_text, NULL); 137 glCompileShader(fragment_shader); 138 139 program = glCreateProgram(); 140 glAttachShader(program, vertex_shader); 141 glAttachShader(program, fragment_shader); 142 glLinkProgram(program); 143 144 mvp_location = glGetUniformLocation(program, "MVP"); 145 color_location = glGetUniformLocation(program, "color"); 146 texture_location = glGetUniformLocation(program, "texture"); 147 vpos_location = glGetAttribLocation(program, "vPos"); 148 149 glGenBuffers(1, &vertex_buffer); 150 glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); 151 glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); 152 } 153 154 glUseProgram(program); 155 glUniform1i(texture_location, 0); 156 157 glEnable(GL_TEXTURE_2D); 158 glBindTexture(GL_TEXTURE_2D, texture); 159 160 glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); 161 glEnableVertexAttribArray(vpos_location); 162 glVertexAttribPointer(vpos_location, 2, GL_FLOAT, GL_FALSE, 163 sizeof(vertices[0]), (void*) 0); 164 165 windows[1] = glfwCreateWindow(400, 400, "Second", NULL, windows[0]); 166 if (!windows[1]) 167 { 168 glfwTerminate(); 169 exit(EXIT_FAILURE); 170 } 171 172 // Place the second window to the right of the first 173 { 174 int xpos, ypos, left, right, width; 175 176 glfwGetWindowSize(windows[0], &width, NULL); 177 glfwGetWindowFrameSize(windows[0], &left, NULL, &right, NULL); 178 glfwGetWindowPos(windows[0], &xpos, &ypos); 179 180 glfwSetWindowPos(windows[1], xpos + width + left + right, ypos); 181 } 182 183 glfwSetKeyCallback(windows[1], key_callback); 184 185 glfwMakeContextCurrent(windows[1]); 186 187 // While objects are shared, the global context state is not and will 188 // need to be set up for each context 189 190 glUseProgram(program); 191 192 glEnable(GL_TEXTURE_2D); 193 glBindTexture(GL_TEXTURE_2D, texture); 194 195 glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); 196 glEnableVertexAttribArray(vpos_location); 197 glVertexAttribPointer(vpos_location, 2, GL_FLOAT, GL_FALSE, 198 sizeof(vertices[0]), (void*) 0); 199 200 while (!glfwWindowShouldClose(windows[0]) && 201 !glfwWindowShouldClose(windows[1])) 202 { 203 int i; 204 const vec3 colors[2] = 205 { 206 { 0.8f, 0.4f, 1.f }, 207 { 0.3f, 0.4f, 1.f } 208 }; 209 210 for (i = 0; i < 2; i++) 211 { 212 int width, height; 213 mat4x4 mvp; 214 215 glfwGetFramebufferSize(windows[i], &width, &height); 216 glfwMakeContextCurrent(windows[i]); 217 218 glViewport(0, 0, width, height); 219 220 mat4x4_ortho(mvp, 0.f, 1.f, 0.f, 1.f, 0.f, 1.f); 221 glUniformMatrix4fv(mvp_location, 1, GL_FALSE, (const GLfloat*) mvp); 222 glUniform3fv(color_location, 1, colors[i]); 223 glDrawArrays(GL_TRIANGLE_FAN, 0, 4); 224 225 glfwSwapBuffers(windows[i]); 226 } 227 228 glfwWaitEvents(); 229 } 230 231 glfwTerminate(); 232 exit(EXIT_SUCCESS); 233} 234 235[FILE END](C) 2025 0x4248 (C) 2025 4248 Media and 4248 Systems, All part of 0x4248 See LICENCE files for more information. 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