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@ -33,11 +33,34 @@ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#define WIDTH 400 |
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#define HEIGHT 400 |
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#define OFFSET 50 |
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static GLFWwindow* windows[2]; |
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#include "linmath.h" |
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static const char* vertex_shader_text = |
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"uniform mat4 MVP;\n" |
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"attribute vec2 vPos;\n" |
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"varying vec2 texcoord;\n" |
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"void main()\n" |
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"{\n" |
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" gl_Position = MVP * vec4(vPos, 0.0, 1.0);\n" |
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" texcoord = vPos;\n" |
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"}\n"; |
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static const char* fragment_shader_text = |
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"uniform sampler2D texture;\n" |
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"uniform vec3 color;\n" |
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"varying vec2 texcoord;\n" |
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"void main()\n" |
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"{\n" |
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" gl_FragColor = vec4(color * tex2D(texture, texcoord).rgb, 1.0);\n" |
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"}\n"; |
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static const vec2 vertices[4] = |
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{ |
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{ 0.f, 0.f }, |
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{ 1.f, 0.f }, |
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{ 1.f, 1.f }, |
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{ 0.f, 1.f } |
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}; |
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static void error_callback(int error, const char* description) |
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{ |
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@ -50,132 +73,155 @@ static void key_callback(GLFWwindow* window, int key, int scancode, int action, |
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glfwSetWindowShouldClose(window, GLFW_TRUE); |
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} |
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static GLFWwindow* open_window(const char* title, GLFWwindow* share, int posX, int posY) |
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int main(int argc, char** argv) |
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{ |
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GLFWwindow* window; |
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glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE); |
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window = glfwCreateWindow(WIDTH, HEIGHT, title, NULL, share); |
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if (!window) |
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return NULL; |
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glfwMakeContextCurrent(window); |
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gladLoadGLLoader((GLADloadproc) glfwGetProcAddress); |
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glfwSwapInterval(1); |
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glfwSetWindowPos(window, posX, posY); |
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glfwShowWindow(window); |
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GLFWwindow* windows[2]; |
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GLuint texture, vertex_shader, fragment_shader, program, vertex_buffer; |
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GLint mvp_location, vpos_location, color_location, texture_location; |
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glfwSetKeyCallback(window, key_callback); |
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return window; |
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} |
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glfwSetErrorCallback(error_callback); |
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static GLuint create_texture(void) |
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{ |
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int x, y; |
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char pixels[256 * 256]; |
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GLuint texture; |
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if (!glfwInit()) |
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exit(EXIT_FAILURE); |
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glGenTextures(1, &texture); |
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glBindTexture(GL_TEXTURE_2D, texture); |
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glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2); |
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glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0); |
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for (y = 0; y < 256; y++) |
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windows[0] = glfwCreateWindow(400, 400, "First", NULL, NULL); |
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if (!windows[0]) |
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{ |
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for (x = 0; x < 256; x++) |
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pixels[y * 256 + x] = rand() % 256; |
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glfwTerminate(); |
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exit(EXIT_FAILURE); |
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} |
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glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, 256, 256, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, pixels); |
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); |
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); |
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glfwSetKeyCallback(windows[0], key_callback); |
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return texture; |
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} |
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glfwMakeContextCurrent(windows[0]); |
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static void draw_quad(GLuint texture) |
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{ |
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int width, height; |
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glfwGetFramebufferSize(glfwGetCurrentContext(), &width, &height); |
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// Only enable vsync for the first of the windows to be swapped to
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// avoid waiting out the interval for each window
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glfwSwapInterval(1); |
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glViewport(0, 0, width, height); |
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// The contexts are created with the same APIs so the function
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// pointers should be re-usable between them
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gladLoadGLLoader((GLADloadproc) glfwGetProcAddress); |
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// Create the OpenGL objects inside the first context, created above
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// All objects will be shared with the second context, created below
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{ |
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int x, y; |
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char pixels[256 * 256]; |
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GLuint vertex_shader, fragment_shader; |
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glGenTextures(1, &texture); |
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glBindTexture(GL_TEXTURE_2D, texture); |
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for (y = 0; y < 256; y++) |
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{ |
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for (x = 0; x < 256; x++) |
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pixels[y * 256 + x] = rand() % 256; |
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} |
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glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, 256, 256, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, pixels); |
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); |
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); |
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vertex_shader = glCreateShader(GL_VERTEX_SHADER); |
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glShaderSource(vertex_shader, 1, &vertex_shader_text, NULL); |
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glCompileShader(vertex_shader); |
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fragment_shader = glCreateShader(GL_FRAGMENT_SHADER); |
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glShaderSource(fragment_shader, 1, &fragment_shader_text, NULL); |
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glCompileShader(fragment_shader); |
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program = glCreateProgram(); |
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glAttachShader(program, vertex_shader); |
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glAttachShader(program, fragment_shader); |
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glLinkProgram(program); |
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mvp_location = glGetUniformLocation(program, "MVP"); |
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color_location = glGetUniformLocation(program, "color"); |
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texture_location = glGetUniformLocation(program, "texture"); |
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vpos_location = glGetAttribLocation(program, "vPos"); |
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glGenBuffers(1, &vertex_buffer); |
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glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); |
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glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); |
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} |
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glMatrixMode(GL_PROJECTION); |
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glLoadIdentity(); |
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glOrtho(0.f, 1.f, 0.f, 1.f, 0.f, 1.f); |
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glUseProgram(program); |
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glUniform1i(texture_location, 0); |
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glEnable(GL_TEXTURE_2D); |
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glBindTexture(GL_TEXTURE_2D, texture); |
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glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); |
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glBegin(GL_QUADS); |
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glTexCoord2f(0.f, 0.f); |
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glVertex2f(0.f, 0.f); |
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glTexCoord2f(1.f, 0.f); |
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glVertex2f(1.f, 0.f); |
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glTexCoord2f(1.f, 1.f); |
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glVertex2f(1.f, 1.f); |
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glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); |
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glEnableVertexAttribArray(vpos_location); |
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glVertexAttribPointer(vpos_location, 2, GL_FLOAT, GL_FALSE, |
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sizeof(vertices[0]), (void*) 0); |
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glTexCoord2f(0.f, 1.f); |
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glVertex2f(0.f, 1.f); |
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glEnd(); |
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} |
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int main(int argc, char** argv) |
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{ |
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int x, y, width; |
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GLuint texture; |
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glfwSetErrorCallback(error_callback); |
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if (!glfwInit()) |
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exit(EXIT_FAILURE); |
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windows[0] = open_window("First", NULL, OFFSET, OFFSET); |
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if (!windows[0]) |
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windows[1] = glfwCreateWindow(400, 400, "Second", NULL, windows[0]); |
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if (!windows[1]) |
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{ |
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glfwTerminate(); |
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exit(EXIT_FAILURE); |
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} |
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// This is the one and only time we create a texture
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// It is created inside the first context, created above
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// It will then be shared with the second context, created below
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texture = create_texture(); |
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// Place the second window to the right of the first
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{ |
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int xpos, ypos, left, right, width; |
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glfwGetWindowPos(windows[0], &x, &y); |
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glfwGetWindowSize(windows[0], &width, NULL); |
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glfwGetWindowSize(windows[0], &width, NULL); |
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glfwGetWindowFrameSize(windows[0], &left, NULL, &right, NULL); |
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glfwGetWindowPos(windows[0], &xpos, &ypos); |
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// Put the second window to the right of the first one
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windows[1] = open_window("Second", windows[0], x + width + OFFSET, y); |
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if (!windows[1]) |
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{ |
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glfwTerminate(); |
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exit(EXIT_FAILURE); |
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glfwSetWindowPos(windows[1], xpos + width + left + right, ypos); |
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} |
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// Set drawing color for both contexts
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glfwMakeContextCurrent(windows[0]); |
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glColor3f(0.6f, 0.f, 0.6f); |
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glfwSetKeyCallback(windows[1], key_callback); |
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glfwMakeContextCurrent(windows[1]); |
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glColor3f(0.6f, 0.6f, 0.f); |
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glfwMakeContextCurrent(windows[0]); |
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// While objects are shared, the global context state is not and will
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// need to be set up for each context
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glUseProgram(program); |
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glEnable(GL_TEXTURE_2D); |
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glBindTexture(GL_TEXTURE_2D, texture); |
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glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); |
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glEnableVertexAttribArray(vpos_location); |
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glVertexAttribPointer(vpos_location, 2, GL_FLOAT, GL_FALSE, |
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sizeof(vertices[0]), (void*) 0); |
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while (!glfwWindowShouldClose(windows[0]) && |
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!glfwWindowShouldClose(windows[1])) |
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{ |
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glfwMakeContextCurrent(windows[0]); |
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draw_quad(texture); |
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glfwMakeContextCurrent(windows[1]); |
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draw_quad(texture); |
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glfwSwapBuffers(windows[0]); |
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glfwSwapBuffers(windows[1]); |
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int i; |
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const vec3 colors[2] = |
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{ |
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{ 0.6f, 0.6f, 0.f }, |
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{ 0.6f, 0.f, 0.6f } |
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}; |
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for (i = 0; i < 2; i++) |
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{ |
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int width, height; |
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mat4x4 mvp; |
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glfwGetFramebufferSize(windows[i], &width, &height); |
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glfwMakeContextCurrent(windows[i]); |
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glViewport(0, 0, width, height); |
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mat4x4_ortho(mvp, 0.f, 1.f, 0.f, 1.f, 0.f, 1.f); |
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glUniformMatrix4fv(mvp_location, 1, GL_FALSE, (const GLfloat*) mvp); |
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glUniform3fv(color_location, 1, colors[i]); |
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glDrawArrays(GL_TRIANGLE_FAN, 0, 4); |
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glfwSwapBuffers(windows[i]); |
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} |
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glfwWaitEvents(); |
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} |
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