https:\/\/www.opengl.org\/sdk\/docs\/man2\/xhtml\/glXIntro.xml<\/a><\/p>\nBelow is a minimal example of creating an RGBA-format X window that’s compatible with OpenGL using GLX 1.3 commands. The window is cleared to yellow when the program runs. The program does minimal error checking; all return values should be checked.<\/p>\n
#include < stdio.h >\r\n#include < stdlib.h >\r\n#include < GL\/gl.h >\r\n#include < GL\/glx.h >\r\n\r\nint singleBufferAttributess[] = {\r\n GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,\r\n GLX_RENDER_TYPE, GLX_RGBA_BIT,\r\n GLX_RED_SIZE, 1, \/* Request a single buffered color buffer *\/\r\n GLX_GREEN_SIZE, 1, \/* with the maximum number of color bits *\/\r\n GLX_BLUE_SIZE, 1, \/* for each component *\/\r\n None\r\n};\r\n\r\nint doubleBufferAttributes[] = {\r\n GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,\r\n GLX_RENDER_TYPE, GLX_RGBA_BIT,\r\n GLX_DOUBLEBUFFER, True, \/* Request a double-buffered color buffer with *\/\r\n GLX_RED_SIZE, 1, \/* the maximum number of bits per component *\/\r\n GLX_GREEN_SIZE, 1, \r\n GLX_BLUE_SIZE, 1,\r\n None\r\n};\r\n\r\n\r\nstatic Bool WaitForNotify( Display *dpy, XEvent *event, XPointer arg ) {\r\n return (event->type == MapNotify) && (event->xmap.window == (Window) arg);\r\n}\r\nint main( int argc, char *argv[] )\r\n{\r\n Display *dpy;\r\n Window xWin;\r\n XEvent event;\r\n XVisualInfo *vInfo;\r\n XSetWindowAttributes swa;\r\n GLXFBConfig *fbConfigs;\r\n GLXContext context;\r\n GLXWindow glxWin;\r\n int swaMask;\r\n int numReturned;\r\n int swapFlag = True;\r\n\r\n \/* Open a connection to the X server *\/\r\n dpy = XOpenDisplay( NULL );\r\n if ( dpy == NULL ) {\r\n printf( \"Unable to open a connection to the X servern\" );\r\n exit( EXIT_FAILURE );\r\n }\r\n\r\n \/* Request a suitable framebuffer configuration - try for a double \r\n ** buffered configuration first *\/\r\n fbConfigs = glXChooseFBConfig( dpy, DefaultScreen(dpy),\r\n doubleBufferAttributes, &numReturned );\r\n\r\n if ( fbConfigs == NULL ) { \/* no double buffered configs available *\/\r\n fbConfigs = glXChooseFBConfig( dpy, DefaultScreen(dpy),\r\n singleBufferAttributess, &numReturned );\r\n swapFlag = False;\r\n }\r\n\r\n \/* Create an X colormap and window with a visual matching the first\r\n ** returned framebuffer config *\/\r\n vInfo = glXGetVisualFromFBConfig( dpy, fbConfigs[0] );\r\n\r\n swa.border_pixel = 0;\r\n swa.event_mask = StructureNotifyMask;\r\n swa.colormap = XCreateColormap( dpy, RootWindow(dpy, vInfo->screen),\r\n vInfo->visual, AllocNone );\r\n\r\n swaMask = CWBorderPixel | CWColormap | CWEventMask;\r\n\r\n xWin = XCreateWindow( dpy, RootWindow(dpy, vInfo->screen), 0, 0, 256, 256,\r\n 0, vInfo->depth, InputOutput, vInfo->visual,\r\n swaMask, &swa );\r\n\r\n \/* Create a GLX context for OpenGL rendering *\/\r\n context = glXCreateNewContext( dpy, fbConfigs[0], GLX_RGBA_TYPE,\r\n\t\t\t\t NULL, True );\r\n\r\n \/* Create a GLX window to associate the frame buffer configuration\r\n ** with the created X window *\/\r\n glxWin = glXCreateWindow( dpy, fbConfigs[0], xWin, NULL );\r\n \r\n \/* Map the window to the screen, and wait for it to appear *\/\r\n XMapWindow( dpy, xWin );\r\n XIfEvent( dpy, &event, WaitForNotify, (XPointer) xWin );\r\n\r\n \/* Bind the GLX context to the Window *\/\r\n glXMakeContextCurrent( dpy, glxWin, glxWin, context );\r\n\r\n \/* OpenGL rendering ... *\/\r\n glClearColor( 1.0, 1.0, 0.0, 1.0 );\r\n glClear( GL_COLOR_BUFFER_BIT );\r\n\r\n glFlush();\r\n \r\n if ( swapFlag )\r\n glXSwapBuffers( dpy, glxWin );\r\n\r\n sleep( 10 );\r\n exit( EXIT_SUCCESS );\r\n}<\/pre>\n <\/p>\n","protected":false},"excerpt":{"rendered":"
Writing the OpenGL context creation plumbing on Linux isn’t 100% intuitive. It’s always good to have a handy getting started guide. With developers increasingly using engines such as Unity, the number of people writing directly to OpenGL is shrinking – and so are some of the online resources to get over this initial step. I decided to collect a few links and copy critical\u00a0sample code here for when I need to whip something up quickly. Some links to good…<\/p>\n
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