diff options
Diffstat (limited to 'tests/OffscreenContext.cc')
| -rw-r--r-- | tests/OffscreenContext.cc | 43 |
1 files changed, 23 insertions, 20 deletions
diff --git a/tests/OffscreenContext.cc b/tests/OffscreenContext.cc index 01ab9c4..f5eabe0 100644 --- a/tests/OffscreenContext.cc +++ b/tests/OffscreenContext.cc @@ -1,9 +1,11 @@ -/* +/* Create an OpenGL context without creating an OpenGL Window. for Linux. -based on +See Also + glxgears.c by Brian Paul from mesa-demos (mesa3d.org) + http://cgit.freedesktop.org/mesa/demos/tree/src/xdemos?id=mesa-demos-8.0.1 http://www.opengl.org/sdk/docs/man/xhtml/glXIntro.xml http://www.mesa3d.org/brianp/sig97/offscrn.htm http://glprogramming.com/blue/ch07.html @@ -59,20 +61,13 @@ bool create_glx_dummy_window(OffscreenContext &ctx) { /* create a dummy X window without showing it. (without 'mapping' it) - save information to the ctx + and save information to the ctx. - based on http://www.opengl.org/sdk/docs/man/xhtml/glXIntro.xml - which was originally Copyright © 1991-2006 Silicon Graphics, Inc. - licensed under the SGI Free Software B License. - See http://oss.sgi.com/projects/FreeB/. + This purposely does not use glxCreateWindow, to avoid crashes, + "failed to create drawable" errors, and Mesa "WARNING: Application calling + GLX 1.3 function when GLX 1.3 is not supported! This is an application bug!" - also based on glxgears.c by Brian Paul from mesa-demos (mesa3d.org) - - purposely does not use glxCreateWindow, to avoid crashes, - "failed to create drawable" errors, and Mesa "This is an application bug!" - warnings about GLX 1.3. - - this function will alter ctx.openGLContext and ctx.xwindow if successfull + This function will alter ctx.openGLContext and ctx.xwindow if successfull */ int attributes[] = { @@ -86,8 +81,8 @@ bool create_glx_dummy_window(OffscreenContext &ctx) Display *dpy = ctx.xdisplay; - int numReturned = 0; - GLXFBConfig *fbconfigs = glXChooseFBConfig( dpy, DefaultScreen(dpy), attributes, &numReturned ); + int num_returned = 0; + GLXFBConfig *fbconfigs = glXChooseFBConfig( dpy, DefaultScreen(dpy), attributes, &num_returned ); if ( fbconfigs == NULL ) { cerr << "glXChooseFBConfig failed\n"; return false; @@ -100,9 +95,9 @@ bool create_glx_dummy_window(OffscreenContext &ctx) return false; } + // can't depend on xWin==NULL at failure. use a custom Xlib error handler instead. original_xlib_handler = XSetErrorHandler( XCreateWindow_error ); Window xWin = XCreateSimpleWindow( dpy, DefaultRootWindow(dpy), 0,0,10,10, 0,0,0 ); - // can't depend on xWin==NULL at failure. catch Xlib Errors instead. XSync( dpy, false ); if ( XCreateWindow_failed ) { XFree( visinfo ); @@ -110,7 +105,8 @@ bool create_glx_dummy_window(OffscreenContext &ctx) return false; } XSetErrorHandler( original_xlib_handler ); - // do not call XMapWindow - keep the window hidden + + // Most programs would call XMapWindow here. But we don't, to keep the window hidden GLXContext context = glXCreateNewContext( dpy, fbconfigs[0], GLX_RGBA_TYPE, NULL, True ); if ( context == NULL ) { @@ -153,13 +149,15 @@ Bool create_glx_dummy_context(OffscreenContext &ctx) return False; } + // glxQueryVersion is not always reliable. Use it, but then + // also check to see if GLX 1.3 functions exist + glXQueryVersion(ctx.xdisplay, &major, &minor); if ( major==1 && minor<=2 && glXGetVisualFromFBConfig==NULL ) { cerr << "Error: GLX version 1.3 functions missing. " << "Your GLX version: " << major << "." << minor << endl; } else { - // if glXGetVisualFromFBConfig exists, pretend we have >=1.3 result = create_glx_dummy_window(ctx); } @@ -198,7 +196,12 @@ OffscreenContext *create_offscreen_context(int w, int h) return NULL; } - glewInit(); //must come after Context creation and before FBO calls. + // glewInit must come after Context creation and before FBO calls. + glewInit(); + if (GLEW_OK != err) { + fprintf(stderr, "Unable to init GLEW: %s\n", glewGetErrorString(err)); + exit(1); + } glewCheck(); ctx->fbo = fbo_new(); |