From ece8d2bb056aad9f6937509abae636effb053fc0 Mon Sep 17 00:00:00 2001 From: "Ryan C. Gordon" Date: Mon, 2 Feb 2015 01:05:41 -0500 Subject: [PATCH] X11: Fixes for OpenGL 3.0 and later context creation. - Don't create a temporary context first; this was probably due to Windows needing one to get the address of wglCreateContextAttribsARB(), but that's a unique quirk of WGL, and doesn't apply to glX. The glX spec explicitly says you have to get a function pointer that works with any context from glXGetProcAddress(), including when no context exists. - Properly check for the GLX_ARB_create_context instead of just looking for a non-NULL glXCreateContextAttribsARB()...some implementations, like Mesa, never return NULL for function lookups (Mesa returns pointers into a jump table that is filled out when the GL is initialized; since you can look up functions before you have a valid context, it can't definitely say a function isn't valid at that point). --- src/video/x11/SDL_x11opengl.c | 117 +++++++++++++++------------------- src/video/x11/SDL_x11opengl.h | 2 + 2 files changed, 52 insertions(+), 67 deletions(-) diff --git a/src/video/x11/SDL_x11opengl.c b/src/video/x11/SDL_x11opengl.c index 1e94b041cd2e3..c46710f941b48 100644 --- a/src/video/x11/SDL_x11opengl.c +++ b/src/video/x11/SDL_x11opengl.c @@ -373,6 +373,16 @@ X11_GL_InitExtensions(_THIS) (int (*)(int)) X11_GL_GetProcAddress(_this, "glXSwapIntervalSGI"); } + /* Check for GLX_ARB_create_context */ + if (HasExtension("GLX_ARB_create_context", extensions)) { + _this->gl_data->glXCreateContextAttribsARB = + (GLXContext (*)(Display*,GLXFBConfig,GLXContext,Bool,const int *)) + X11_GL_GetProcAddress(_this, "glXCreateContextAttribsARB"); + _this->gl_data->glXChooseFBConfig = + (GLXFBConfig *(*)(Display *, int, const int *, int *)) + X11_GL_GetProcAddress(_this, "glXChooseFBConfig"); + } + /* Check for GLX_EXT_visual_rating */ if (HasExtension("GLX_EXT_visual_rating", extensions)) { _this->gl_data->HAS_GLX_EXT_visual_rating = SDL_TRUE; @@ -576,7 +586,6 @@ X11_GL_CreateContext(_THIS, SDL_Window * window) XVisualInfo v, *vinfo; int n; GLXContext context = NULL, share_context; - PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribs = NULL; if (_this->gl_config.share_with_current_context) { share_context = (GLXContext)SDL_GL_GetCurrentContext(); @@ -601,78 +610,52 @@ X11_GL_CreateContext(_THIS, SDL_Window * window) context = _this->gl_data->glXCreateContext(display, vinfo, share_context, True); } else { - /* If we want a GL 3.0 context or later we need to get a temporary - context to grab the new context creation function */ - GLXContext temp_context = - _this->gl_data->glXCreateContext(display, vinfo, NULL, True); - if (temp_context) { - /* max 8 attributes plus terminator */ - int attribs[9] = { - GLX_CONTEXT_MAJOR_VERSION_ARB, - _this->gl_config.major_version, - GLX_CONTEXT_MINOR_VERSION_ARB, - _this->gl_config.minor_version, - 0 - }; - int iattr = 4; - - /* SDL profile bits match GLX profile bits */ - if( _this->gl_config.profile_mask != 0 ) { - attribs[iattr++] = GLX_CONTEXT_PROFILE_MASK_ARB; - attribs[iattr++] = _this->gl_config.profile_mask; - } + /* max 8 attributes plus terminator */ + int attribs[9] = { + GLX_CONTEXT_MAJOR_VERSION_ARB, + _this->gl_config.major_version, + GLX_CONTEXT_MINOR_VERSION_ARB, + _this->gl_config.minor_version, + 0 + }; + int iattr = 4; + + /* SDL profile bits match GLX profile bits */ + if( _this->gl_config.profile_mask != 0 ) { + attribs[iattr++] = GLX_CONTEXT_PROFILE_MASK_ARB; + attribs[iattr++] = _this->gl_config.profile_mask; + } - /* SDL flags match GLX flags */ - if( _this->gl_config.flags != 0 ) { - attribs[iattr++] = GLX_CONTEXT_FLAGS_ARB; - attribs[iattr++] = _this->gl_config.flags; - } + /* SDL flags match GLX flags */ + if( _this->gl_config.flags != 0 ) { + attribs[iattr++] = GLX_CONTEXT_FLAGS_ARB; + attribs[iattr++] = _this->gl_config.flags; + } + + attribs[iattr++] = 0; + + /* Get a pointer to the context creation function for GL 3.0 */ + if (!_this->gl_data->glXCreateContextAttribsARB) { + SDL_SetError("OpenGL 3.0 and later are not supported by this system"); + } else { + int glxAttribs[64]; + + /* Create a GL 3.x context */ + GLXFBConfig *framebuffer_config = NULL; + int fbcount = 0; - attribs[iattr++] = 0; + X11_GL_GetAttributes(_this,display,screen,glxAttribs,64,SDL_TRUE); - /* Get a pointer to the context creation function for GL 3.0 */ - glXCreateContextAttribs = - (PFNGLXCREATECONTEXTATTRIBSARBPROC) _this->gl_data-> - glXGetProcAddress((GLubyte *) - "glXCreateContextAttribsARB"); - if (!glXCreateContextAttribs) { - SDL_SetError("GL 3.x is not supported"); - context = temp_context; + if (!_this->gl_data->glXChooseFBConfig + || !(framebuffer_config = + _this->gl_data->glXChooseFBConfig(display, + DefaultScreen(display), glxAttribs, + &fbcount))) { + SDL_SetError("No good framebuffers found. OpenGL 3.0 and later unavailable"); } else { - int glxAttribs[64]; - - /* Create a GL 3.x context */ - GLXFBConfig *framebuffer_config = NULL; - int fbcount = 0; - GLXFBConfig *(*glXChooseFBConfig) (Display * disp, - int screen, - const int *attrib_list, - int *nelements); - - glXChooseFBConfig = - (GLXFBConfig * - (*)(Display *, int, const int *, - int *)) _this->gl_data-> - glXGetProcAddress((GLubyte *) "glXChooseFBConfig"); - - X11_GL_GetAttributes(_this,display,screen,glxAttribs,64,SDL_TRUE); - - if (!glXChooseFBConfig - || !(framebuffer_config = - glXChooseFBConfig(display, - DefaultScreen(display), glxAttribs, - &fbcount))) { - SDL_SetError - ("No good framebuffers found. GL 3.x disabled"); - context = temp_context; - } else { - context = - glXCreateContextAttribs(display, + context = _this->gl_data->glXCreateContextAttribsARB(display, framebuffer_config[0], share_context, True, attribs); - _this->gl_data->glXDestroyContext(display, - temp_context); - } } } } diff --git a/src/video/x11/SDL_x11opengl.h b/src/video/x11/SDL_x11opengl.h index ed7f292d4521f..b3410fd46242e 100644 --- a/src/video/x11/SDL_x11opengl.h +++ b/src/video/x11/SDL_x11opengl.h @@ -40,6 +40,8 @@ struct SDL_GLDriverData void *(*glXGetProcAddress) (const GLubyte*); XVisualInfo *(*glXChooseVisual) (Display*,int,int*); GLXContext (*glXCreateContext) (Display*,XVisualInfo*,GLXContext,Bool); + GLXContext (*glXCreateContextAttribsARB) (Display*,GLXFBConfig,GLXContext,Bool,const int *); + GLXFBConfig *(*glXChooseFBConfig) (Display*,int,const int *,int *); void (*glXDestroyContext) (Display*, GLXContext); Bool(*glXMakeCurrent) (Display*,GLXDrawable,GLXContext); void (*glXSwapBuffers) (Display*, GLXDrawable);