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x11: Make a sacrificial glX context to check for extensions during init.

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This is necessary because we need to see if GLES compat extensions exist.

All of this code (including ShouldUseTextureFramebuffer()) should be
revisited after 2.0.6 ships; ideally we don't make throwaway contexts if
we can avoid it...but maybe we can't. I hear Vulkan is pretty cool.

Fixes Bugzilla #3725.
This commit is contained in:
Ryan C. Gordon 2017-09-01 13:27:53 -04:00
parent 20207abf80
commit 507659c6ac
2 changed files with 41 additions and 10 deletions
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8
src/video/SDL_video.c
View file

@ -2941,8 +2941,8 @@ SDL_GL_ExtensionSupported(const char *extension)
void
SDL_GL_DeduceMaxSupportedESProfile(int* major, int* minor)
{
/* This function breaks games because OpenGL functions are being called before a context is current - see bug 3725 */
#if 0
/* THIS REQUIRES AN EXISTING GL CONTEXT THAT HAS BEEN MADE CURRENT. */
/* Please refer to https://bugzilla.libsdl.org/show_bug.cgi?id=3725 for discussion. */
#if SDL_VIDEO_OPENGL || SDL_VIDEO_OPENGL_ES || SDL_VIDEO_OPENGL_ES2
/* XXX This is fragile; it will break in the event of release of
* new versions of OpenGL ES.
@ -2961,10 +2961,6 @@ SDL_GL_DeduceMaxSupportedESProfile(int* major, int* minor)
*minor = 0;
}
#endif
#else
*major = 2;
*minor = 0;
#endif /* 0 */
}
void

43
src/video/x11/SDL_x11opengl.c
View file

@ -331,9 +331,32 @@ X11_GL_InitExtensions(_THIS)
{
Display *display = ((SDL_VideoData *) _this->driverdata)->display;
const int screen = DefaultScreen(display);
XVisualInfo *vinfo;
XSetWindowAttributes xattr;
Window w;
GLXContext context;
const char *(*glXQueryExtensionsStringFunc) (Display *, int);
const char *extensions;
vinfo = X11_GL_GetVisual(_this, display, screen);
if (!vinfo) {
return;
}
xattr.background_pixel = 0;
xattr.border_pixel = 0;
xattr.colormap =
X11_XCreateColormap(display, RootWindow(display, screen), vinfo->visual,
AllocNone);
w = X11_XCreateWindow(display, RootWindow(display, screen), 0, 0, 32, 32, 0,
vinfo->depth, InputOutput, vinfo->visual,
(CWBackPixel | CWBorderPixel | CWColormap), &xattr);
context = _this->gl_data->glXCreateContext(display, vinfo, NULL, True);
if (context) {
_this->gl_data->glXMakeCurrent(display, w, context);
}
X11_XFree(vinfo);
glXQueryExtensionsStringFunc =
(const char *(*)(Display *, int)) X11_GL_GetProcAddress(_this,
"glXQueryExtensionsString");
@ -391,10 +414,14 @@ X11_GL_InitExtensions(_THIS)
/* Check for GLX_EXT_create_context_es2_profile */
if (HasExtension("GLX_EXT_create_context_es2_profile", extensions)) {
SDL_GL_DeduceMaxSupportedESProfile(
&_this->gl_data->es_profile_max_supported_version.major,
&_this->gl_data->es_profile_max_supported_version.minor
);
/* this wants to call glGetString(), so it needs a context. */
/* !!! FIXME: it would be nice not to make a context here though! */
if (context) {
SDL_GL_DeduceMaxSupportedESProfile(
&_this->gl_data->es_profile_max_supported_version.major,
&_this->gl_data->es_profile_max_supported_version.minor
);
}
}
/* Check for GLX_ARB_context_flush_control */
@ -411,6 +438,14 @@ X11_GL_InitExtensions(_THIS)
if (HasExtension("GLX_ARB_create_context_no_error", extensions)) {
_this->gl_data->HAS_GLX_ARB_create_context_no_error = SDL_TRUE;
}
if (context) {
_this->gl_data->glXMakeCurrent(display, None, NULL);
_this->gl_data->glXDestroyContext(display, context);
}
X11_XDestroyWindow(display, w);
X11_PumpEvents(_this);
}
/* glXChooseVisual and glXChooseFBConfig have some small differences in