Matthias Bentrup 2012-08-09 12:53:17 PDT
With OpenGL 4.3 the ARB added a new context flag for context reset isolation
and renamed the existing ES2 profile bit to ES profile bit, as it can be used
to request GLES 3 compatible contexts, too.
This patch adds these changes to SDL on Linux and Windows.
Also SDL lacks the ability to create shared contexts. This patch also adds a
new GL attribute to enable context sharing. As casting a GL context to int is
not portable, I added only a boolean attribute
SDL_GL_SHARE_WITH_CURRENT_CONTEXT, which makes the new context share resources
with the context current on the creating thread.
This required a small public API change: SDL_GL_SetSwapInterval() now accepts
negative values, and SDL_GL_GetSwapInterval() doesn't report errors anymore
(if it can't work, it'll return zero as a reasonable default).
If you need to test for errors, such as a lack of swap_control_tear support,
check the results of SDL_GL_SetSwapInterval() when you set your desired
value.
From Scott Percival
Okay, I think I have something for this. Tested it on GL and GLES
machines, it seems to work okay.
- Add a new SDL GL attribute SDL_GL_CONTEXT_EGL:
- Only useful for the X11 video driver at the moment
- Set to 1 for an EGL context, 0 to use the default for the video driver
- Default is 0, unless library is built for EGL only
- Should be set after SDL init, but before window/context
creation (i.e. same place you'd specify attributes for major/minor GL
version)
- After a lot of agony pondering the least-terrible way to go about
it, made it so that X11_GL_LoadLibrary and X11_GLES_LoadLibrary check
SDL_GL_CONTEXT_EGL. If no GL context exists yet, and the attribute
choice doesn't match with the checking function, then it changes all
the function pointers in the video driver and passes control on to the
new LoadLibrary method.
- Likewise, make X11_CreateWindow check this attribute before firing
off a call to X11_GL_GetVisual/X11_GLES_GetVisual
- Added a sanity check to the start of X11_GL_LoadLibrary
- Tidied up SDL_x11opengles.h
- Moved ownership of the gles_data structure over to
X11_GLES_LoadLibrary/UnloadLibrary
- Should incorporate the 3 fixes posted by Andre Heider
This is obviously quite a bit to take in, but is (at least) a proof of
concept for the approach I think EGL/GLX mingling should take. Any
comments/criticism is much appreciated.
Matthias Bentrup 2011-10-30 03:58:24 PDT
I've updated the context creation patch to include the bugfixes by Martin
Schreiber and also included a profile bit to request a ES2 compatible profile.
The wgl context creation may use 2 call to wglChoosePixelFormat if no
acceleration attribute is selected, this should work around a bug with buggy
AMD drivers (see #1254).
Matthew Orlando to Sam
Someone asked in IRC whether they should free the surface from SDL_GetWindowSurface. The doc comment is a bit vague so i checked the code and revised the comment.
The render viewport is automatically re-centered when the window changes size, so applications that don't care will not have to handle recalculating their rendering coordinates.
Fixed API for drawing and filling multiple rectangles - the parameter should be an array of rects, not an array of pointers to rects.
Fixed API for updating window rects for consistency with other APIs - the order is pointer to array followed by count in array.
There's a new event that's always sent when the window changes size, and that event is what the renderers listen for to determine if they need to rebind their context.
tag: tip
user: Martin Decky <martin@decky.cz>
date: Sat Feb 12 20:53:06 2011 +0100
summary: improve header files compatibility with SDL 1.2 applications (namely QEMU)
The software renderer has been re-routed to use the framebuffer interface, which makes it possible to have software rendering available even on simple ports.
Renamed SDL_RenderPoint() and SDL_RenderLine() to SDL_RenderDrawPoint() and SDL_RenderDrawLine().
Added API for rectangle drawing (as opposed to filling)
Added placeholder API functions for circles and ellipses ... I'm not sure whether these will stay.
Optimized software line drawing quite a bit.
Added support for Wu's anti-aliased line drawing, currently disabled by default.
