This kicks in if the platform doesn't support vsync directly, or if the present fails for some reason (e.g. minimized on some platforms)
Fixes https://github.com/libsdl-org/SDL/issues/5134
There is supposedly an OpenGL ES2 target that does not support precision specifiers. However, the existing logic to detect this is currently broken in two ways:
1) There's a typo of the `#ifdef` as `#if`.
2) Checking for `GL_FRAGMENT_PRECISION_HIGH` can not be the correct way to detect this platform. Other targets, including some desktops, will also not have this defined (for various reasons).
Because some of the shader code is missing precision specifiers, and because a default is ONLY provided if `GL_FRAGMENT_PRECISION_HIGH` is set, these other targets break.
Instead of 'hard-coding' the prologue string into shaders in the C source, use our ability to provide a list of strings to `glShaderSource` instead, leaving the determination to run-time.
This commit closes https://github.com/libsdl-org/SDL/pull/6182
- Factorize PrepQueueCmdDraw{,DrawTexture,Solid) into one single function
- Change SDL_Texture/Renderer r,g,b,a Uint8 into an SDL_Color, so that it can be passed directly to RenderGeometry
- Don't automatically queue a SET_DRAW_COLOR cmd for RenderGeometry (and update GLES2 renderer)
One place known to differ in a significant way is a single line segment that
starts and ends on the same point; the GL renderers will light up a single
pixel here, whereas the software renderer will not. My current belief is this
is a bug in the software renderer, based on the wording of the docs:
"SDL_RenderDrawLine() draws the line to include both end points."
You can see an example program that triggers that difference in Bug #2006.
As it stands, the GL renderers might _also_ render diagonal lines differently,
as the the Bresenham step might vary between implementations (one does three
pixels and then two, the other does two and then three, etc). But this patch
causes those lines to start and end on the correct pixel, and that's the best
we can do, and all anyone really needs here.
Not closing any bugs with this patch (yet!), but here are several that it
appears to fix. If no other corner cases pop up, we'll call this done.
Reference Bug #2006.
Reference Bug #1626.
Reference Bug #4001.
...and probably others...
Currently, if an application wants to toggle VSync, they'd have to tear
down the renderer and recreate it. This patch fixes that by letting
applications call SDL_RenderSetVSync().
This is the same as the patch in #3673, except it applies to all
renderers (including PSP, even thought it seems that the VSync flag is
disabled for that renderer). Furthermore, the renderer flags also change
as well, which #3673 didn't do. It is also an API instead of using hint
callbacks (which could be potentially dangerous).
Closes#3673.
