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.
OpenGL leaves the final line segment open, SDL's software renderer does not,
so we need a tiny bit of trigonometry here to move one more pixel in the right
direction.
This is the OpenGL line drawing fix for Bugzilla #3182, but there's some
disagreement about what the renderers should do here, so I'm backing this out
until after 2.0.12 ships, and then we'll reevaluate all the renderer backends
to decide what's correct, and make them all work the same.
Likewise for the GLES1 and GLES2 renderers.
This solves the missing pixel at the end of a line and removes all the
heuristics for various platforms/drivers. It's possible we could still use
GL_LINE_STRIP with this and save some vertex buffer space, assuming this
doesn't upset some driver somewhere, but this seems to be a clean fix that
makes the GL renderers match the software renderer output.
Diamond-exit rule explanation:
http://graphics-software-engineer.blogspot.com/2012/04/rasterization-rules.html
Fixes Bugzilla #3182.
Konrad
This was something rather trivial to add, but asked at least several times before (I did google about it as well).
It should be possible to dynamically change scaling mode of the texture. It is actually trivial task, but until now it was only possible with a hint before creating a texture.
I needed it for my game as well, so I took the liberty of writing it myself.
This patch adds following functions:
SDL_SetTextureScaleMode(SDL_Texture * texture, SDL_ScaleMode scaleMode);
SDL_GetTextureScaleMode(SDL_Texture * texture, SDL_ScaleMode *scaleMode);
That way you can change texture scaling on the fly.
Olli-Samuli Lehmus
If one creates a window with the SDL_WINDOW_FULLSCREEN_DESKTOP flag, and creates a render target with SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear"), and afterwards sets SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "nearest"), after minimizing the window, the scale quality hint is lost on the render target. Textures however do keep their interpolation modes.
SDL now builds with gcc 7.2 with the following command line options:
-Wall -pedantic-errors -Wno-deprecated-declarations -Wno-overlength-strings --std=c99
Sam Lantinga
Sylvain
Alex Szpakowski
Ryan C. Gordon
Misa
sezero