Ellie
I just tripped over this: stb_image when requesting 3 channels with 8-bit actually returns them as 3 bytes per pixel with no alignment, so basically 4 pixels are 12 bytes with no padding (0...2, 3...5, 6...8, and 9...11). This I would have naively expected to be called RGB888 or BGR888, since there is no "dead" unused byte as I would expect for something called e.g. RGBX8888.
However, SDL2's SDL_PIXELFORMAT_BGR888 uses 4 bytes, same as SDL_PIXELFORMAT_BGRX8888, even though the latter appears to be a longer storage format - which it isn't, internally. It's just swapped, in byte order X, B, G, R (instead of BGRX). So why isn't the macro name also swapped, as "XBGR888" instead of just "BGR888"?
I find the formats therefore named inconsistently, and unless there is a reason for this I suggest these changes:
1. deprecate SDL_PIXELFORMAT_BGR888 in favor of a new SDL_PIXELFORMAT_XBGR8888
and
2. deprecate SDL_PIXELFORMAT_RGB888 in favor of a new SDL_PIXELFORMAT_XRGB8888
zen3d
While trying to build Pixie lisp (https://github.com/pixie-lang/pixie), which uses SDL for multimedia output, the mandelbrot example won't build. The problem is that internally pixie uses a templated function to dump a value, and gcc chokes because SDL_PIXELFORMAT_RGA8888 is an anonymous enum.
I solved the problem locally by changing from:
enum {
SDL_PIXELFORMAT_UNKNOWN,
... etc. ...
SDL_PIXELFORMAT_YUYV = ... etc ...
};
to:
typedef enum {
SDL_PIXELFORMAT_UNKNOWN,
... etc. ...
SDL_PIXELFORMAT_YUYV = ... etc ...
} SDL_PIXELFORMAT_ENUM;
The net result of this change is that the enum containing SDL_PIXELFORMAT_* is no longer an anonymous enum and can now be used by a templated function.
This local change fixes Pixie lisp for me.
I did notice that you use the idiom
typedef enum {
... etc ...
} SDL_FOO;
elsewhere in your code, so that change to SDL_PIXELFORMAT doesn't look like it would have a negative impact.
Daniel Gibson
Ok, I followed the simple approach of just making SDL_PIXELFORMAT_RGBA32 an alias of SDL_PIXELFORMAT_RGBA8888/SDL_PIXELFORMAT_ABGR8888, depending on endianess. And I did the same for SDL_PIXELFORMAT_ARGB32, .._BGRA, .._ABGR.
SDL_GetPixelFormatName() will of course return SDL_PIXELFORMAT_RGBA8888 (or SDL_PIXELFORMAT_ABGR8888) instead of SDL_PIXELFORMAT_RGBA32, but as long as that's mentioned in the docs it shouldn't be a problem.
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
Alex Szpakowski
SDL Wiki Bot
Ryan C. Gordon
Sam Lantinga
Cameron Cawley
Sylvain Becker
Philipp Wiesemann