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
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