man SDL_GetRGBA (Fonctions bibliothèques) - SDL_GetRGBA- Get RGBA values from a pixel in the specified pixel format.
NAME
SDL_GetRGBA- Get RGBA values from a pixel in the specified pixel format.
SYNOPSIS
#include "SDL.h" void SDL_GetRGBA(Uint32 pixel, SDL_PixelFormat *fmt, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a);
DESCRIPTION
Get RGBA component values from a pixel stored in the specified pixel format.
This function uses the entire 8-bit [0..255] range when converting color components from pixel formats with less than 8-bits per RGB component (e.g., a completely white pixel in 16-bit RGB565 format would return [0xff, 0xff, 0xff] not [0xf8, 0xfc, 0xf8]).
If the surface has no alpha component, the alpha will be returned as 0xff (100% opaque).
SEE ALSO
SDL_GetRGB, SDL_MapRGB, SDL_MapRGBA, SDL_PixelFormat