(This is the documentation for SDL3, which is the current stable version. SDL2 was the previous version!)

SDL_MapSurfaceRGBA

Map an RGBA quadruple to a pixel value for a surface.

Header File

Syntax

Uint32 SDL_MapSurfaceRGBA(SDL_Surface *surface, Uint8 r, Uint8 g, Uint8 b, Uint8 a);

Function Parameters

SDL_Surface *	surface	the surface to use for the pixel format and palette.
Uint8	r	the red component of the pixel in the range 0-255.
Uint8	g	the green component of the pixel in the range 0-255.
Uint8	b	the blue component of the pixel in the range 0-255.
Uint8	a	the alpha component of the pixel in the range 0-255.

Return Value

(Uint32) Returns a pixel value.

Remarks

This function maps the RGBA color value to the specified pixel format and returns the pixel value best approximating the given RGBA color value for the given pixel format.

If the surface pixel format has no alpha component the alpha value will be ignored (as it will be in formats with a palette).

If the surface has a palette, the index of the closest matching color in the palette will be returned.

If the pixel format bpp (color depth) is less than 32-bpp then the unused upper bits of the return value can safely be ignored (e.g., with a 16-bpp format the return value can be assigned to a Uint16, and similarly a Uint8 for an 8-bpp format).

Version

This function is available since SDL 3.1.3.