Provide a convenient way to convert to Surface's pixel format

[ilyapopov]

Suppose I want to fill a rectangle with some color. FillRect member function expects a color in surface's format. There is conversion function, SDL_MapRGB, but it expects SDL_PixelFormat*. Surface::GetFormat, however, returns only SDL_PixelFormat::format, not the whole structure.

What is the preferred way to convert RGB values to surface's color that FillRect expects?

surface.FillRect(rect, SDL_MapRGB(???, r, g, b));

Shall a method be provided to convert RGB to color value:

Surface::MapRGB(Uint8 r, Uint8 g, Uint8 b);

Or even a FillRect overload taking RGB values?

[ooxi]

👍

[AMDmi3]

Yes, I've had that in plans. Not yet figured out a consistent way to handle both integer pixelformat and SDL_PixelFormat structure everywhere (renderer, texture, surface). Regarding the color, MapRGB should likely be a method of a SDL_PixelFormat wrapper. I'll try to handle this next year :)

[ilyapopov]

Is this a correct workaround?

SDL_PixelFormat fmt* SDL_AllocFormat(surface.Format());
surface.FillRect(rect, SDL_MapRGB(fmt, r, g, b));
SDL_FreeFormat(fmt);

[ilyapopov]

Or better this:

std::unique_ptr<SDL_PixelFormat, void (*)(SDL_PixelFormat *)> fmt(
    SDL_AllocFormat(surface.Format()), SDL_FreeFormat);
surface.FillRect(rect, SDL_MapRGB(fmt.get(), r, g, b));

[AMDmi3]

You don't have to allocate a new pixel format as Surface already contains one.

Probably something like this:

surface.FillRect(rect, SDL_MapRGB(surface.Get()->format, r, g, b));

[ilyapopov]

Thanks! I did not realize i can access format through Get().