SDLOutputSurface.cc

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#include "SDLOutputSurface.hh"
#include "unreachable.hh"
 
namespace openmsx {
 
SDLDirectPixelAccess::SDLDirectPixelAccess(SDL_Surface* surface_)
        : surface(surface_)
{
        assert(surface);
        if (SDL_MUSTLOCK(surface)) {
                // Note: we ignore the return value from SDL_LockSurface()
                SDL_LockSurface(surface);
        }
}
 
SDLDirectPixelAccess::~SDLDirectPixelAccess()
{
        if (SDL_MUSTLOCK(surface)) {
                SDL_UnlockSurface(surface);
        }
}
 
 
void SDLOutputSurface::setSDLPixelFormat(const SDL_PixelFormat& format)
{
        auto bpp = format.BitsPerPixel;
 
        auto Rmask = format.Rmask;
        auto Rshift = format.Rshift;
        auto Rloss = format.Rloss;
 
        auto Gmask = format.Gmask;
        auto Gshift = format.Gshift;
        auto Gloss = format.Gloss;
 
        auto Bmask = format.Bmask;
        auto Bshift = format.Bshift;
        auto Bloss = format.Bloss;
 
        auto Amask = format.Amask;
        auto Ashift = format.Ashift;
        auto Aloss = format.Aloss;
 
        // TODO is this still needed with SDL2?
        // SDL sets an alpha channel only for GL modes. We want an alpha channel
        // for all 32bpp output surfaces, so we add one ourselves if necessary.
        if (bpp == 32 && Amask == 0) {
                unsigned rgbMask = Rmask | Gmask | Bmask;
                if ((rgbMask & 0x000000FF) == 0) {
                        Amask  = 0x000000FF;
                        Ashift = 0;
                        Aloss  = 0;
                } else if ((rgbMask & 0xFF000000) == 0) {
                        Amask  = 0xFF000000;
                        Ashift = 24;
                        Aloss  = 0;
                } else {
                        UNREACHABLE;
                }
        }
 
        setPixelFormat(PixelFormat(bpp,
                                   Rmask, Rshift, Rloss,
                                   Gmask, Gshift, Gloss,
                                   Bmask, Bshift, Bloss,
                                   Amask, Ashift, Aloss));
}
 
} // namespace openmsx