#include <stdexcept>
#include "SDL2/SDL_video.h"
-namespace {
-
-SDL_Surface *apply_alpha(SDL_Surface *src, float alpha_factor)
-{
- // FIXME: This is really slow
- assert(src->format->Amask);
- int alpha = (int) (alpha_factor * 256);
- SDL_Surface *dst = SDL_CreateRGBSurface(src->flags, src->w, src->h, src->format->BitsPerPixel, src->format->Rmask, src->format->Gmask, src->format->Bmask, src->format->Amask);
- int bpp = dst->format->BytesPerPixel;
- if(SDL_MUSTLOCK(src))
- {
- SDL_LockSurface(src);
- }
- if(SDL_MUSTLOCK(dst))
- {
- SDL_LockSurface(dst);
- }
- for(int y = 0;y < dst->h;y++) {
- for(int x = 0;x < dst->w;x++) {
- Uint8 *srcpixel = (Uint8 *) src->pixels + y * src->pitch + x * bpp;
- Uint8 *dstpixel = (Uint8 *) dst->pixels + y * dst->pitch + x * bpp;
- Uint32 mapped = 0;
- switch(bpp) {
- case 1:
- mapped = *srcpixel;
- break;
- case 2:
- mapped = *(Uint16 *)srcpixel;
- break;
- case 3:
-#if SDL_BYTEORDER == SDL_BIG_ENDIAN
- mapped |= srcpixel[0] << 16;
- mapped |= srcpixel[1] << 8;
- mapped |= srcpixel[2] << 0;
-#else
- mapped |= srcpixel[0] << 0;
- mapped |= srcpixel[1] << 8;
- mapped |= srcpixel[2] << 16;
-#endif
- break;
- case 4:
- mapped = *(Uint32 *)srcpixel;
- break;
- }
- Uint8 r, g, b, a;
- SDL_GetRGBA(mapped, src->format, &r, &g, &b, &a);
- mapped = SDL_MapRGBA(dst->format, r, g, b, (a * alpha) >> 8);
- switch(bpp) {
- case 1:
- *dstpixel = mapped;
- break;
- case 2:
- *(Uint16 *)dstpixel = mapped;
- break;
- case 3:
-#if SDL_BYTEORDER == SDL_BIG_ENDIAN
- dstpixel[0] = (mapped >> 16) & 0xff;
- dstpixel[1] = (mapped >> 8) & 0xff;
- dstpixel[2] = (mapped >> 0) & 0xff;
-#else
- dstpixel[0] = (mapped >> 0) & 0xff;
- dstpixel[1] = (mapped >> 8) & 0xff;
- dstpixel[2] = (mapped >> 16) & 0xff;
-#endif
- break;
- case 4:
- *(Uint32 *)dstpixel = mapped;
- break;
- }
- }
- }
- if(SDL_MUSTLOCK(dst))
- {
- SDL_UnlockSurface(dst);
- }
- if(SDL_MUSTLOCK(src))
- {
- SDL_UnlockSurface(src);
- }
- return dst;
-}
-
-} // namespace
-
SDLRenderer::SDLRenderer() :
window(),
renderer()