- int x, y;
- uint8_t *buf = (uint8_t *)(gpScreenBuffer + Y*giScreenWidth + X);
- uint8_t *data;
-
- // Sanity please
- if( !Image )
- return ;
-
- // Bounds Check
- if( X >= giScreenWidth ) return ;
- if( Y >= giScreenHeight ) return ;
-
- // Wrap to image size
- if( W > Image->Width ) W = Image->Width;
- if( H > Image->Height ) H = Image->Height;
-
- // Wrap to screen size
- if( X + W > giScreenWidth ) W = giScreenWidth - X;
- if( Y + H > giScreenHeight ) H = giScreenHeight - Y;
-
- // Do the render
- data = Image->Data;
- switch( Image->Format )
- {
- case IMGFMT_BGRA:
- for( y = 0; y < H; y ++ )
- {
- int r, g, b, a; // New
- int or, og, ob; // Original
- for( x = 0; x < W; x ++ )
- {
- b = data[x*4+0]; g = data[x*4+1]; r = data[x*4+2]; a = data[x*4+3];
- if( a == 0 ) continue; // 100% transparent
- ob = buf[x*4+0]; og = buf[x*4+1]; or = buf[x*4+2];
- // Handle Alpha
- switch(a)
- {
- // Transparent: Handled above
- // Solid
- case 0xFF: break;
- // Half
- case 0x80:
- r = (or + r) / 2;
- g = (og + g) / 2;
- b = (ob + b) / 2;
- break;
- // General
- default:
- r = (or * (255-a) + r * a) / 255;
- g = (og * (255-a) + g * a) / 255;
- b = (ob * (255-a) + b * a) / 255;
- break;
- }
- buf[x*4+0] = b; buf[x*4+1] = g; buf[x*4+2] = r;
- }
- data += Image->Width * 4;
- buf += giScreenWidth * 4;
- }
- break;
-
- // RGB
- case IMGFMT_RGB:
- for( y = 0; y < H; y ++ )
- {
- for( x = 0; x < W; x ++ )
- {
- buf[x*4+0] = data[x*3+2]; // Blue
- buf[x*4+1] = data[x*3+1]; // Green
- buf[x*4+2] = data[x*3+0]; // Red
- }
- data += W * 3;
- buf += giScreenWidth * 4;
- }
- break;
- default:
- _SysDebug("ERROR: Unknown image format %i\n", Image->Format);
- break;
+ uint16_t ao,ro,go,bo;
+ uint16_t an,rn,gn,bn;
+ if( _alpha == 0 ) return _orig;
+ if( _alpha == 255 ) return _new;
+
+ ao = (_orig >> 24) & 0xFF;
+ ro = (_orig >> 16) & 0xFF;
+ go = (_orig >> 8) & 0xFF;
+ bo = (_orig >> 0) & 0xFF;
+
+ an = (_new >> 24) & 0xFF;
+ rn = (_new >> 16) & 0xFF;
+ gn = (_new >> 8) & 0xFF;
+ bn = (_new >> 0) & 0xFF;
+
+ if( _alpha == 0x80 ) {
+ ao = (ao + an) / 2;
+ ro = (ro + rn) / 2;
+ go = (go + gn) / 2;
+ bo = (bo + bn) / 2;
+ }
+ else {
+ ao = ao*(255-_alpha) + an*_alpha;
+ ro = ro*(255-_alpha) + rn*_alpha;
+ go = go*(255-_alpha) + gn*_alpha;
+ bo = bo*(255-_alpha) + bn*_alpha;
+ ao /= 255*2;
+ ro /= 255*2;
+ go /= 255*2;
+ bo /= 255*2;