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GRAPHICS: Support Floyd dithering for RGB332

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RGB332 is a special case of CLUT8 but RGB332 support allows to skip passing
palette explicitly and speeds up the dithering
This commit is contained in:
Vladimir Serbinenko 2023-01-05 10:56:38 +01:00
parent 6a063e1108
commit b9aa479bba
2 changed files with 52 additions and 25 deletions
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75
graphics/surface.cpp
View File

@ -558,7 +558,8 @@ Graphics::Surface *Surface::convertTo(const PixelFormat &dstFormat, const byte *
// We are here when we are converting from a higher bpp or palettes are different
if (dstFormat.bytesPerPixel == 1) {
ditherFloyd(srcPalette, srcPaletteCount, surface, dstPalette, dstPaletteCount, method);
ditherFloyd(srcPalette, srcPaletteCount, surface, dstPalette, dstPaletteCount, method,
dstFormat);
return surface;
}
@ -732,13 +733,8 @@ static void updatePixel(byte *surf, int x, int y, int w, int h, int qr, int qg,
ptr[2] = CLIP(ptr[2] + qb * qq / qdiv, 0, 255);
}
void Surface::ditherFloyd(const byte *srcPalette, int srcPaletteCount, Surface *dstSurf, const byte *dstPalette, int dstPaletteCount, DitherMethod method) const {
assert(dstPalette);
PaletteLookup _paletteLookup;
_paletteLookup.setPalette(dstPalette, dstPaletteCount);
void Surface::ditherFloyd(const byte *srcPalette, int srcPaletteCount, Surface *dstSurf, const byte *dstPalette, int dstPaletteCount,
DitherMethod method, const PixelFormat &dstFormat) const {
byte *tmpSurf = (byte *)malloc(w * h * 3);
int bpp = format.bytesPerPixel;
@ -903,29 +899,60 @@ void Surface::ditherFloyd(const byte *srcPalette, int srcPaletteCount, Surface *
{ nullptr, nullptr, 0 }
};
for (int y = 0; y < h; y++) {
const byte *src = &tmpSurf[y * w * 3];
byte *dst = (byte *)dstSurf->getBasePtr(0, y);
if (dstPalette) {
PaletteLookup _paletteLookup;
for (int x = 0; x < w; x++) {
byte r = src[0], g = src[1], b = src[2];
byte col = _paletteLookup.findBestColor(r, g, b);
_paletteLookup.setPalette(dstPalette, dstPaletteCount);
*dst = col;
for (int y = 0; y < h; y++) {
const byte *src = &tmpSurf[y * w * 3];
byte *dst = (byte *)dstSurf->getBasePtr(0, y);
int qr = r - dstPalette[col * 3 + 0];
int qg = g - dstPalette[col * 3 + 1];
int qb = b - dstPalette[col * 3 + 2];
for (int x = 0; x < w; x++) {
byte r = src[0], g = src[1], b = src[2];
byte col = _paletteLookup.findBestColor(r, g, b);
const DitherParams *params = algos[method].params;
*dst = col;
for (int i = 0; params[i].dx != 0 || params[i].dy != 0; i++)
updatePixel(tmpSurf, x + params[i].dx, y + params[i].dy, w, h, qr, qg, qb, params[i].qq, algos[method].qdiv);
int qr = r - dstPalette[col * 3 + 0];
int qg = g - dstPalette[col * 3 + 1];
int qb = b - dstPalette[col * 3 + 2];
src += 3;
dst++;
const DitherParams *params = algos[method].params;
for (int i = 0; params[i].dx != 0 || params[i].dy != 0; i++)
updatePixel(tmpSurf, x + params[i].dx, y + params[i].dy, w, h, qr, qg, qb, params[i].qq, algos[method].qdiv);
src += 3;
dst++;
}
}
}
} else if (dstFormat == PixelFormat(1, 3, 3, 2, 0, 5, 2, 0, 0)) {
for (int y = 0; y < h; y++) {
const byte *src = &tmpSurf[y * w * 3];
byte *dst = (byte *)dstSurf->getBasePtr(0, y);
for (int x = 0; x < w; x++) {
byte r = src[0], g = src[1], b = src[2];
byte col = (r & 0xe0) | ((g >> 3) & 0x1c) | ((b >> 6) & 3);
*dst = col;
int qr = r & 0x1f;
int qg = g & 0x1f;
int qb = b & 0x3f;
const DitherParams *params = algos[method].params;
for (int i = 0; params[i].dx != 0 || params[i].dy != 0; i++)
updatePixel(tmpSurf, x + params[i].dx, y + params[i].dy, w, h, qr, qg, qb, params[i].qq, algos[method].qdiv);
src += 3;
dst++;
}
}
} else
error("Unsupported dithering target format or missing palette");
::free(tmpSurf);
}

2
graphics/surface.h
View File

@ -361,7 +361,7 @@ public:
Graphics::Surface *convertTo(const PixelFormat &dstFormat, const byte *srcPalette = 0, int srcPaletteCount = 0, const byte *dstPalette = 0, int dstPaletteCount = 0, DitherMethod method = kDitherFloyd) const;
private:
void ditherFloyd(const byte *srcPalette, int srcPaletteCount, Surface *dstSurf, const byte *dstPalette, int dstPaletteCount, DitherMethod method) const;
void ditherFloyd(const byte *srcPalette, int srcPaletteCount, Surface *dstSurf, const byte *dstPalette, int dstPaletteCount, DitherMethod method, const PixelFormat &dstFormat) const;
public: