On 16/04/2021 13:17, Huw Davies wrote:
On Thu, Apr 08, 2021 at 04:11:04PM +0300, Gabriel Ivăncescu wrote:
Signed-off-by: Gabriel Ivăncescu gabrielopcode@gmail.com
dlls/gdi32/dibdrv/primitives.c | 65 +++++++++++++++++++++++++--------- 1 file changed, 49 insertions(+), 16 deletions(-)
diff --git a/dlls/gdi32/dibdrv/primitives.c b/dlls/gdi32/dibdrv/primitives.c index 0a5f7e5..be68058 100644 --- a/dlls/gdi32/dibdrv/primitives.c +++ b/dlls/gdi32/dibdrv/primitives.c @@ -3497,22 +3497,48 @@ static void convert_to_16(dib_info *dst, const dib_info *src, const RECT *src_re } }
-static inline BOOL color_tables_match(const dib_info *d1, const dib_info *d2) +/*
- To lookup RGB values into nearest color in the color table, Windows uses 5-bits of the RGB
- at the "center" of the RGB cube, presumably to do a similar lookup cache. The lowest 3 bits
- of the color are thus set to halfway (0x04) and then it's used in the distance calculation
- to the exact color in the color table. We exploit this as well to create a lookup cache.
+*/ +struct rgb_lookup_colortable_ctx +{
- const dib_info *dib;
- BYTE map[32768];
- BYTE valid[32768 / 8];
+};
+static void rgb_lookup_colortable_init(const dib_info *dib, struct rgb_lookup_colortable_ctx *ctx) {
- if (!d1->color_table || !d2->color_table) return (!d1->color_table && !d2->color_table);
- return !memcmp(d1->color_table, d2->color_table, (1 << d1->bit_count) * sizeof(d1->color_table[0]));
- ctx->dib = dib;
- memset(ctx->valid, 0, sizeof(ctx->valid)); }
-static inline DWORD rgb_lookup_colortable(const dib_info *dst, BYTE r, BYTE g, BYTE b) +static inline BYTE rgb_lookup_colortable(struct rgb_lookup_colortable_ctx *ctx, BYTE r, BYTE g, BYTE b) {
- /* Windows reduces precision to 5 bits, probably in order to build some sort of lookup cache */
- return rgb_to_pixel_colortable( dst, (r & ~7) + 4, (g & ~7) + 4, (b & ~7) + 4 );
- unsigned pos = (r >> 3) | (g & ~7) << 2 | (b & ~7) << 7;
- if (!(ctx->valid[pos / 8] & (1 << pos % 8)))
- {
ctx->valid[pos / 8] |= 1 << pos % 8;ctx->map[pos] = rgb_to_pixel_colortable(ctx->dib, (r & ~7) + 4, (g & ~7) + 4, (b & ~7) + 4);- }
- return ctx->map[pos];
+}
I've sent in v4 of this series in which I've tweaked this a bit to give the compiler more of a chance to optimize things as well as using a lookup for the pixel masks.
With a 300x300 32-bpp -> 8-bpp BitBlt I'm getting performance slighty better than Windows if there aren't many distinct RGB values and a little worse if the entire map needs filling.
Huw.
Looks good, thanks.