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ppu_blit: mostly cosmetic - explain blending's 4th row, gain few more cycles

This commit is contained in:
Sigrid Solveig Haflínudóttir 2021-12-25 16:26:01 +01:00
parent 8bbe5c1dfd
commit 5848fbe50b
1 changed files with 2 additions and 1 deletions
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3
src/devices/ppu.c
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@ -103,13 +103,14 @@ ppu_write(Ppu *p, Layer *layer, Uint16 x, Uint16 y, Uint8 color)
void void
ppu_blit(Ppu *p, Layer *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy, Uint8 twobpp) ppu_blit(Ppu *p, Layer *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy, Uint8 twobpp)
{ {
Uint8 opaque = blending[4][color];
Uint16 v, h; Uint16 v, h;
for(v = 0; v < 8; ++v) for(v = 0; v < 8; ++v)
for(h = 0; h < 8; ++h) { for(h = 0; h < 8; ++h) {
Uint8 ch = (sprite[v + 0] >> (7 - h)) & 0x1; Uint8 ch = (sprite[v + 0] >> (7 - h)) & 0x1;
if(twobpp) if(twobpp)
ch |= ((sprite[v + 8] >> (7 - h)) & 0x1) << 1; ch |= ((sprite[v + 8] >> (7 - h)) & 0x1) << 1;
if(ch || blending[4][color]) if(opaque || ch)
ppu_write(p, ppu_write(p,
layer, layer,
x + (flipx ? 7 - h : h), x + (flipx ? 7 - h : h),