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GB Software: Special case a fast draw path for backgrounds

This commit is contained in:
Jeffrey Pfau 2016-02-14 20:08:41 -08:00
parent cd0a352a33
commit 8257c85c95
1 changed files with 28 additions and 5 deletions
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33
src/gb/renderers/software.c
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@ -179,9 +179,27 @@ static void GBVideoSoftwareRendererDrawBackground(struct GBVideoSoftwareRenderer
startX = 0;
}
int x;
for (x = startX; x < endX; ++x) {
if ((startX + sx) & 7) {
int startX2 = startX + 8 - ((startX + sx) & 7);
for (x = startX; x < startX2; ++x) {
int topX = ((x + sx) >> 3) & 0x1F;
int bottomX = 7 - ((x + sx) & 7);
int bgTile;
if (GBRegisterLCDCIsTileData(renderer->lcdc)) {
bgTile = maps[topX + topY];
} else {
bgTile = ((int8_t*) maps)[topX + topY];
}
uint8_t tileDataLower = data[(bgTile * 8 + bottomY) * 2];
uint8_t tileDataUpper = data[(bgTile * 8 + bottomY) * 2 + 1];
tileDataUpper >>= bottomX;
tileDataLower >>= bottomX;
renderer->row[x] = ((tileDataUpper & 1) << 1) | (tileDataLower & 1);
}
startX = startX2;
}
for (x = startX; x < endX; x += 8) {
int topX = ((x + sx) >> 3) & 0x1F;
int bottomX = 7 - ((x + sx) & 7);
int bgTile;
if (GBRegisterLCDCIsTileData(renderer->lcdc)) {
bgTile = maps[topX + topY];
@ -190,9 +208,14 @@ static void GBVideoSoftwareRendererDrawBackground(struct GBVideoSoftwareRenderer
}
uint8_t tileDataLower = data[(bgTile * 8 + bottomY) * 2];
uint8_t tileDataUpper = data[(bgTile * 8 + bottomY) * 2 + 1];
tileDataUpper >>= bottomX;
tileDataLower >>= bottomX;
renderer->row[x] = ((tileDataUpper & 1) << 1) | (tileDataLower & 1);
renderer->row[x + 7] = ((tileDataUpper & 1) << 1) | (tileDataLower & 1);
renderer->row[x + 6] = (tileDataUpper & 2) | ((tileDataLower & 2) >> 1);
renderer->row[x + 5] = ((tileDataUpper & 4) >> 1) | ((tileDataLower & 4) >> 2);
renderer->row[x + 4] = ((tileDataUpper & 8) >> 2) | ((tileDataLower & 8) >> 3);
renderer->row[x + 3] = ((tileDataUpper & 16) >> 3) | ((tileDataLower & 16) >> 4);
renderer->row[x + 2] = ((tileDataUpper & 32) >> 4) | ((tileDataLower & 32) >> 5);
renderer->row[x + 1] = ((tileDataUpper & 64) >> 5) | ((tileDataLower & 64) >> 6);
renderer->row[x + 0] = ((tileDataUpper & 128) >> 6) | ((tileDataLower & 128) >> 7);
}
}