1 files changed, 7 insertions(+), 4 deletions(-)

M src/devices/ppu.c

@@ 46,12 46,15 @@ ppu_pixel(Ppu *p, uint8_t fg, uint16_t x, uint16_t y, uint8_t color)
 {
 	if(x >= WIDTH || y >= HEIGHT) return;
 	int offset = y * STRIDE_WORDS + x / 32;
+	int i = offset * 3 + fg * 2;
 	uint32_t mask = 1 << ((x & 0x18) + (7 - (x & 0x7)));
+	uint32_t before = p->pixels[i];
 	if(color & 0x01)
-		p->pixels[offset * 3 + fg * 2] |= mask;
+		p->pixels[i] |= mask;
 	else
-		p->pixels[offset * 3 + fg * 2] &= ~mask;
-	render(p, offset, 1);
+		p->pixels[i] &= ~mask;
+	if(before != p->pixels[i])
+		render(p, offset, 1);
 }
 
 void


@@ 59,7 62,7 @@ screen_blit(Ppu *p, uint8_t fg, uint16_t x, uint16_t y, uint8_t *sprite, uint8_t
 {
 	int v, h, opaque = (color % 5) || !color;
 	for(v = 0; v < 8; v++) {
-		uint16_t c = sprite[v] | (twobpp ? sprite[v + 8] : 0) << 8;
+		uint16_t c = sprite[v] | (twobpp ? (sprite[v + 8] << 8) : 0);
 		for(h = 7; h >= 0; --h, c >>= 1) {
 			uint8_t ch = (c & 1) | ((c >> 7) & 2);
 			if(opaque || ch)