Do not overdraw

This commit is contained in:
neauoire 2021-09-30 19:35:22 -07:00
parent 765724d2af
commit 243c5866ac
1 changed files with 20 additions and 15 deletions

View File

@ -41,17 +41,21 @@ ppu_set_size(Ppu *p, Uint16 width, Uint16 height)
Uint8
ppu_read(Ppu *p, Uint16 x, Uint16 y)
{
if(x < p->width && y < p->height) {
Uint32 row = (x + y * p->width) / 0x2;
Uint8 shift = !(x & 0x1) << 2;
Uint8 pix = p->pixels[row] >> shift;
if(pix & 0x0c)
pix = pix >> 2;
return pix & 0x3;
}
return 0x0;
}
void
ppu_write(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 color)
{
if(x < p->width && y < p->height) {
Uint32 row = (x + y * p->width) / 0x2;
Uint8 shift = (!(x & 0x1) << 2) + (layer << 1);
Uint8 pix = p->pixels[row];
@ -61,6 +65,7 @@ ppu_write(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 color)
p->pixels[row] = pixnew;
if(pix != pixnew)
p->reqdraw = 1;
}
}
void