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newppu: improve timing. fix vice project doom

This commit is contained in:
zeromus 2008-08-19 04:06:24 +00:00
parent f6b541ce2f
commit 83f30885a2
1 changed files with 39 additions and 37 deletions
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76
src/ppu.cpp
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@ -1808,14 +1808,16 @@ int FCEUX_PPU_Loop(int skip) {
}
{
//vblank
PPU_status |= 0x80;
if(VBlankON) TriggerNMI();
//TRICKY:
//even though the timing doc says that every scanline is 1364 except for the first dummy scanline,
//i need these to be 1360 in order to get marble madness and pirates! to work.
runppu(20*1360);
runppu(1*1360);
PPU_status |= 0x80;
runppu(48);
if(VBlankON) TriggerNMI();
runppu(19*1360-48);
//no longer in vblank
PPU_status &= ~0x80;
@ -1902,46 +1904,46 @@ int FCEUX_PPU_Loop(int skip) {
pixelcolor = PALRAM[pixel];
//look for a sprite to be drawn
if(renderspritenow) {
bool havepixel = false;
for(int s=0;s<oamcount;s++) {
uint8* oam = oams[renderslot][s];
int x = oam[3];
if(rasterpos>=x && rasterpos<x+8) {
//build the pixel.
//fetch the LSB of the patterns
uint8 spixel = oam[4]&1;
spixel |= (oam[5]&1)<<1;
bool havepixel = false;
for(int s=0;s<oamcount;s++) {
uint8* oam = oams[renderslot][s];
int x = oam[3];
if(rasterpos>=x && rasterpos<x+8) {
//build the pixel.
//fetch the LSB of the patterns
uint8 spixel = oam[4]&1;
spixel |= (oam[5]&1)<<1;
//shift down the patterns so the next pixel is in the LSB
oam[4] >>= 1;
oam[5] >>= 1;
//shift down the patterns so the next pixel is in the LSB
oam[4] >>= 1;
oam[5] >>= 1;
//bail out if we already have a pixel from a higher priority sprite
if(havepixel) continue;
if(!renderspritenow) continue;
//transparent pixel bailout
if(spixel==0) continue;
//bail out if we already have a pixel from a higher priority sprite
if(havepixel) continue;
//spritehit:
//1. is it sprite#0?
//2. is the bg pixel nonzero?
//then, it is spritehit.
if(oam[6] == 0 && pixel != 0)
PPU_status |= 0x40;
//transparent pixel bailout
if(spixel==0) continue;
havepixel = true;
//spritehit:
//1. is it sprite#0?
//2. is the bg pixel nonzero?
//then, it is spritehit.
if(oam[6] == 0 && pixel != 0)
PPU_status |= 0x40;
//priority handling
if(oam[2]&0x20) {
//behind background:
if((pixel&3)!=0) continue;
}
havepixel = true;
//bring in the palette bits and palettize
spixel |= (oam[2]&3)<<2;
pixelcolor = PALRAM[0x10+spixel];
//priority handling
if(oam[2]&0x20) {
//behind background:
if((pixel&3)!=0) continue;
}
//bring in the palette bits and palettize
spixel |= (oam[2]&3)<<2;
pixelcolor = PALRAM[0x10+spixel];
}
}
@ -2083,7 +2085,7 @@ int FCEUX_PPU_Loop(int skip) {
//idle for one line
//why 1360? see the note up top at vblank
runppu(1360);
runppu(1364);
framectr++;