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newppu: support the no8spritelimit feature

This commit is contained in:
zeromus 2008-08-24 04:01:00 +00:00
parent e715b79024
commit 5cbe76fca2
1 changed files with 18 additions and 8 deletions
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26
src/ppu.cpp
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@ -1838,7 +1838,7 @@ int FCEUX_PPU_Loop(int skip) {
if(PPUON) if(PPUON)
ppur.install_latches(); ppur.install_latches();
uint8 oams[2][8][7]; uint8 oams[2][64][7];
int oamcounts[2]={0,0}; int oamcounts[2]={0,0};
int oamslot=0; int oamslot=0;
int oamcount; int oamcount;
@ -1963,9 +1963,9 @@ int FCEUX_PPU_Loop(int skip) {
for(int i=0;i<64;i++) { for(int i=0;i<64;i++) {
uint8* spr = SPRAM+i*4; uint8* spr = SPRAM+i*4;
if(yp >= spr[0] && yp < spr[0]+spriteHeight) { if(yp >= spr[0] && yp < spr[0]+spriteHeight) {
//if we already have 8 sprites, then this new one causes an overflow, //if we already have maxsprites, then this new one causes an overflow,
//set the flag and bail out. //set the flag and bail out.
if(oamcount == 8) { if(oamcount == maxsprites) {
PPU_status |= 0x20; PPU_status |= 0x20;
break; break;
} }
@ -1997,7 +1997,17 @@ int FCEUX_PPU_Loop(int skip) {
ppuphase = PPUPHASE_OBJ; ppuphase = PPUPHASE_OBJ;
//fetch sprite patterns //fetch sprite patterns
for(int s=0;s<8;s++) { for(int s=0;s<maxsprites;s++) {
//if we have hit our eight sprite pattern and we dont have any more sprites, then bail
if(s==oamcount && s>=8)
break;
//if this is a real sprite sprite, then it is not above the 8 sprite limit.
//this is how we support the no 8 sprite limit feature.
//not that at some point we may need a virtual CALL_PPUREAD which just peeks and doesnt increment any counters
//this could be handy for the debugging tools also
bool realSprite = (s<8);
uint8* oam = oams[scanslot][s]; uint8* oam = oams[scanslot][s];
uint32 line = yp - oam[0]; uint32 line = yp - oam[0];
@ -2023,7 +2033,7 @@ int FCEUX_PPU_Loop(int skip) {
patternAddress += line&7; patternAddress += line&7;
//garbage nametable fetches //garbage nametable fetches
runppu(kFetchTime); if(realSprite) runppu(kFetchTime);
if(((PPU[0]&0x38)!=0x18) && s == 2 && SpriteON ) { if(((PPU[0]&0x38)!=0x18) && s == 2 && SpriteON ) {
//(The MMC3 scanline counter is based entirely on PPU A12, triggered on rising edges (after the line remains low for a sufficiently long period of time)) //(The MMC3 scanline counter is based entirely on PPU A12, triggered on rising edges (after the line remains low for a sufficiently long period of time))
@ -2036,15 +2046,15 @@ int FCEUX_PPU_Loop(int skip) {
} }
} }
runppu(kFetchTime); if(realSprite) runppu(kFetchTime);
//pattern table fetches //pattern table fetches
RefreshAddr = patternAddress; RefreshAddr = patternAddress;
oam[4] = CALL_PPUREAD(RefreshAddr); oam[4] = CALL_PPUREAD(RefreshAddr);
runppu(kFetchTime); if(realSprite) runppu(kFetchTime);
RefreshAddr += 8; RefreshAddr += 8;
oam[5] = CALL_PPUREAD(RefreshAddr); oam[5] = CALL_PPUREAD(RefreshAddr);
runppu(kFetchTime); if(realSprite) runppu(kFetchTime);
//hflip //hflip