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PPU: Removed existing sprite 0 timing patch - replaced with a better solution that fixes ppu_sprite_overflow/03-timing and ppu_sprite_hit/09-timing.

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(Confirmed this old patch is no longer needed for Dizzy & Micro Machines)
This commit is contained in:
Souryo 2016-05-18 20:46:03 -04:00
parent 4de5827a4e
commit d0cc79aeed
2 changed files with 5 additions and 21 deletions
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25
Core/PPU.cpp
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@ -36,7 +36,6 @@ PPU::~PPU()
void PPU::Reset()
{
_sprite0HitCycle = -1;
_prevRenderingEnabled = false;
_renderingEnabled = false;
@ -267,8 +266,6 @@ void PPU::WriteRAM(uint16_t addr, uint8_t value)
UpdateVideoRamAddr();
break;
case PPURegisters::SpriteDMA:
//_spriteDmaAddr & _spriteDmaCounter are probably not the correct solution for this
//Missing something else in the PPU/CPU DMA logic maybe?
_spriteDmaCounter = 0x100;
_spriteDmaAddr = _state.SpriteRamAddr;
CPU::RunDMATransfer(_spriteRAM, value);
@ -352,11 +349,6 @@ void PPU::SetMaskRegister(uint8_t value)
void PPU::UpdateStatusFlag()
{
if(_sprite0HitCycle >= 0 && _sprite0HitCycle < (int32_t)_cycle) {
_statusFlags.Sprite0Hit = true;
_sprite0HitCycle = -1;
}
_state.Status = ((uint8_t)_statusFlags.SpriteOverflow << 5) |
((uint8_t)_statusFlags.Sprite0Hit << 6) |
((uint8_t)_statusFlags.VerticalBlank << 7);
@ -577,15 +569,12 @@ uint32_t PPU::GetPixelColor(uint32_t &paletteOffset)
if(spriteColor != 0) {
//First sprite without a 00 color, use it.
if(i == 0 && backgroundColor != 0 && _sprite0Visible && _cycle != 256 && _flags.BackgroundEnabled && !_statusFlags.Sprite0Hit && _sprite0HitCycle == -1) {
if(i == 0 && backgroundColor != 0 && _sprite0Visible && _cycle != 256 && _flags.BackgroundEnabled && !_statusFlags.Sprite0Hit) {
//"The hit condition is basically sprite zero is in range AND the first sprite output unit is outputting a non-zero pixel AND the background drawing unit is outputting a non-zero pixel."
//"Sprite zero hits do not register at x=255" (cycle 256)
//"... provided that background and sprite rendering are both enabled"
//"Should always miss when Y >= 239"
//"Sprite zero hits act as if the image starts at cycle 2 (which is the same cycle that the shifters shift for the first time), so the sprite zero flag will be raised at this point at the earliest."
//Need to set the sprite 0 flag on the next PPU clock
_sprite0HitCycle = (int32_t)_cycle;
_statusFlags.Sprite0Hit = true;
}
if(backgroundColor == 0 || !_spriteTiles[i].BackgroundPriority) {
@ -668,9 +657,10 @@ void PPU::ProcessPrerenderScanline()
memcpy(_spriteRAM, _spriteRAM + (_state.SpriteRamAddr & 0xF8), 8);
}
if(_cycle == 1) {
if(_cycle == 0) {
_statusFlags.SpriteOverflow = false;
_statusFlags.Sprite0Hit = false;
} else if(_cycle == 1) {
_statusFlags.VerticalBlank = false;
}
@ -705,11 +695,6 @@ void PPU::ProcessVisibleScanline()
}
} else if(_cycle >= 321 && _cycle <= 336) {
LoadTileInfo();
} else if(_cycle == 340 && _sprite0HitCycle >= 0) {
//Set sprite 0 hit flag at the end of the scanline if the cycle count was set.
//This is just a way of not checking & setting the flag every cycle since the flag needs to be set with a 1 cycle delay
_statusFlags.Sprite0Hit = true;
_sprite0HitCycle = -1;
}
ProcessPreVBlankScanline();
@ -962,7 +947,7 @@ void PPU::StreamState(bool saving)
Stream<uint8_t>(_oamCopybuffer);
Stream<bool>(_spriteInRange);
Stream<bool>(_sprite0Added);
Stream<int32_t>(_sprite0HitCycle);
Stream<int32_t>();
Stream<uint8_t>(_spriteAddrH);
Stream<uint8_t>(_spriteAddrL);
Stream<bool>(_oamCopyDone);

1
Core/PPU.h
View file

@ -142,7 +142,6 @@ class PPU : public IMemoryHandler, public Snapshotable
uint8_t _oamCopybuffer;
bool _spriteInRange;
bool _sprite0Added;
int32_t _sprite0HitCycle;
uint8_t _spriteAddrH;
uint8_t _spriteAddrL;
bool _oamCopyDone;