Skip to content

Commit

Permalink
small timing adjustments and ppu changes
Browse files Browse the repository at this point in the history
  • Loading branch information
@FIX94
FIX94 committed Feb 11, 2017
1 parent b751d05 commit 29430ce
Show file tree
Hide file tree
Showing 4 changed files with 151 additions and 95 deletions.
4 changes: 2 additions & 2 deletions apu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -249,11 +249,11 @@ void apuClockTimers()
dmcCurAddr = dmcAddr;
dmcCurLen = dmcLen;
//dmcCurVol = dmcVol;
if(!dmcSampleRemain)
//if(!dmcSampleRemain)
dmcCycle = 8;
dmcstart = false;
}
if(dmcFreqCtr > dmcFreq)
if(dmcFreqCtr >= dmcFreq)
{
dmcFreqCtr = 0;
dmcCycle++;
Expand Down
2 changes: 1 addition & 1 deletion main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@
#define DEBUG_KEY 0
#define DEBUG_LOAD_INFO 1

static const char *VERSION_STRING = "fixNES Alpha v0.5";
static const char *VERSION_STRING = "fixNES Alpha v0.5.1";

static void nesEmuDisplayFrame(void);
static void nesEmuMainLoop(void);
Expand Down
2 changes: 1 addition & 1 deletion mem.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,7 +65,7 @@ void memSet8(uint16_t addr, uint8_t val)
uint16_t dmaAddr = (val<<8);
//printf("ppuLoadOAM %04x\n", dmaAddr);
if(!fm2playRunning() || (fm2playRunning() && fm2playWaitDMAcycles()))
cpuIncWaitCycles(513);
cpuIncWaitCycles(514);
int i;
if(dmaAddr < 0x2000)
{
Expand Down
238 changes: 147 additions & 91 deletions ppu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
#define PPU_FLAG_NMI (1<<7)

//2001
#define PPU_GRAY (1<<0)
#define PPU_BG_8PX (1<<1)
#define PPU_SPRITE_8PX (1<<2)
#define PPU_BG_ENABLE (1<<3)
Expand Down Expand Up @@ -96,8 +97,12 @@ static uint8_t ppuOAMpos;
static uint8_t ppuOAM2pos;
static uint8_t ppuFineXScroll;
static uint8_t ppuSpriteTilePos;
static uint16_t ppuBGValA;
static uint16_t ppuBGValB;
static uint16_t ppuBGRegA;
static uint16_t ppuBGRegB;
static uint8_t ppuBGAttribValA;
static uint8_t ppuBGAttribValB;
static uint8_t ppuBGAttribRegA;
static uint8_t ppuBGAttribRegB;
static uint8_t ppuCurOverflowAdd;
Expand All @@ -112,6 +117,7 @@ static bool ppuSpriteSearch;
static bool ppuCurVBlankStat;
static bool ppuCurNMIStat;
static bool ppuOddFrame;
static bool ppuReadReg2;

extern bool nesPAL;

Expand Down Expand Up @@ -152,6 +158,7 @@ void ppuInit()
ppuCurVBlankStat = false;
ppuCurNMIStat = false;
ppuOddFrame = false;
ppuReadReg2 = false;
}

static uint16_t ppuGetVramTbl(uint16_t tblStart)
Expand Down Expand Up @@ -191,111 +198,149 @@ static uint16_t ppuGetVramTbl(uint16_t tblStart)
}
return tblStart;
}

static int ppuSprite0hit = 0;
bool ppuCycle()
{
ppuCurVBlankStat = !!(PPU_Reg[2] & PPU_FLAG_VBLANK);
ppuCurNMIStat = !!(PPU_Reg[0] & PPU_FLAG_NMI);

/* VBlank ends at first dot of the pre-render line */
/* Though results are better when clearing it a bit later */
if(curDot == 12 && curLine == ppuPreRenderLine)
{
#if PPU_DEBUG_VSYNC
printf("PPU End VBlank\n");
#endif
PPU_Reg[2] &= ~(PPU_FLAG_VBLANK | PPU_FLAG_SPRITEZERO | PPU_FLAG_OVERFLOW);
}
bool pictureOutput = (PPU_Reg[1] & (PPU_BG_ENABLE | PPU_SPRITE_ENABLE)) != 0;

/* Do Background Updates */
if(pictureOutput && (curLine == ppuPreRenderLine || curLine < VISIBLE_LINES))
if((curLine == ppuPreRenderLine || curLine < VISIBLE_LINES))
{
/* Update tile address if needed */
if((curDot <= VISIBLE_DOTS) && (curDot & 7) == 0)
{
if((ppuVramAddr & 0x1F) == 0x1F)
{
ppuVramAddr &= ~0x1F;
ppuVramAddr ^= 0x400;
}
else
ppuVramAddr++;
}
/* update Y position for writes */
if(curDot == VISIBLE_DOTS)
{
if(((ppuVramAddr>>12)&7) != 7)
ppuVramAddr += (1<<12);
else
{
ppuVramAddr &= ~0x7000;
uint8_t coarseY = (ppuVramAddr&0x3E0)>>5;
if(coarseY == 29)
{
coarseY = 0;
ppuVramAddr ^= 0x800;
}
else if(coarseY == 31)
coarseY = 0;
else
coarseY++;
ppuVramAddr &= ~0x3E0;
ppuVramAddr |= (coarseY<<5);
}
} /* Update horizontal values after scanline */
else if(curDot == VISIBLE_DOTS+1)
{
ppuVramAddr &= ~PPU_VRAM_HORIZONTAL_MASK;
ppuVramAddr |= (ppuTmpVramAddr & PPU_VRAM_HORIZONTAL_MASK);
}
/* Do BG Reg Updates */
if((curDot >= 319 || curDot <= VISIBLE_DOTS) && (curDot & 7) == 0)
if((curDot >= 319 || (curDot && curDot <= VISIBLE_DOTS)) && (curDot & 7) == 0)
{
uint16_t cPpuTbl = ppuGetVramTbl(ppuVramAddr & 0xC00);
/* Select new BG Tiles */
uint16_t chrROMBG = (PPU_Reg[0] & PPU_BACKGROUND_ADDR) ? 0x1000 : 0;
uint16_t workAddr = cPpuTbl | (ppuVramAddr & 0x3FF);
uint8_t curBGtile = PPU_VRAM[workAddr];
uint8_t curTileY = (ppuVramAddr>>12)&7;
uint16_t curBGTile = chrROMBG+(curBGtile<<4)+curTileY;
/* Select new BG Background Attribute */
uint8_t cAttrib = ((ppuVramAddr>>4)&0x38) | ((ppuVramAddr>>2)&7);
uint16_t attributeAddr = cPpuTbl | (0x3C0 | cAttrib);
uint8_t cPalByte = PPU_VRAM[attributeAddr];
/* Update BG Tile Regs */
ppuBGRegA >>= 8;
ppuBGRegB >>= 8;
ppuBGRegA |= mapperChrGet8(curBGTile)<<8;
ppuBGRegB |= mapperChrGet8(curBGTile+8)<<8;
/* Update BG Background Attribute Regs */
ppuBGAttribRegA = ppuBGAttribRegB;
uint8_t coarseX = (ppuVramAddr & 0x1F);
uint8_t coarseY = ((ppuVramAddr & 0x3E0)>>5);
bool left = ((coarseX&2) == 0);
bool top = ((coarseY&2) == 0);
if(top)
{
if(left)
ppuBGAttribRegB = (cPalByte&3)<<2;
{
ppuBGAttribValA = (cPalByte)&1;
ppuBGAttribValB = (cPalByte>>1)&1;
}
else
ppuBGAttribRegB = (cPalByte&12);
{
ppuBGAttribValA = (cPalByte>>2)&1;
ppuBGAttribValB = (cPalByte>>3)&1;
}
}
else
{
if(left)
ppuBGAttribRegB = (cPalByte&48)>>2;
{
ppuBGAttribValA = (cPalByte>>4)&1;
ppuBGAttribValB = (cPalByte>>5)&1;
}
else
ppuBGAttribRegB = (cPalByte&192)>>4;
{
ppuBGAttribValA = (cPalByte>>6)&1;
ppuBGAttribValB = (cPalByte>>7)&1;
}
}
if(curDot == 328)
{
int i;
for(i = 0; i < 8; i++)
{
ppuBGAttribRegA <<= 1;
ppuBGAttribRegB <<= 1;
ppuBGAttribRegA |= ppuBGAttribValA;
ppuBGAttribRegB |= ppuBGAttribValB;
}
}
}
if(pictureOutput)
{
/* Update tile address if needed */
if((curDot >= 328 || (curDot >= 8 && curDot <= VISIBLE_DOTS)) && (curDot & 7) == 0)
{
if((ppuVramAddr & 0x1F) == 0x1F)
{
ppuVramAddr &= ~0x1F;
ppuVramAddr ^= 0x400;
}
else
ppuVramAddr++;
}
/* update Y position for writes */
if(curDot == VISIBLE_DOTS)
{
if(((ppuVramAddr>>12)&7) != 7)
ppuVramAddr += (1<<12);
else
{
ppuVramAddr &= ~0x7000;
uint8_t coarseY = (ppuVramAddr&0x3E0)>>5;
if(coarseY == 29)
{
coarseY = 0;
ppuVramAddr ^= 0x800;
}
else if(coarseY == 31)
coarseY = 0;
else
coarseY++;
ppuVramAddr &= ~0x3E0;
ppuVramAddr |= (coarseY<<5);
}
} /* Update horizontal values after scanline */
else if(curDot == VISIBLE_DOTS+1)
{
ppuVramAddr &= ~PPU_VRAM_HORIZONTAL_MASK;
ppuVramAddr |= (ppuTmpVramAddr & PPU_VRAM_HORIZONTAL_MASK);
}
}
/* Do BG Reg Updates */
if((curDot >= 319 || curDot <= VISIBLE_DOTS) && (curDot & 7) == 4)
{
uint16_t cPpuTbl = ppuGetVramTbl(ppuVramAddr & 0xC00);
/* Select new BG Tiles */
uint16_t chrROMBG = (PPU_Reg[0] & PPU_BACKGROUND_ADDR) ? 0x1000 : 0;
uint16_t workAddr = cPpuTbl | (ppuVramAddr & 0x3FF);
uint8_t curBGtileReg = PPU_VRAM[workAddr];
uint8_t curTileY = (ppuVramAddr>>12)&7;
uint16_t curBGTile = chrROMBG+(curBGtileReg<<4)+curTileY;
ppuBGValA = mapperChrGet8(curBGTile);
ppuBGValB = mapperChrGet8(curBGTile+8);
}
if(curDot >= 8 && curDot <= VISIBLE_DOTS && ((curDot&7) == 0))
{
ppuBGRegA |= ppuBGValA;
ppuBGRegB |= ppuBGValB;
}
else if(curDot == 328)
{
ppuBGRegA = ppuBGValA<<8;
ppuBGRegB = ppuBGValB<<8;
}
else if(curDot == 336)
{
ppuBGRegA |= ppuBGValA;
ppuBGRegB |= ppuBGValB;
}
}

/* Only render visible dots after pre-render line and before post-render line */
if(curDot < VISIBLE_DOTS && curLine < VISIBLE_LINES)
{
/* Grab color to render from BG and Sprites */
uint8_t curCol = ppuDoBackground(0, curDot);
ppuBGRegA <<= 1;
ppuBGRegB <<= 1;
ppuBGAttribRegA <<= 1;
ppuBGAttribRegB <<= 1;
ppuBGAttribRegA |= ppuBGAttribValA;
ppuBGAttribRegB |= ppuBGAttribValB;
curCol = ppuDoSprites(curCol, curDot);
if((curCol&3) == 0) //0,4,8 and C wrap
curCol &= ~0x10; //down to 0x00
Expand All @@ -307,9 +352,9 @@ bool ppuCycle()
curCol = 0xFF;
/* Draw current dot on screen */
size_t drawPos = (curDot<<2)+(curLine<<10);
if(curCol != 0xFF && pictureOutput)
if(curCol != 0xFF)
{
uint8_t cPalIdx = (PPU_PALRAM[curCol]&0x3F)*3;
uint8_t cPalIdx = (PPU_PALRAM[curCol]&((PPU_Reg[1]&PPU_GRAY)?0x30:0x3F))*3;
textureImage[drawPos] = PPU_Pal[cPalIdx+2];
textureImage[drawPos+1] = PPU_Pal[cPalIdx+1];
textureImage[drawPos+2] = PPU_Pal[cPalIdx];
Expand Down Expand Up @@ -432,16 +477,34 @@ bool ppuCycle()
ppuOAM2pos = 0;
//printf("Line done\n");
}
if(ppuSprite0hit == 1)
{
PPU_Reg[2] |= PPU_FLAG_SPRITEZERO;
ppuSprite0hit = 0;
}
else if(ppuSprite0hit > 1)
ppuSprite0hit--;
/* VBlank start at first dot after post-render line */
/* Though results are better when starting it a bit later */
if(curDot == 12 && curLine == 241)
if(curDot == 8 && curLine == 241)
{
ppuNMITriggered = false;
PPU_Reg[2] |= PPU_FLAG_VBLANK;
if(!ppuReadReg2)
PPU_Reg[2] |= PPU_FLAG_VBLANK;
#if PPU_DEBUG_VSYNC
printf("PPU Start VBlank\n");
#endif
}
ppuReadReg2 = false;
/* VBlank ends at first dot of the pre-render line */
/* Though results are better when clearing it a bit later */
if(curDot == 8 && curLine == ppuPreRenderLine)
{
#if PPU_DEBUG_VSYNC
printf("PPU End VBlank\n");
#endif
PPU_Reg[2] &= ~(PPU_FLAG_VBLANK | PPU_FLAG_SPRITEZERO | PPU_FLAG_OVERFLOW);
}
/* Wrap back down after pre-render line */
if(curLine == ppuLinesTotal)
{
Expand All @@ -457,24 +520,16 @@ static uint8_t ppuDoBackground(uint8_t color, uint8_t dot)
if((dot < 8 && !(PPU_Reg[1] & PPU_BG_8PX)) || !(PPU_Reg[1] & PPU_BG_ENABLE))
return color;

uint8_t curTileX = (dot+ppuFineXScroll)&7;
if((dot&7)+ppuFineXScroll <= 7)
if(ppuBGRegA & (0x80>>ppuFineXScroll<<8))
color |= 1;
if(ppuBGRegB & (0x80>>ppuFineXScroll<<8))
color |= 2;
if(color != 0)
{
if(ppuBGRegA & (0x80>>curTileX))
color |= 1;
if(ppuBGRegB & (0x80>>curTileX))
color |= 2;
if(color != 0)
color |= ppuBGAttribRegA;
}
else
{
if(ppuBGRegA & (0x8000>>curTileX))
color |= 1;
if(ppuBGRegB & (0x8000>>curTileX))
color |= 2;
if(color != 0)
color |= ppuBGAttribRegB;
if(ppuBGAttribRegA & 0x80>>ppuFineXScroll)
color |= 4;
if(ppuBGAttribRegB & 0x80>>ppuFineXScroll)
color |= 8;
}

#if PPU_DEBUG_ULTRA
Expand Down Expand Up @@ -504,9 +559,9 @@ static uint8_t ppuDoSprites(uint8_t color, uint8_t dot)
sprCol |= 1;
if(PPU_Sprites[i+1] & (0x80>>cSpriteX))
sprCol |= 2;
if(i == 0 && ppuHasZSprite && dot < 255 && ((color&3) != 0) && (sprCol != 0) && !(PPU_Reg[2] & PPU_FLAG_SPRITEZERO))
if(i == 0 && ppuHasZSprite && dot < 255 && ((color&3) != 0) && (sprCol != 0) && !(PPU_Reg[2] & PPU_FLAG_SPRITEZERO) && !ppuSprite0hit)
{
PPU_Reg[2] |= PPU_FLAG_SPRITEZERO;
ppuSprite0hit = 5;
#if PPU_DEBUG_ULTRA
printf("Zero sprite hit at x %i y %i cSpriteDot %i "
"table %04x color %02x sprCol %02x\n", dot, curLine, cSpriteDot, ppuGetVramTbl((PPU_Reg[0]&3)<<10), color, sprCol);
Expand Down Expand Up @@ -649,6 +704,7 @@ uint8_t ppuGet8(uint8_t reg)
ret = PPU_Reg[reg];
PPU_Reg[reg] &= ~PPU_FLAG_VBLANK;
ppuTmpWrite = false;
ppuReadReg2 = true;
}
else if(reg == 4)
ret = PPU_OAM[ppuOAMpos];
Expand All @@ -672,7 +728,7 @@ uint8_t ppuGet8(uint8_t reg)
uint8_t palRamAddr = (writeAddr&0x1F);
if((palRamAddr&3) == 0)
palRamAddr &= ~0x10;
ret = PPU_PALRAM[palRamAddr];
ret = PPU_PALRAM[palRamAddr]&((PPU_Reg[1]&PPU_GRAY)?0x30:0x3F);
//shadow read
uint16_t workAddr = ppuGetVramTbl(writeAddr) | (writeAddr & 0x3FF);
ppuVramReadBuf = PPU_VRAM[workAddr];
Expand Down

0 comments on commit 29430ce

Please sign in to comment.