public PPU(Engine engine)
{
this.Engine = engine;
this.dumpSprite = new SpriteDumpFunc(dumpSpriteSmall);
// Attribute Lookup Tables
for (int i = 0; i != 0x400; ++i)
{
AttributeShiftTable[i] = (byte)(((i >> 4) & 0x04) | (i & 0x02));
AttributeLocationTable[i] = (byte)(((i >> 4) & 0x38) | ((i >> 2)) & 7);
}
// Setup nametables
Nametables.SetupNametables(this.Mirroring);
}
public void Run(int cpuCycles)
{
int ppuCycles = (int)((decimal)(cpuCycles + CycleCarry) * CPUScaling); // Number of ppu cycles to do
int endCycle = 341; // 0-340 cycles inclusive for 341 cycles total.
// Timing!
for (int i = 0; i < ppuCycles; ++i)
{
// if ((Cycle == 0) && (CurrentScaline == 0))
// Flags.Loopy_V = (ushort)(0x2000 | (Flags.NameTableAddress << 10));
++Cycle;
if (Cycle == 256) // Significance?
{
// Todo: handle short scanlines, see nes_emu.txt
endCycle = 341;
}
else if (Cycle == 304)
{
//frame start, $2006 gets reloaded with the tmp addr
//this happens in the dummy scanline, and the PPU
//is rendering. The reason for the reload because
//Loopy_V is changed as the PPU is rendering.
//Loopy_V is the "program counter" for the PPU.
if ((CurrentScaline < 0) && Rendering)
{
Flags.Loopy_V = Flags.Loopy_T;
}
}
else if (Cycle == endCycle)
{
++CurrentScaline;
Cycle = 0;
// Start of VBlank (240 is idle)
if (CurrentScaline == 241)
{
//dumpNametable();
//dumpSprites();
Engine.Graphics.Render();
Flags.Status |= 0x80; // Set VBlank flag in $2002
Engine.CPU.NMI = ((Flags.Control1 & 0x80) > 1) ? true : false; // Only trigger NMI if they want us to in $2000
Flags.SprAddr = 0; // Gets reset at end of frame
Engine.CPU.Flags.InterruptDisable = true; // Set NMI
Engine.CPU.SinceLastVBlank = 0;
}
else if (CurrentScaline == EndScanline)
{
CurrentScaline = -1;
CurrentSprite = 0;
if (Flags.TallSprites)
{
dumpSprite = new SpriteDumpFunc(dumpSpriteTall);
}
else
{
dumpSprite = new SpriteDumpFunc(dumpSpriteSmall);
}
// todo: this.Rendering, and short scanlines
}
}
else if ((CurrentScaline < 0) && (Cycle == 1))
{
// VBlank gets cleared at cycle 1 of scanline -1
Flags.Status = 0; // ALL 0?!
}
// Sprites!
if ((CurrentSprite < 32) && (CurrentScaline > 0))
{
dumpSprite(CurrentSprite * 4);
CurrentSprite++;
}
// :D
if ((CurrentScaline < 240) && (CurrentScaline > 0))
{
// Datas!
switch (Cycle)
{
// Cycle 0 - Get tile
// Cycle 1 - Gets the pattern address for the tile
// Cycle 2 - Gets attribute addr[/shift]
// Cycle 3 - Apply attribute
// Cycle 4 - Nothing
// Cycle 5 - Get lower bit from nt [We do upper too]
// Cycle 6 - Get pattern address for upper two bits [We don't need this]
// Cycle 7 - Get upper bit from nt [Did this in Cycle 5]
// Rinse and repeat.
// Buuut we're not gonna do that -- Just make sure we update Loopy_V at cycle 251
// Cycle 0 - We'll do all of the above! :)
case 0:
case 8:
case 16:
case 24:
case 32:
case 40:
case 48:
case 56:
case 64:
case 72:
case 80:
case 88:
case 96:
case 104:
case 112:
case 120:
case 128:
case 136:
case 144:
case 152:
case 160:
case 168:
case 176:
case 184:
case 192:
case 200:
case 208:
case 216:
case 224:
case 232:
case 240:
case 248:
// Find out which pattern to use
byte tile = Nametables[Flags.Loopy_V];
int pattern_addr = (tile << 6) | (Flags.BGTable << 14);
// Get attribute
int attribute_addr = 0x23C0 | (Flags.Loopy_V & 0xC00) | (AttributeLocationTable[Flags.Loopy_V & 0x3FF]);
int attribute_shift = AttributeShiftTable[Flags.Loopy_V & 0x3FF];
int attribute = ((Nametables[attribute_addr] >> attribute_shift) & 3) << 2; // Remember attribute is upper 2 bits of color.
// Now we have the pattern_addr and the attribute, we can render! :)
int x = Flags.Loopy_V & 31; // bits 0-4 are x-scroll
int y = (Flags.Loopy_V & 0x3E0) >> 5; // bits 5-9 are y-scroll.
y = (y > 29) ? 29 : y;
Engine.Graphics.DrawTile(Engine.Cartridge.CHRBanks[0], Engine.Graphics.BGBuffer, 0, (256 * Flags.BGTable) + tile, x * 8, y * 8, attribute);
break;
case 3:
case 11:
case 19:
case 27:
case 35:
case 43:
case 51:
case 59:
case 67:
case 75:
case 83:
case 91:
case 99:
case 107:
case 115:
case 123:
case 131:
case 139:
case 147:
case 155:
case 163:
case 171:
case 179:
case 187:
case 195:
case 203:
case 211:
case 219:
case 227:
case 235:
case 243:
if ((Flags.Loopy_V & 0x1F) == 0x1F)
{
Flags.Loopy_V ^= 0x41F;
}
else
{
++Flags.Loopy_V;
}
break;
case 323:
case 331:
if ((Flags.Loopy_V & 0x1F) == 0x1F)
{
Flags.Loopy_V ^= 0x41F;
}
else
{
++Flags.Loopy_V;
}
break;
case 251:
if ((Flags.Loopy_V & 0x1F) == 0x1F)
{
Flags.Loopy_V ^= 0x41F;
}
else
{
++Flags.Loopy_V;
}
if ((Flags.Loopy_V & 0x7000) == 0x7000)
{
int tmp = Flags.Loopy_V & 0x3E0;
//reset tile y offset 12 - 14 in addr
Flags.Loopy_V &= 0xFFF;
switch (tmp)
{
//29, flip bit 11
case 0x3A0:
Flags.Loopy_V ^= 0xBA0;
break;
case 0x3E0: //31, back to 0
Flags.Loopy_V ^= 0x3E0;
break;
default: //inc y scroll if not reached
Flags.Loopy_V += 0x20;
break;
}
}
else //inc fine y
{
Flags.Loopy_V += 0x1000;
}
break;
}
}
}
}
public void Run(int cpuCycles)
{
int ppuCycles = (int)((decimal)(cpuCycles + CycleCarry) * CPUScaling); // Number of ppu cycles to do
int endCycle = 341; // 0-340 cycles inclusive for 341 cycles total.
// Timing!
for (int i = 0; i < ppuCycles; ++i)
{
// if ((Cycle == 0) && (CurrentScaline == 0))
// Flags.Loopy_V = (ushort)(0x2000 | (Flags.NameTableAddress << 10));
++Cycle;
if (Cycle == 256) // Significance?
{
// Todo: handle short scanlines, see nes_emu.txt
endCycle = 341;
} else if (Cycle == 304)
{
//frame start, $2006 gets reloaded with the tmp addr
//this happens in the dummy scanline, and the PPU
//is rendering. The reason for the reload because
//Loopy_V is changed as the PPU is rendering.
//Loopy_V is the "program counter" for the PPU.
if ((CurrentScaline < 0) && Rendering)
Flags.Loopy_V = Flags.Loopy_T;
} else if (Cycle == endCycle)
{
++CurrentScaline;
Cycle = 0;
// Start of VBlank (240 is idle)
if (CurrentScaline == 241)
{
//dumpNametable();
//dumpSprites();
Engine.Graphics.Render();
Flags.Status |= 0x80; // Set VBlank flag in $2002
Engine.CPU.NMI = ((Flags.Control1 & 0x80) > 1) ? true : false; // Only trigger NMI if they want us to in $2000
Flags.SprAddr = 0; // Gets reset at end of frame
Engine.CPU.Flags.InterruptDisable = true; // Set NMI
Engine.CPU.SinceLastVBlank = 0;
} else if (CurrentScaline == EndScanline)
{
CurrentScaline = -1;
CurrentSprite = 0;
if (Flags.TallSprites)
dumpSprite = new SpriteDumpFunc(dumpSpriteTall);
else
dumpSprite = new SpriteDumpFunc(dumpSpriteSmall);
// todo: this.Rendering, and short scanlines
}
} else if ((CurrentScaline < 0) && (Cycle == 1))
{
// VBlank gets cleared at cycle 1 of scanline -1
Flags.Status = 0; // ALL 0?!
}
// Sprites!
if ((CurrentSprite < 32) && (CurrentScaline > 0))
{
dumpSprite(CurrentSprite * 4);
CurrentSprite++;
}
// :D
if ((CurrentScaline < 240) && (CurrentScaline > 0))
{
// Datas!
switch(Cycle)
{
// Cycle 0 - Get tile
// Cycle 1 - Gets the pattern address for the tile
// Cycle 2 - Gets attribute addr[/shift]
// Cycle 3 - Apply attribute
// Cycle 4 - Nothing
// Cycle 5 - Get lower bit from nt [We do upper too]
// Cycle 6 - Get pattern address for upper two bits [We don't need this]
// Cycle 7 - Get upper bit from nt [Did this in Cycle 5]
// Rinse and repeat.
// Buuut we're not gonna do that -- Just make sure we update Loopy_V at cycle 251
// Cycle 0 - We'll do all of the above! :)
case 0: case 8: case 16: case 24:
case 32: case 40: case 48: case 56:
case 64: case 72: case 80: case 88:
case 96: case 104: case 112: case 120:
case 128: case 136: case 144: case 152:
case 160: case 168: case 176: case 184:
case 192: case 200: case 208: case 216:
case 224: case 232: case 240: case 248:
// Find out which pattern to use
byte tile = Nametables[Flags.Loopy_V];
int pattern_addr = (tile << 6) | (Flags.BGTable << 14);
// Get attribute
int attribute_addr = 0x23C0 | (Flags.Loopy_V & 0xC00) | (AttributeLocationTable[Flags.Loopy_V & 0x3FF]);
int attribute_shift = AttributeShiftTable[Flags.Loopy_V & 0x3FF];
int attribute = ((Nametables[attribute_addr] >> attribute_shift) & 3) << 2; // Remember attribute is upper 2 bits of color.
// Now we have the pattern_addr and the attribute, we can render! :)
int x = Flags.Loopy_V & 31; // bits 0-4 are x-scroll
int y = (Flags.Loopy_V & 0x3E0) >> 5; // bits 5-9 are y-scroll.
y = (y > 29) ? 29 : y;
Engine.Graphics.DrawTile(Engine.Cartridge.CHRBanks[0], Engine.Graphics.BGBuffer, 0, (256 * Flags.BGTable) + tile, x*8, y*8, attribute);
break;
case 3: case 11: case 19: case 27:
case 35: case 43: case 51: case 59:
case 67: case 75: case 83: case 91:
case 99: case 107: case 115: case 123:
case 131: case 139: case 147: case 155:
case 163: case 171: case 179: case 187:
case 195: case 203: case 211: case 219:
case 227: case 235: case 243:
if ((Flags.Loopy_V & 0x1F) == 0x1F)
Flags.Loopy_V ^= 0x41F;
else
++Flags.Loopy_V;
break;
case 323: case 331:
if ((Flags.Loopy_V & 0x1F) == 0x1F)
Flags.Loopy_V ^= 0x41F;
else
++Flags.Loopy_V;
break;
case 251:
if ((Flags.Loopy_V & 0x1F) == 0x1F)
Flags.Loopy_V ^= 0x41F;
else
++Flags.Loopy_V;
if ((Flags.Loopy_V & 0x7000) == 0x7000)
{
int tmp = Flags.Loopy_V & 0x3E0;
//reset tile y offset 12 - 14 in addr
Flags.Loopy_V &= 0xFFF;
switch (tmp)
{
//29, flip bit 11
case 0x3A0:
Flags.Loopy_V ^= 0xBA0;
break;
case 0x3E0: //31, back to 0
Flags.Loopy_V ^= 0x3E0;
break;
default: //inc y scroll if not reached
Flags.Loopy_V += 0x20;
break;
}
}
else //inc fine y
Flags.Loopy_V += 0x1000;
break;
}
}
}
}
