Misc: Added "Remove sprite limit" option

Core/EmulationSettings.h

@@ -9,6 +9,7 @@ enum EmulationFlags
 	ShowFPS = 0x02,
 	VerticalSync = 0x04,
 	AllowInvalidInput = 0x08,
+	RemoveSpriteLimit = 0x10,
 
 	Mmc3IrqAltBehavior = 0x8000,
 };

Core/PPU.cpp

@@ -439,13 +439,8 @@ void PPU::LoadTileInfo()
 	}
 }
 
-void PPU::LoadSpriteTileInfo()
+void PPU::LoadSprite(uint8_t spriteY, uint8_t tileIndex, uint8_t attributes, uint8_t spriteX, bool extraSprite)
 {
-	uint32_t spriteAddr = _spriteIndex * 4;
-	uint8_t spriteY = _secondarySpriteRAM[spriteAddr];
-	uint8_t tileIndex = _secondarySpriteRAM[spriteAddr + 1];
-	uint8_t attributes = _secondarySpriteRAM[spriteAddr + 2];
-	uint8_t spriteX = _secondarySpriteRAM[spriteAddr + 3];
 	bool backgroundPriority = (attributes & 0x20) == 0x20;
 	bool horizontalMirror = (attributes & 0x40) == 0x40;
 	bool verticalMirror = (attributes & 0x80) == 0x80;
@@ -464,17 +459,23 @@ void PPU::LoadSpriteTileInfo()
 		tileAddr = ((tileIndex << 4) | _flags.SpritePatternAddr) + lineOffset;
 	}
 
-	if(_spriteIndex < _spriteCount && spriteY < 240) {
+	if((_spriteIndex < _spriteCount || extraSprite) && spriteY < 240) {
 		_spriteTiles[_spriteIndex].BackgroundPriority = backgroundPriority;
 		_spriteTiles[_spriteIndex].HorizontalMirror = horizontalMirror;
 		_spriteTiles[_spriteIndex].VerticalMirror = verticalMirror;
 		_spriteTiles[_spriteIndex].PaletteOffset = ((attributes & 0x03) << 2) | 0x10;
-		_spriteTiles[_spriteIndex].LowByte = _memoryManager->ReadVRAM(tileAddr);
+		if(extraSprite) {
-		_spriteTiles[_spriteIndex].HighByte = _memoryManager->ReadVRAM(tileAddr + 8);
+			//Use DebugReadVRAM for extra sprites to prevent most side-effects.
+			_spriteTiles[_spriteIndex].LowByte = _memoryManager->DebugReadVRAM(tileAddr);
+			_spriteTiles[_spriteIndex].HighByte = _memoryManager->DebugReadVRAM(tileAddr + 8);
+		} else {
+			_spriteTiles[_spriteIndex].LowByte = _memoryManager->ReadVRAM(tileAddr);
+			_spriteTiles[_spriteIndex].HighByte = _memoryManager->ReadVRAM(tileAddr + 8);
+		}
 		_spriteTiles[_spriteIndex].TileAddr = tileAddr;
 		_spriteTiles[_spriteIndex].OffsetY = lineOffset;
 		_spriteTiles[_spriteIndex].SpriteX = spriteX;
-	} else {
+	} else if(!extraSprite) {
 		//Fetches to sprite 0xFF for remaining sprites/hidden - used by MMC3 IRQ counter
 		lineOffset = 0;
 		tileIndex = 0xFF;
@@ -491,6 +492,25 @@ void PPU::LoadSpriteTileInfo()
 	_spriteIndex++;
 }
 
+void PPU::LoadExtraSprites()
+{
+	if(_spriteCount == 8 && EmulationSettings::CheckFlag(EmulationFlags::RemoveSpriteLimit)) {
+		for(uint32_t i = _overflowSpriteAddr; i < 0x100; i += 4) {
+			uint8_t spriteY = _spriteRAM[i];
+			if(_scanline >= spriteY && _scanline < spriteY + (_flags.LargeSprites ? 16 : 8)) {
+				LoadSprite(spriteY, _spriteRAM[i + 1], _spriteRAM[i + 2], _spriteRAM[i + 3], true);
+				_spriteCount++;
+			}
+		}
+	}
+}
+
+void PPU::LoadSpriteTileInfo()
+{
+	uint8_t *spriteAddr = _secondarySpriteRAM + _spriteIndex * 4;
+	LoadSprite(*spriteAddr, *(spriteAddr+1), *(spriteAddr+2), *(spriteAddr+3), false);
+}
+
 void PPU::LoadNextTile()
 {
 	_state.LowBitShift |= _nextTile.LowByte;
@@ -677,6 +697,7 @@ void PPU::CopyOAMData()
 			_sprite0Added = false;
 			_spriteInRange = false;
 			_secondaryOAMAddr = 0;
+			_overflowSpriteAddr = 0;
 
 			_oamCopyDone = false;
 			_spriteAddrH = (_state.SpriteRamAddr >> 2) & 0x3F;
@@ -684,6 +705,8 @@ void PPU::CopyOAMData()
 		} else if(_cycle == 256) {
 			_sprite0Visible = _sprite0Added;
 			_spriteCount = (_secondaryOAMAddr >> 2);
+
+			LoadExtraSprites();
 		}
 
 		if(_cycle & 0x01) {
@@ -727,6 +750,11 @@ void PPU::CopyOAMData()
 					}
 				} else {
 					//8 sprites have been found, check next sprite for overflow + emulate PPU bug
+					if(_overflowSpriteAddr == 0) {
+						//Used to remove sprite limit
+						_overflowSpriteAddr = _spriteAddrH * 4;
+					}
+
 					if(_spriteInRange) {
 						//Sprite is visible, consider this to be an overflow
 						_statusFlags.SpriteOverflow = true;
@@ -878,7 +906,7 @@ void PPU::StreamState(bool saving)
 	Stream<uint8_t>(_previousTile.HighByte);
 	Stream<uint32_t>(_previousTile.PaletteOffset);
 
-	for(int i = 0; i < 8; i++) {
+	for(int i = 0; i < 64; i++) {
 		Stream<uint8_t>(_spriteTiles[i].SpriteX);
 		Stream<uint8_t>(_spriteTiles[i].LowByte);
 		Stream<uint8_t>(_spriteTiles[i].HighByte);

Core/PPU.h

@@ -123,11 +123,12 @@ class PPU : public IMemoryHandler, public Snapshotable
 		TileInfo _nextTile;
 		TileInfo _previousTile;
 
-		SpriteInfo _spriteTiles[8];
+		SpriteInfo _spriteTiles[64];
 		uint32_t _spriteCount = 0;
 		uint32_t _secondaryOAMAddr = 0;
 		bool _sprite0Visible = false;
 
+		uint32_t _overflowSpriteAddr = 0;
 		uint32_t _spriteIndex = 0;
 
 		uint8_t _openBus = 0;
@@ -178,7 +179,9 @@ class PPU : public IMemoryHandler, public Snapshotable
 		void WritePaletteRAM(uint16_t addr, uint8_t value);
 
 		void LoadTileInfo();
+		void LoadSprite(uint8_t spriteY, uint8_t tileIndex, uint8_t attributes, uint8_t spriteX, bool extraSprite);
 		void LoadSpriteTileInfo();
+		void LoadExtraSprites();
 		void ShiftTileRegisters();
 		void InitializeShiftRegisters();
 		void LoadNextTile();

GUI.NET/Config/PreferenceInfo.cs

@@ -17,6 +17,7 @@ namespace Mesen.GUI.Config
 		public bool AutoLoadIpsPatches = true;
 		public bool AssociateNesFiles = false;
 		public bool AllowInvalidInput = false;
+		public bool RemoveSpriteLimit = false;
 
 		public bool UseAlternativeMmc3Irq = false;
 
@@ -40,6 +41,7 @@ namespace Mesen.GUI.Config
 
 			InteropEmu.SetFlag(EmulationFlags.Mmc3IrqAltBehavior, preferenceInfo.UseAlternativeMmc3Irq);
 			InteropEmu.SetFlag(EmulationFlags.AllowInvalidInput, preferenceInfo.AllowInvalidInput);
+			InteropEmu.SetFlag(EmulationFlags.RemoveSpriteLimit, preferenceInfo.RemoveSpriteLimit);
 		}
 	}
 }

GUI.NET/Forms/Config/frmPreferences.Designer.cs

@@ -47,6 +47,7 @@
 			this.tableLayoutPanel1 = new System.Windows.Forms.TableLayoutPanel();
 			this.chkUseAlternativeMmc3Irq = new System.Windows.Forms.CheckBox();
 			this.chkAllowInvalidInput = new System.Windows.Forms.CheckBox();
+			this.chkRemoveSpriteLimit = new System.Windows.Forms.CheckBox();
 			this.tlpMain.SuspendLayout();
 			this.flowLayoutPanel6.SuspendLayout();
 			this.tabMain.SuspendLayout();
@@ -273,10 +274,13 @@
 			this.tableLayoutPanel1.ColumnStyles.Add(new System.Windows.Forms.ColumnStyle(System.Windows.Forms.SizeType.Percent, 100F));
 			this.tableLayoutPanel1.Controls.Add(this.chkUseAlternativeMmc3Irq, 0, 0);
 			this.tableLayoutPanel1.Controls.Add(this.chkAllowInvalidInput, 0, 1);
+			this.tableLayoutPanel1.Controls.Add(this.chkRemoveSpriteLimit, 0, 2);
 			this.tableLayoutPanel1.Dock = System.Windows.Forms.DockStyle.Fill;
 			this.tableLayoutPanel1.Location = new System.Drawing.Point(3, 3);
 			this.tableLayoutPanel1.Name = "tableLayoutPanel1";
-			this.tableLayoutPanel1.RowCount = 2;
+			this.tableLayoutPanel1.RowCount = 4;
+			this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle());
+			this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle(System.Windows.Forms.SizeType.Percent, 100F));
 			this.tableLayoutPanel1.Size = new System.Drawing.Size(380, 207);
@@ -302,6 +306,16 @@
 			this.chkAllowInvalidInput.Text = "Allow invalid input (e.g Down + Up or Left + Right at the same time)";
 			this.chkAllowInvalidInput.UseVisualStyleBackColor = true;
 			// 
+			// chkRemoveSpriteLimit
+			// 
+			this.chkRemoveSpriteLimit.AutoSize = true;
+			this.chkRemoveSpriteLimit.Location = new System.Drawing.Point(3, 49);
+			this.chkRemoveSpriteLimit.Name = "chkRemoveSpriteLimit";
+			this.chkRemoveSpriteLimit.Size = new System.Drawing.Size(205, 17);
+			this.chkRemoveSpriteLimit.TabIndex = 2;
+			this.chkRemoveSpriteLimit.Text = "Remove sprite limit (Reduces flashing)";
+			this.chkRemoveSpriteLimit.UseVisualStyleBackColor = true;
+			// 
 			// frmPreferences
 			// 
 			this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
@@ -352,5 +366,6 @@
 		private System.Windows.Forms.TableLayoutPanel tableLayoutPanel1;
 		private System.Windows.Forms.CheckBox chkUseAlternativeMmc3Irq;
 		private System.Windows.Forms.CheckBox chkAllowInvalidInput;
+		private System.Windows.Forms.CheckBox chkRemoveSpriteLimit;
 	}
 }

GUI.NET/Forms/Config/frmPreferences.cs

@@ -25,6 +25,7 @@ namespace Mesen.GUI.Forms.Config
 
 			AddBinding("UseAlternativeMmc3Irq", chkUseAlternativeMmc3Irq);
 			AddBinding("AllowInvalidInput", chkAllowInvalidInput);
+			AddBinding("RemoveSpriteLimit", chkRemoveSpriteLimit);
 		}
 
 		protected override void OnFormClosed(FormClosedEventArgs e)

GUI.NET/InteropEmu.cs

@@ -432,6 +432,7 @@ namespace Mesen.GUI
 		ShowFPS = 0x02,
 		VerticalSync = 0x04,
 		AllowInvalidInput = 0x08,
+		RemoveSpriteLimit = 0x10,
 		
 		Mmc3IrqAltBehavior = 0x8000,
 	}