Fix solid line under every sprite.

Author: pherrymason

README.md

@@ -17,7 +17,10 @@
   - PPU: Implemented scanline rendering. 
     - Renders contents of CHR ROM
     - Renders background.
-    - Preliminar sprite rendering.
+    - Sprite rendering.
+      - vertical mirror: implemented
+      - horizontal mirror: missing 
+      - 8x16 sprites: missing
   - APU: 0%
   - MMU: 0%
 - UI

src/debugger/controller.go

@@ -98,7 +98,7 @@ func (dbg *GuiDebugger) DrawDebugger(emulator *nes.Nes) {
 	//scale := 3
 	drawASM(emulator)
 	//drawPalettes(emulator, scale, DEBUG_X_OFFSET, 40+15*20, debuggerGUI)
-	//drawCHR(emulator, 2, DEBUG_X_OFFSET, 40+15*20+50, font, debuggerGUI)
+	dbg.drawCHR(emulator, 2, DEBUG_X_OFFSET, 40+15*20+50)
 
 	if emulator.Debugger().DebugPPU {
 		drawPPUDebugger(emulator)
@@ -194,7 +194,7 @@ func drawColorWatch(coordX int, coordY int, width int, height int, color color.C
 	raylib.DrawRectangle(coordX, coordY, width, height, pixelColor2RaylibColor(color))
 }
 
-func drawCHR(console *nes.Nes, scale int, xOffset int, yOffset int, font *raylib.Font, debuggerGUI *GuiDebugger) {
+func (dbg *GuiDebugger) drawCHR(console *nes.Nes, scale int, xOffset int, yOffset int) {
 	drawIndexes := false
 
 	if raylib.IsKeyDown(raylib.KeyZero) {
@@ -207,7 +207,7 @@ func drawCHR(console *nes.Nes, scale int, xOffset int, yOffset int, font *raylib
 	const BorderWidth = 5
 	nextOffsetY := yOffset
 	for patternTableIdx := 0; patternTableIdx < 2; patternTableIdx++ {
-		decodedPatternTable := console.Debugger().PatternTable(byte(patternTableIdx), debuggerGUI.chrPaletteSelector)
+		decodedPatternTable := console.Debugger().PatternTable(byte(patternTableIdx), dbg.chrPaletteSelector)
 		yOffset = nextOffsetY
 
 		for x := 0; x < decodedPatternTable.Bounds().Max.X; x++ {

src/nes/ppu/ppu.go

@@ -261,7 +261,6 @@ func (ppu *P2c02) ResetNmi() {
 */
 func (ppu *P2c02) GetRGBColor(palette byte, colorIndex byte) color.RGBA {
 	paletteColor := ppu.GetPaletteColor(palette, colorIndex)
-	//paletteColor := 1
 	return color.RGBA{
 		R: SystemPalette[paletteColor][0],
 		G: SystemPalette[paletteColor][1],

src/nes/ppu/render.go

@@ -205,7 +205,7 @@ func (ppu *P2c02) finalPixelComposition() {
 
 	var fgPixel byte
 	var fgPalette byte
-	//var fgPriority byte
+	//var fgPriority byte //todo implement priority
 	if ppu.PpuMask.showSpritesEnabled() {
 		for i := byte(0); i < ppu.spriteScanlineCount; i++ {
 			if ppu.oamDataScanline[i].x > 0 {
@@ -300,8 +300,8 @@ func (ppu *P2c02) fetchSpriteShifters() {
 		if ppu.PpuControl.SpriteSize == PPU_CONTROL_SPRITE_SIZE_8 {
 			if !object.isFlippedVertically() {
 				spritePatternAddressLow = types.Address(ppu.PpuControl.SpritePatternTableAddress) << 12
-				spritePatternAddressLow |= types.Address(object.tileId) << 4                       // Multiply ID per 16 (16 bytes per tile)
-				spritePatternAddressLow |= types.Address(ppu.currentScanline - Scanline(object.y)) // Which tile line we want
+				spritePatternAddressLow |= types.Address(object.tileId) << 4                           // Multiply ID per 16 (16 bytes per tile)
+				spritePatternAddressLow |= types.Address(ppu.currentScanline - Scanline(object.y) - 1) // Which tile line we want
 			} else {
 				// TODO implement vertical flip
 			}