Precompute the RGBA palette colors

robb · Jun 10, 2018 · 8b3db5b · 8b3db5b
1 parent 2da18d8
commit 8b3db5b
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Showing 3 changed files with 6 additions and 5 deletions.
diff --git a/NES/PPU+IO.swift b/NES/PPU+IO.swift
@@ -42,6 +42,7 @@ extension PPU: IO {
             let mirrored = mirrorPalette(wrappedAddress)
 
             palette[mirrored] = value
+            precomputedPalette[mirrored] = RGBA.from(paletteColor: value)
         default:
             fatalError("Attempt to wirte illegal PPU memory address \(format(address)).")
         }

diff --git a/NES/PPU+Step.swift b/NES/PPU+Step.swift
@@ -68,11 +68,7 @@ internal extension PPU {
 
         let mirrored = mirrorPalette(backgroundPixel)
 
-        let color = palette[mirrored]
-
-        let rgba = RGBA.from(paletteColor: color)
-
-        backBuffer[x, y] = rgba
+        backBuffer[x, y] = precomputedPalette[mirrored]
     }
 
     var backgroundPixel: UInt8 {

diff --git a/NES/PPU.swift b/NES/PPU.swift
@@ -129,8 +129,11 @@ internal final class PPU {
         0x08, 0x3A, 0x00, 0x02, 0x00, 0x20, 0x2C, 0x08
     ]
 
+    var precomputedPalette: UnsafeMutableBufferPointer<RGBA>
+
     init(mapper: Mapper, vram: Data = Data(repeating: 0x00, count: 0x800)) {
         self.mapper = mapper
+        self.precomputedPalette = .from(source: palette.map(RGBA.from))
         self.vram = .from(source: vram)
     }
 
@@ -139,6 +142,7 @@ internal final class PPU {
         frontBuffer.deallocate()
         oam.deallocate()
         palette.deallocate()
+        precomputedPalette.deallocate()
         vram.deallocate()
     }
 }