Frequency control for noise

app/Main.hs

@@ -152,7 +152,7 @@ perlinSpheresScene w aspectRatio samplesPerPixel maxDepth gen = do
           focusDist
           samplesPerPixel
           maxDepth
-  perlinTexture <- mkNoiseTexture gen
+  perlinTexture <- mkNoiseTexture gen 4
   let perlinSurface = Lambertian perlinTexture
       sphereGround = mkSomeObject (mkSphere (fromXYZ (0, -1000, 0)) 1000) perlinSurface
       sphere1 = mkSomeObject (mkSphere (fromXYZ (0, 2, 0)) 2.0) perlinSurface

app/Texture/Perlin.hs

@@ -84,15 +84,15 @@ noise perlin point = trilinearInterpolation c u' v' w'
             values perlin V.! (dx `xor` dy `xor` dz)
         )
 
-newtype NoiseTexture = NoiseTexture Perlin
+data NoiseTexture = NoiseTexture !Perlin !Double
 
 instance Show NoiseTexture where
   show _ = "Noise Texture"
 
 instance Texture NoiseTexture where
-  value (NoiseTexture perlin) _u _v point = fromXYZ (1, 1, 1) .^ noise perlin point
+  value (NoiseTexture perlin scale) _u _v point = fromXYZ (1, 1, 1) .^ noise perlin (point .^ scale)
 
-mkNoiseTexture :: (StatefulGen g m, PrimMonad m) => g -> m NoiseTexture
-mkNoiseTexture gen = do
+mkNoiseTexture :: (StatefulGen g m, PrimMonad m) => g -> Double -> m NoiseTexture
+mkNoiseTexture gen scale = do
   perlin <- mkPerlin gen
-  pure $ NoiseTexture perlin
+  pure $ NoiseTexture perlin scale