add lacunarity parameter to fBm noise generator

tayloraswift · tayloraswift · commit 9b540bde30cd · 2017-06-10T01:49:06.000-04:00
diff --git a/sources/noise/noise.swift b/sources/noise/noise.swift
@@ -67,7 +67,7 @@ struct fBm<Generator:Noise>:Noise
     }
 
     public
-    init(amplitude:Double, frequency:Double, octaves:Int, persistence:Double = 0.75, seed:Int = 0)
+    init(amplitude:Double, frequency:Double, octaves:Int, persistence:Double = 0.75, lacunarity:Double = 2, seed:Int = 0)
     {
         var generators:[Generator] = []
             generators.reserveCapacity(octaves)
@@ -77,7 +77,7 @@ struct fBm<Generator:Noise>:Noise
         {
             generators.append(Generator(amplitude: a, frequency: f, seed: s))
             a *= persistence
-            f *= 2
+            f *= lacunarity
         }
 
         self.generators  = generators

Original file line number	Diff line number	Diff line change
`@@ -67,7 +67,7 @@ struct fBm<Generator:Noise>:Noise`
`67`	`67`	`}`
`68`	`68`
`69`	`69`	`public`
`70`		`- init(amplitude:Double, frequency:Double, octaves:Int, persistence:Double = 0.75, seed:Int = 0)`
	`70`	`+ init(amplitude:Double, frequency:Double, octaves:Int, persistence:Double = 0.75, lacunarity:Double = 2, seed:Int = 0)`
`71`	`71`	`{`
`72`	`72`	`var generators:[Generator] = []`
`73`	`73`	`generators.reserveCapacity(octaves)`
`@@ -77,7 +77,7 @@ struct fBm<Generator:Noise>:Noise`
`77`	`77`	`{`
`78`	`78`	`generators.append(Generator(amplitude: a, frequency: f, seed: s))`
`79`	`79`	`a *= persistence`
`80`		`- f *= 2`
	`80`	`+ f *= lacunarity`
`81`	`81`	`}`
`82`	`82`
`83`	`83`	`self.generators = generators`