get cell noise ready for tilable implentation, still held up by compiler bug

Author: tayloraswift

sources/noise/cell.swift

@@ -1,5 +1,34 @@
+fileprivate
+protocol _CellNoise2D
+{
+    var frequency:Double { get }
+    var amplitude:Double { get }
+    func distance2(from sample_point:Math.DoubleV2, generating_point:Math.IntV2) -> Double
+}
+
+extension _CellNoise2D
+{
+    @inline(__always)
+    func _distance2(hash:Int, sample_point:Math.DoubleV2, generating_point:Math.IntV2) -> Double
+    {
+        // hash is within 0 ... 255, take it to 0 ... 0.5
+
+        // Notice that we have 256 possible hashes, and therefore 8 bits of entropy,
+        // to be divided up between 2 axes. We can assign 4 bits to the x and y
+        // axes each (16 levels each)
+
+        //          0b XXXX YYYY
+
+        let dp:Math.DoubleV2 = ((Double(hash >> 4         ) - 15/2) * 1/16,
+                                (Double(hash      & 0b1111) - 15/2) * 1/16)
+
+        let dv:Math.DoubleV2 = Math.sub(Math.add(Math.cast_double(generating_point), dp), sample_point)
+        return Math.dot(dv, dv)
+    }
+}
+
 public
-struct CellNoise2D:HashedNoise
+struct CellNoise2D:_CellNoise2D, HashedNoise
 {
     let permutation_table:PermutationTable,
         amplitude:Double,
@@ -20,25 +49,13 @@ struct CellNoise2D:HashedNoise
         self.permutation_table = PermutationTable(seed: seed)
     }
 
-    private
+    fileprivate
     func distance2(from sample_point:Math.DoubleV2, generating_point:Math.IntV2) -> Double
     {
-        let hash:Int = self.permutation_table.hash(generating_point)
-        // hash is within 0 ... 255, take it to 0 ... 0.5
-
-        // Notice that we have 256 possible hashes, and therefore 8 bits of entropy,
-        // to be divided up between 2 axes. We can assign 4 bits to the x and y
-        // axes each (16 levels each)
-
-        //          0b XXXX YYYY
-
-        let dp:Math.DoubleV2 = ((Double(hash >> 4         ) - 15/2) * 1/16,
-                                (Double(hash      & 0b1111) - 15/2) * 1/16)
-
-        let dv:Math.DoubleV2 = Math.sub(Math.add(Math.cast_double(generating_point), dp), sample_point)
-        return Math.dot(dv, dv)
+        return self._distance2(hash: self.permutation_table.hash(generating_point), sample_point: sample_point, generating_point: generating_point)
     }
 
+    // still here to make tests run, because of a linker bug in the Swift compiler
     public
     func closest_point(_ x:Double, _ y:Double) -> (point:(Int, Int), r2:Double)
     {

sources/noise/gradient.swift

@@ -17,7 +17,6 @@ protocol _ClassicNoise3D
 extension _ClassicNoise3D
 {
     @inline(__always)
-    fileprivate
     func _gradient(hash:Int, offset:Math.DoubleV3) -> Double
     {
         // use vectors to the edge of a cube
@@ -73,7 +72,7 @@ extension _ClassicNoise3D
 
 // UNDOCUMENTED
 public
-struct ClassicNoise3D:HashedNoise, _ClassicNoise3D
+struct ClassicNoise3D:_ClassicNoise3D, HashedNoise
 {
     let permutation_table:PermutationTable,
         amplitude:Double,
@@ -103,7 +102,7 @@ struct ClassicNoise3D:HashedNoise, _ClassicNoise3D
 
 // UNDOCUMENTED
 public
-struct ClassicTilingNoise3D:HashedTilingNoise, _ClassicNoise3D
+struct ClassicTilingNoise3D:_ClassicNoise3D, HashedTilingNoise
 {
     let permutation_table:PermutationTable,
         amplitude:Double,

tests/LinuxMain.swift

@@ -53,6 +53,14 @@ for (i, (x, y)) in Domain2D(samples_x: viewer_size, samples_y: viewer_size).enum
 print(clock() - t0)
 try png_encode(path: "tests/classic3d.png", raw_data: pixbuf, properties: png_properties)
 
+let PT:Noise = ClassicTilingNoise3D(amplitude: 255, frequency: 16 / Double(viewer_size), wavelengths: 16)
+t0 = clock()
+for (i, (x, y)) in Domain2D(samples_x: viewer_size, samples_y: viewer_size).enumerated()
+{
+    pixbuf[i] = UInt8(max(0, min(255, PT.evaluate(x, y) + 127.5)))
+}
+print(clock() - t0)
+try png_encode(path: "tests/classic_tiling3d.png", raw_data: pixbuf, properties: png_properties)
 
 let SS:FBM<GradientNoise2D> = FBM<GradientNoise2D>(GradientNoise2D(amplitude: 180, frequency: 0.001), octaves: 10, persistence: 0.62)
 t0 = clock()

tests/classic_tiling3d.png

@@ -205,7 +205,7 @@ func banner_disk2d(width:Int, height:Int, seed:Int)
 
 func banner_voronoi2d(width:Int, height:Int, seed:Int)
 {
-    let voronoi          = CellNoise2D(amplitude: 255, frequency: 0.025, seed: seed)
+    let voronoi:CellNoise2D = CellNoise2D(amplitude: 255, frequency: 0.025, seed: seed)
     var pixbytes:[UInt8] = [UInt8](repeating: 0, count: 3 * width * height)
 
     let r:PermutationTable   = PermutationTable(seed: seed),