fix disk sampler bug

Author: tayloraswift

poisson.png

@@ -66,7 +66,8 @@ struct DiskSampler2D
             queue = [(0.5 * normalized_width, 0.5 * normalized_height)]
         }
 
-        var points:[(Double, Double)] = queue
+        _ = DiskSampler2D.attempt_insert(candidate: queue[0], into_grid: &grid, grid_stride: grid_stride)
+        var points:[(Double, Double)] = [(queue[0].x * radius, queue[0].y * radius)]
         outer: while let front:Math.DoubleV2 = queue.last
         {
             for _ in 0 ..< k

sources/noise/poisson.swift renamed to sources/noise/disk.swift

@@ -10,7 +10,7 @@ import NoiseTests
 
 banners(width: 700, ratio: 5)
 
-
+/*
 var pixbuf:[UInt8]
 let png_properties:PNGProperties = PNGProperties(width: viewer_size, height: viewer_size, bit_depth: 8, color: .grayscale, interlaced: false)!
 
@@ -112,3 +112,4 @@ t0 = clock()
 pixbuf = SS3D.sample_area_saturated_to_u8(width: viewer_size, height: viewer_size, offset: 127.5)
 print(clock() - t0)
 try png_encode(path: "super_simplex3D.png", raw_data: pixbuf, properties: png_properties)
+*/

tests/LinuxMain.swift

@@ -2,6 +2,24 @@ import Noise
 
 import MaxPNG
 
+func write_rgb_png(path:String, width:Int, height:Int, pixbuf:[UInt8])
+{
+    guard let properties = PNGProperties(width: width, height: height, bit_depth: 8, color: .rgb, interlaced: false)
+    else
+    {
+        fatalError("failed to set png properties")
+    }
+
+    do
+    {
+        try png_encode(path: path, raw_data: pixbuf, properties: properties)
+    }
+    catch
+    {
+        print(error)
+    }
+}
+
 func color_noise_png(r_noise:Noise, g_noise:Noise, b_noise:Noise,
     width:Int, height:Int, value_offset:Double, invert:Bool = false, path:String)
 {
@@ -25,20 +43,7 @@ func color_noise_png(r_noise:Noise, g_noise:Noise, b_noise:Noise,
         }
     }
 
-    guard let properties = PNGProperties(width: width, height: height, bit_depth: 8, color: .rgb, interlaced: false)
-    else
-    {
-        fatalError("failed to set png properties")
-    }
-
-    do
-    {
-        try png_encode(path: path, raw_data: pixbuf, properties: properties)
-    }
-    catch
-    {
-        print(error)
-    }
+    write_rgb_png(path: path, width: width, height: height, pixbuf: pixbuf)
 }
 
 func banner_simplex2d(width:Int, height:Int, seed:Int)
@@ -98,6 +103,47 @@ func banner_cell3d(width:Int, height:Int, seed:Int)
                     path: "tests/banner_cell3d.png")
 }
 
+func circle_at(cx:Double, cy:Double, r:Double, width:Int, height:Int, _ f:(Int, Int, Double) -> ())
+{
+    // get bounding box
+    let x1:Int = max(0         , Int(cx - r)),
+        x2:Int = min(width - 1 , Int((cx + r).rounded(.up))),
+        y1:Int = max(0         , Int(cy - r)),
+        y2:Int = min(height - 1, Int((cy + r).rounded(.up)))
+
+    for y in y1 ... y2
+    {
+        let dy:Double = Double(y) - cy
+        for x in x1 ... x2
+        {
+            let dx:Double = Double(x) - cx,
+                dr:Double = (dx*dx + dy*dy).squareRoot()
+
+            f(x, y, min(1, max(0, 1 - dr + r - 0.5)))
+        }
+    }
+}
+
+func banner_disk2d(width:Int, height:Int, seed:Int)
+{
+    var poisson        = DiskSampler2D(seed: seed)
+    var pixbuf:[UInt8] = [UInt8](repeating: 255, count: 3 * width * height)
+
+    let points = poisson.generate(radius: 20, width: width, height: height, k: 80)
+    for point:(x:Double, y:Double) in points
+    {
+        circle_at(cx: point.x, cy: point.y, r: 5, width: width, height: height,
+        {
+            (x:Int, y:Int, v:Double) in
+
+            let base_addr:Int = 3 * (y * width + x)
+            pixbuf[base_addr + 1] = pixbuf[base_addr + 1] &- UInt8(255 * v)
+        })
+    }
+
+    write_rgb_png(path: "tests/banner_disk2d.png", width: width, height: height, pixbuf: pixbuf)
+}
+
 public
 func banners(width:Int, ratio:Double)
 {
@@ -107,4 +153,6 @@ func banners(width:Int, ratio:Double)
     banner_supersimplex3d(width: width, height: height, seed: 0)
     banner_cell2d(width: width, height: height, seed: 0)
     banner_cell3d(width: width, height: height, seed: 0)
+
+    banner_disk2d(width: width, height: height, seed: 0)
 }