The noise pattern can now be harsh

artist/noise.go

@@ -5,18 +5,29 @@ import "image/color"
 // Noisy is a pattern that randomly interpolates between two patterns in a
 // deterministic fashion.
 type Noisy struct {
-	Low  Pattern
-	High Pattern
-	Seed uint32
+	Low   Pattern
+	High  Pattern
+	Seed  uint32
+	Harsh bool
 }
 
 // AtWhen satisfies the pattern interface.
 func (pattern Noisy) AtWhen (x, y, width, height int) (c color.RGBA) {
+	// FIXME: this will occasionally generate "clumps"
 	special := uint32(x + y * 348905)
 	special += (pattern.Seed + 1) * 15485863
 	random := (special * special * special % 2038074743)
 	fac := float64(random) / 2038074743.0
-	return LerpRGBA (
-		pattern.Low.AtWhen(x, y, width, height),
-		pattern.High.AtWhen(x, y, width, height), fac)
+
+	if pattern.Harsh {
+		if fac > 0.5 {
+			return pattern.High.AtWhen(x, y, width, height)
+		} else {
+			return pattern.Low.AtWhen(x, y, width, height)
+		}
+	} else {
+		return LerpRGBA (
+			pattern.Low.AtWhen(x, y, width, height),
+			pattern.High.AtWhen(x, y, width, height), fac)
+	}
 }