add uniformity option

Author: bobnik

PR.md

@@ -1,18 +1,15 @@
-## Optimize Voronoi effect performance
+## Optimize Voronoi and add uniformity option
 
-Replaced Dijkstra with BFS for shortest path finding in graph traversal, since all edge weights are uniform (1).
-
-**Changes:**
-- `src/common/Graph.js`: Added `bfsShortestPath()` - O(V+E) vs original O(V²)
-- `src/common/Graph.js`: Removed cache invalidation during graph construction
-- `src/common/voronoi.js`: Use `bfsShortestPath()`
-- `src/common/lindenmayer.js`: Use `bfsShortestPath()`
-- `src/features/shapes/tessellation_twist/TessellationTwist.js`: Use `bfsShortestPath()`
-- `src/features/effects/effectFactory.js`: Re-enabled Voronoi effect
+Replaced Dijkstra with BFS for shortest path finding in graph traversal, since all edge weights are uniform (1). Added Lloyd relaxation as a "Uniformity" slider to both Voronoi shape and effect.
 
 **Performance improvement:**
 ~200x faster path finding (BFS O(V+E) vs old Dijkstra with O(n) priority queue)
 
+**Uniformity option:**
+- 0 (default): original chaotic/irregular cells
+- 5-10: cells approach uniform hexagons (honeycomb aesthetic)
+- Works with both voronoi and delaunay polygon types
+- Complements weight functions: weight controls density, uniformity controls regularity
+
 **Notes:**
 - `dijkstraShortestPath()` kept for future weighted edge use cases
-- Path cache note added for future maintainers

src/common/voronoi.js

@@ -234,6 +234,7 @@ export class VoronoiMixin {
       voronoiMinDistance,
       voronoiMaxDistance,
       voronoiZoom,
+      voronoiUniformity = 0,
     } = options
     const width =
       voronoiPlacement == "poisson disk sampling"
@@ -270,6 +271,10 @@ export class VoronoiMixin {
       })
     }
 
+    if (voronoiUniformity > 0) {
+      points = this.relaxPoints(points, width, height, voronoiUniformity)
+    }
+
     return points
   }
 
@@ -337,4 +342,44 @@ export class VoronoiMixin {
 
     return graph.findNode(onEdge) || closestNode
   }
+
+  // Lloyd relaxation: move each point to the centroid of its Voronoi cell
+  relaxPoints(points, width, height, iterations) {
+    let relaxedPoints = points
+
+    for (let i = 0; i < iterations; i++) {
+      const delaunay = Delaunay.from(relaxedPoints)
+      const voronoi = delaunay.voronoi([0, 0, width, height])
+
+      relaxedPoints = relaxedPoints.map((point, idx) => {
+        const cell = voronoi.cellPolygon(idx)
+        if (!cell || cell.length < 3) return point
+
+        // Calculate centroid of the cell polygon
+        let cx = 0
+        let cy = 0
+        let area = 0
+
+        for (let j = 0; j < cell.length - 1; j++) {
+          const [x0, y0] = cell[j]
+          const [x1, y1] = cell[j + 1]
+          const cross = x0 * y1 - x1 * y0
+
+          area += cross
+          cx += (x0 + x1) * cross
+          cy += (y0 + y1) * cross
+        }
+
+        area /= 2
+        if (Math.abs(area) < 1e-10) return point
+
+        cx /= 6 * area
+        cy /= 6 * area
+
+        return [cx, cy]
+      })
+    }
+
+    return relaxedPoints
+  }
 }

src/features/effects/Voronoi.js

@@ -23,6 +23,12 @@ export const voronoiOptions = {
     type: "togglebutton",
     choices: ["voronoi", "delaunay"],
   },
+  voronoiUniformity: {
+    title: "Uniformity",
+    type: "slider",
+    min: 0,
+    max: 20,
+  },
 }
 
 export default class Voronoi extends Effect {
@@ -51,14 +57,16 @@ export default class Voronoi extends Effect {
       ...super.getInitialState(),
       ...{
         voronoiPolygon: "voronoi",
+        voronoiUniformity: 0,
         seed: 1,
       },
     }
   }
 
   getVertices(effect, layer, vertices) {
-    const { seed, voronoiPolygon } = effect
+    const { seed, voronoiPolygon, voronoiUniformity = 0 } = effect
     const { width, height } = dimensions(vertices)
+
     this.rng = seedrandom(seed)
     noise.seed(seed)
 
@@ -68,7 +76,12 @@ export default class Voronoi extends Effect {
       ),
       (vertex) => vertex.toString(),
     )
-    const points = this.generatePointsFromVertices(mappedVertices)
+    let points = this.generatePointsFromVertices(mappedVertices)
+
+    if (voronoiUniformity > 0) {
+      points = this.relaxPoints(points, width, height, voronoiUniformity)
+    }
+
     this.graph = this.buildGraph(points, voronoiPolygon, width, height)
 
     this.vertices = []

src/features/shapes/Voronoi.js

@@ -77,6 +77,12 @@ export const voronoiOptions = {
       )
     },
   },
+  voronoiUniformity: {
+    title: "Uniformity",
+    type: "slider",
+    min: 0,
+    max: 20,
+  },
   seed: {
     title: "Random seed",
     min: 1,
@@ -107,6 +113,7 @@ export default class Voronoi extends Shape {
         voronoiMinDistance: 30,
         voronoiMaxDistance: 50,
         voronoiFrequency: 5,
+        voronoiUniformity: 0,
         seed: 1,
       },
     }