made roads more dense near city centers

roads.go

@@ -368,11 +368,17 @@ func generatePOIs(width, height int, settings *Settings, waterMask *PixelMask, r
 			break
 		}
 		p := image.Point{X: x, Y: y}
+		centerDist := math.Hypot(float64(x-centerX), float64(y-centerY))
+		centerFactor := 1.0 - clamp01(centerDist/(effectiveRadius+1))
+		localSpacing := avgBuildingSize * (1.36 - 0.68*centerFactor)
+		if localSpacing < 4 {
+			localSpacing = 4
+		}
 		// Keep larger spacing between intersections so buildings have room.
-		if waterMask.GetPoint(p) || isTooCloseToExisting(pois, x, y, avgBuildingSize*1.1) {
+		if waterMask.GetPoint(p) || isTooCloseToExisting(pois, x, y, localSpacing) {
 			continue
 		}
-		pois = append(pois, &PointOfInterest{X: x, Y: y, TargetDegree: sampleTargetDegree(randSrc)})
+		pois = append(pois, &PointOfInterest{X: x, Y: y, TargetDegree: sampleTargetDegree(randSrc, centerFactor)})
 	}
 
 	if len(pois) == 0 {
@@ -383,7 +389,7 @@ func generatePOIs(width, height int, settings *Settings, waterMask *PixelMask, r
 		centerDist := math.Hypot(float64(poi.X-centerX), float64(poi.Y-centerY))
 		centerFactor := 1.0 - clamp01(centerDist/(effectiveRadius+1))
 		sizeFactor := clamp01((avgBuildingSize - 4.0) / 40.0)
-		poi.ArterialWeight = clamp01(0.60*centerFactor + 0.40*sizeFactor)
+		poi.ArterialWeight = clamp01(0.72*centerFactor + 0.28*sizeFactor)
 	}
 
 	return pois
@@ -395,7 +401,7 @@ func estimateCoreNodeCount(width, height int, distribution, avgBuildingSize floa
 	if spacing < 6 {
 		spacing = 6
 	}
-	byArea := int((targetArea / (spacing * spacing)) * 0.18)
+	byArea := int((targetArea / (spacing * spacing)) * 0.20)
 	buildingPressure := int(math.Sqrt(float64(max(numBuildings, 1))) * (0.7 + distribution*0.9))
 	nodes := byArea + buildingPressure
 	if nodes < 8 {
@@ -475,19 +481,22 @@ func sampleEdgePOI(width, height int, randSrc *rand.Rand) *PointOfInterest {
 	}
 }
 
-func sampleTargetDegree(randSrc *rand.Rand) int {
+func sampleTargetDegree(randSrc *rand.Rand, centerFactor float64) int {
+	centerFactor = clamp01(centerFactor)
 	r := randSrc.Float64()
 	switch {
-	case r < 0.03:
+	case r < 0.04-0.02*centerFactor:
 		return 1
-	case r < 0.17:
+	case r < 0.18-0.06*centerFactor:
 		return 2
-	case r < 0.40:
+	case r < 0.42-0.06*centerFactor:
 		return 3
-	case r < 0.85:
+	case r < 0.86-0.20*centerFactor:
 		return 4
-	default:
+	case r < 0.97-0.08*(1.0-centerFactor):
 		return 5
+	default:
+		return 6
 	}
 }
 
@@ -683,7 +692,8 @@ func connectPOIs(pois []*PointOfInterest, width, height int, settings *Settings,
 			b := pois[c.b]
 			centerPenalty := centerCloseness(a) * centerCloseness(b) * 0.45
 			degreePenalty := clamp01(float64(a.Connections+b.Connections) / 8.0)
-			score := c.arterialMean*0.58 + clamp01(c.dist/edgeDist)*0.27 + c.score*0.15 - centerPenalty - degreePenalty*0.18
+			coreBonus := (centerCloseness(a) + centerCloseness(b)) * 0.22
+			score := c.arterialMean*0.58 + clamp01(c.dist/edgeDist)*0.27 + c.score*0.15 + coreBonus - centerPenalty - degreePenalty*0.18
 			if score > bestScore {
 				bestScore = score
 				bestIdx = idx
@@ -733,7 +743,8 @@ func connectPOIs(pois []*PointOfInterest, width, height int, settings *Settings,
 			if !a.IsExit && !b.IsExit {
 				longDiagonalPenalty = clamp01((c.dist-edgeDist*0.45)/(edgeDist*0.35)) * 0.28
 			}
-			score := c.score*0.28 + c.arterialMean*0.27 + distScore*0.35 + connectedBonus - centerPenalty - degreePenalty*0.14 - longDiagonalPenalty
+			coreBonus := (centerCloseness(a) + centerCloseness(b)) * 0.18
+			score := c.score*0.28 + c.arterialMean*0.27 + distScore*0.35 + connectedBonus + coreBonus - centerPenalty - degreePenalty*0.14 - longDiagonalPenalty
 			if score > bestScore {
 				bestScore = score
 				bestIdx = idx
@@ -776,6 +787,9 @@ func connectPOIs(pois []*PointOfInterest, width, height int, settings *Settings,
 		if !a.IsExit && !b.IsExit && pick.dist > edgeDist*0.42 {
 			continue
 		}
+		if centerCloseness(a)+centerCloseness(b) < 0.35 && randSrc.Float64() < 0.55 {
+			continue
+		}
 		addEdge(pick, RoadTierLocal)
 	}