66 lines
2.2 KiB
C#
66 lines
2.2 KiB
C#
using System.Collections;
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using System.Collections.Generic;
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using UnityEngine;
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public static class PoissonDiscSampling {
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public static List<Vector2> GeneratePoints(float radius, Vector2 sampleRegionSize, int numSamplesBeforeRejection = 30) {
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float cellSize = radius/Mathf.Sqrt(2);
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int[,] grid = new int[Mathf.CeilToInt(sampleRegionSize.x/cellSize), Mathf.CeilToInt(sampleRegionSize.y/cellSize)];
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List<Vector2> points = new List<Vector2>();
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List<Vector2> spawnPoints = new List<Vector2>();
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spawnPoints.Add(sampleRegionSize/2);
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while (spawnPoints.Count > 0) {
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int spawnIndex = Random.Range(0,spawnPoints.Count);
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Vector2 spawnCentre = spawnPoints[spawnIndex];
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bool candidateAccepted = false;
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for (int i = 0; i < numSamplesBeforeRejection; i++)
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{
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float angle = Random.value * Mathf.PI * 2;
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Vector2 dir = new Vector2(Mathf.Sin(angle), Mathf.Cos(angle));
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Vector2 candidate = spawnCentre + dir * Random.Range(radius, 2*radius);
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if (IsValid(candidate, sampleRegionSize, cellSize, radius, points, grid)) {
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points.Add(candidate);
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spawnPoints.Add(candidate);
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grid[(int)(candidate.x/cellSize),(int)(candidate.y/cellSize)] = points.Count;
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candidateAccepted = true;
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break;
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}
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}
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if (!candidateAccepted) {
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spawnPoints.RemoveAt(spawnIndex);
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}
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}
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return points;
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}
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static bool IsValid(Vector2 candidate, Vector2 sampleRegionSize, float cellSize, float radius, List<Vector2> points, int[,] grid) {
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if (candidate.x >=0 && candidate.x < sampleRegionSize.x && candidate.y >= 0 && candidate.y < sampleRegionSize.y) {
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int cellX = (int)(candidate.x/cellSize);
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int cellY = (int)(candidate.y/cellSize);
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int searchStartX = Mathf.Max(0,cellX -2);
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int searchEndX = Mathf.Min(cellX+2,grid.GetLength(0)-1);
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int searchStartY = Mathf.Max(0,cellY -2);
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int searchEndY = Mathf.Min(cellY+2,grid.GetLength(1)-1);
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for (int x = searchStartX; x <= searchEndX; x++) {
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for (int y = searchStartY; y <= searchEndY; y++) {
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int pointIndex = grid[x,y]-1;
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if (pointIndex != -1) {
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float sqrDst = (candidate - points[pointIndex]).sqrMagnitude;
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if (sqrDst < radius*radius) {
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return false;
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}
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}
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}
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}
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return true;
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}
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return false;
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}
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} |