function generateBlueNoise(count, minDistance = 0.9 / Math.sqrt(count)) { if (!Number.isFinite(count) || count <= 0) return new Float32Array(0); const cellSize = minDistance / Math.SQRT2; const gridSize = Math.max(1, Math.ceil(1 / cellSize)); const grid = new Int32Array(gridSize * gridSize).fill(-1); const minDist2 = minDistance * minDistance; const points = []; const active = []; function gridIndex(x, y) { const gx = Math.min(gridSize - 1, Math.floor(x / cellSize)); const gy = Math.min(gridSize - 1, Math.floor(y / cellSize)); return { gx, gy }; } function isValid(x, y) { if (x < 0 || x >= 1 || y < 0 || y >= 1) return false; const { gx, gy } = gridIndex(x, y); for (let cellY = -2; cellY <= 2; ++cellY) { const yy = gy + cellY; if (yy < 0 || yy >= gridSize) continue; for (let cellX = -2; cellX <= 2; ++cellX) { const xx = gx + cellX; if (xx < 0 || xx >= gridSize) continue; const i = grid[yy * gridSize + xx]; if (i < 0) continue; const dx = x - points[i][0]; const dy = y - points[i][1]; if (dx * dx + dy * dy < minDist2) return false; } } return true; } function addPoint(x, y) { const idx = points.length; points.push([x, y]); active.push(idx); const { gx, gy } = gridIndex(x, y); grid[gy * gridSize + gx] = idx; } addPoint(Math.random(), Math.random()); const k = 30; // candidates per active point, standard Bridson value while (active.length > 0 && points.length < count) { const activeIdx = Math.floor(Math.random() * active.length); const [px, py] = points[active[activeIdx]]; let found = false; for (let i = 0; i < k; ++i) { const angle = Math.random() * Math.PI * 2; const radius = minDistance * (1 + Math.random()); // [r, 2r] const x = px + Math.cos(angle) * radius; const y = py + Math.sin(angle) * radius; if (isValid(x, y)) { addPoint(x, y); found = true; if (points.length >= count) break; } } if (!found) { active.splice(activeIdx, 1); // dead end, retire this point } } const out = new Float32Array(points.length * 2); for (let i = 0; i < points.length; ++i) { out[i * 2] = points[i][0]; out[i * 2 + 1] = points[i][1]; } return out; }