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| 1 | +/** |
| 2 | + * @fileoverview |
| 3 | + * 实验性的随机控制点生成函数算法 |
| 4 | + * 目的是取代原先大量的预设控制点代码 |
| 5 | + */ |
| 6 | + |
| 7 | +import { |
| 8 | + type ControlPointConf, |
| 9 | + type ControlPointPreset, |
| 10 | + p, |
| 11 | + preset, |
| 12 | +} from "./cp-presets.ts"; |
| 13 | + |
| 14 | +const randomRange = (min: number, max: number): number => |
| 15 | + Math.random() * (max - min) + min; |
| 16 | + |
| 17 | +function clamp(x: number, min: number, max: number): number { |
| 18 | + return Math.min(Math.max(x, min), max); |
| 19 | +} |
| 20 | + |
| 21 | +function smoothstep(edge0: number, edge1: number, x: number): number { |
| 22 | + const t = clamp((x - edge0) / (edge1 - edge0), 0, 1); |
| 23 | + return t * t * (3 - 2 * t); |
| 24 | +} |
| 25 | + |
| 26 | +function smoothifyControlPoints( |
| 27 | + conf: ControlPointConf[], |
| 28 | + w: number, |
| 29 | + h: number, |
| 30 | + iterations = 2, |
| 31 | + factor = 0.5, |
| 32 | + factorIterationModifier = 0.1, |
| 33 | +): void { |
| 34 | + let grid: ControlPointConf[][] = []; |
| 35 | + let f = factor; |
| 36 | + |
| 37 | + for (let j = 0; j < h; j++) { |
| 38 | + grid[j] = []; |
| 39 | + for (let i = 0; i < w; i++) { |
| 40 | + grid[j][i] = conf[j * w + i]; |
| 41 | + } |
| 42 | + } |
| 43 | + |
| 44 | + const kernel = [ |
| 45 | + [1, 2, 1], |
| 46 | + [2, 4, 2], |
| 47 | + [1, 2, 1], |
| 48 | + ]; |
| 49 | + const kernelSum = 16; |
| 50 | + |
| 51 | + for (let iter = 0; iter < iterations; iter++) { |
| 52 | + const newGrid: ControlPointConf[][] = []; |
| 53 | + for (let j = 0; j < h; j++) { |
| 54 | + newGrid[j] = []; |
| 55 | + for (let i = 0; i < w; i++) { |
| 56 | + if (i === 0 || i === w - 1 || j === 0 || j === h - 1) { |
| 57 | + newGrid[j][i] = grid[j][i]; |
| 58 | + continue; |
| 59 | + } |
| 60 | + let sumX = 0; |
| 61 | + let sumY = 0; |
| 62 | + let sumUR = 0; |
| 63 | + let sumVR = 0; |
| 64 | + let sumUP = 0; |
| 65 | + let sumVP = 0; |
| 66 | + for (let dj = -1; dj <= 1; dj++) { |
| 67 | + for (let di = -1; di <= 1; di++) { |
| 68 | + const weight = kernel[dj + 1][di + 1]; |
| 69 | + const nb = grid[j + dj][i + di]; |
| 70 | + sumX += nb.x * weight; |
| 71 | + sumY += nb.y * weight; |
| 72 | + sumUR += nb.ur * weight; |
| 73 | + sumVR += nb.vr * weight; |
| 74 | + sumUP += nb.up * weight; |
| 75 | + sumVP += nb.vp * weight; |
| 76 | + } |
| 77 | + } |
| 78 | + const avgX = sumX / kernelSum; |
| 79 | + const avgY = sumY / kernelSum; |
| 80 | + const avgUR = sumUR / kernelSum; |
| 81 | + const avgVR = sumVR / kernelSum; |
| 82 | + const avgUP = sumUP / kernelSum; |
| 83 | + const avgVP = sumVP / kernelSum; |
| 84 | + |
| 85 | + const cur = grid[j][i]; |
| 86 | + const newX = cur.x * (1 - f) + avgX * f; |
| 87 | + const newY = cur.y * (1 - f) + avgY * f; |
| 88 | + const newUR = cur.ur * (1 - f) + avgUR * f; |
| 89 | + const newVR = cur.vr * (1 - f) + avgVR * f; |
| 90 | + const newUP = cur.up * (1 - f) + avgUP * f; |
| 91 | + const newVP = cur.vp * (1 - f) + avgVP * f; |
| 92 | + newGrid[j][i] = p(i, j, newX, newY, newUR, newVR, newUP, newVP); |
| 93 | + } |
| 94 | + } |
| 95 | + grid = newGrid; |
| 96 | + f = Math.min(1, Math.max(f + factorIterationModifier, 0)); |
| 97 | + } |
| 98 | + |
| 99 | + for (let j = 0; j < h; j++) { |
| 100 | + for (let i = 0; i < w; i++) { |
| 101 | + conf[j * w + i] = grid[j][i]; |
| 102 | + } |
| 103 | + } |
| 104 | +} |
| 105 | + |
| 106 | +function noise(x: number, y: number): number { |
| 107 | + return fract(Math.sin(x * 12.9898 + y * 78.233) * 43758.5453); |
| 108 | +} |
| 109 | + |
| 110 | +function fract(x: number): number { |
| 111 | + return x - Math.floor(x); |
| 112 | +} |
| 113 | + |
| 114 | +function smoothNoise(x: number, y: number): number { |
| 115 | + const x0 = Math.floor(x); |
| 116 | + const y0 = Math.floor(y); |
| 117 | + const x1 = x0 + 1; |
| 118 | + const y1 = y0 + 1; |
| 119 | + |
| 120 | + const xf = x - x0; |
| 121 | + const yf = y - y0; |
| 122 | + |
| 123 | + const u = xf * xf * (3 - 2 * xf); |
| 124 | + const v = yf * yf * (3 - 2 * yf); |
| 125 | + |
| 126 | + const n00 = noise(x0, y0); |
| 127 | + const n10 = noise(x1, y0); |
| 128 | + const n01 = noise(x0, y1); |
| 129 | + const n11 = noise(x1, y1); |
| 130 | + |
| 131 | + const nx0 = n00 * (1 - u) + n10 * u; |
| 132 | + const nx1 = n01 * (1 - u) + n11 * u; |
| 133 | + |
| 134 | + return nx0 * (1 - v) + nx1 * v; |
| 135 | +} |
| 136 | + |
| 137 | +function computeNoiseGradient( |
| 138 | + perlinFn: (x: number, y: number) => number, |
| 139 | + x: number, |
| 140 | + y: number, |
| 141 | + epsilon = 0.001, |
| 142 | +): [number, number] { |
| 143 | + const n1 = perlinFn(x + epsilon, y); |
| 144 | + const n2 = perlinFn(x - epsilon, y); |
| 145 | + const n3 = perlinFn(x, y + epsilon); |
| 146 | + const n4 = perlinFn(x, y - epsilon); |
| 147 | + const dx = (n1 - n2) / (2 * epsilon); |
| 148 | + const dy = (n3 - n4) / (2 * epsilon); |
| 149 | + const len = Math.sqrt(dx * dx + dy * dy) || 1; |
| 150 | + return [dx / len, dy / len]; |
| 151 | +} |
| 152 | + |
| 153 | +export function generateControlPoints( |
| 154 | + width: number, |
| 155 | + height: number, |
| 156 | + variationFraction = randomRange(0.4, 0.6), // = 0.2, |
| 157 | + normalOffset = randomRange(0.3, 0.6), // = 0.3, |
| 158 | + blendFactor = 0.8, |
| 159 | + smoothIters = Math.floor(randomRange(3, 5)), // = 3, |
| 160 | + smoothFactor = randomRange(0.2, 0.3), // = 0.3, |
| 161 | + smoothModifier = randomRange(-0.1, -0.05), // = -0.05, |
| 162 | +): ControlPointPreset { |
| 163 | + const w = width ?? Math.floor(randomRange(3, 6)); |
| 164 | + const h = height ?? Math.floor(randomRange(3, 6)); |
| 165 | + |
| 166 | + const conf: ControlPointConf[] = []; |
| 167 | + const dx = w === 1 ? 0 : 2 / (w - 1); |
| 168 | + const dy = h === 1 ? 0 : 2 / (h - 1); |
| 169 | + |
| 170 | + for (let j = 0; j < h; j++) { |
| 171 | + for (let i = 0; i < w; i++) { |
| 172 | + const baseX = (w === 1 ? 0 : i / (w - 1)) * 2 - 1; |
| 173 | + const baseY = (h === 1 ? 0 : j / (h - 1)) * 2 - 1; |
| 174 | + |
| 175 | + const isBorder = i === 0 || i === w - 1 || j === 0 || j === h - 1; |
| 176 | + const pertX = isBorder |
| 177 | + ? 0 |
| 178 | + : randomRange(-variationFraction * dx, variationFraction * dx); |
| 179 | + const pertY = isBorder |
| 180 | + ? 0 |
| 181 | + : randomRange(-variationFraction * dy, variationFraction * dy); |
| 182 | + let x = baseX + pertX; |
| 183 | + let y = baseY + pertY; |
| 184 | + |
| 185 | + const ur = isBorder ? 0 : randomRange(-60, 60); |
| 186 | + const vr = isBorder ? 0 : randomRange(-60, 60); |
| 187 | + const up = isBorder ? 1 : randomRange(0.8, 1.2); |
| 188 | + const vp = isBorder ? 1 : randomRange(0.8, 1.2); |
| 189 | + |
| 190 | + if (!isBorder) { |
| 191 | + const uNorm = (baseX + 1) / 2; |
| 192 | + const vNorm = (baseY + 1) / 2; |
| 193 | + |
| 194 | + const [nx, ny] = computeNoiseGradient(smoothNoise, uNorm, vNorm, 0.001); |
| 195 | + let offsetX = nx * normalOffset; |
| 196 | + let offsetY = ny * normalOffset; |
| 197 | + |
| 198 | + const distToBorder = Math.min(uNorm, 1 - uNorm, vNorm, 1 - vNorm); // in [0,0.5] |
| 199 | + |
| 200 | + const weight = smoothstep(0, 1.0, distToBorder); |
| 201 | + offsetX *= weight; |
| 202 | + offsetY *= weight; |
| 203 | + |
| 204 | + x = x * (1 - blendFactor) + (x + offsetX) * blendFactor; |
| 205 | + y = y * (1 - blendFactor) + (y + offsetY) * blendFactor; |
| 206 | + } |
| 207 | + conf.push(p(i, j, x, y, ur, vr, up, vp)); |
| 208 | + } |
| 209 | + } |
| 210 | + |
| 211 | + smoothifyControlPoints(conf, w, h, smoothIters, smoothFactor, smoothModifier); |
| 212 | + |
| 213 | + return preset(w, h, conf); |
| 214 | +} |
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