webcam_script = { const blob = new Blob([` importScripts("${await require.resolve("d3-delaunay@3")}"); let totalPoints = 0; let n = 0; let k = 0; let iterations = 0; let width = 0; let height = 0; let sobelRatio = 0.5; let data, sobelData, summedWeights, points, sobelPoints, velocities, weights, sobelWeights, c, sc; let rendering = false; function init(event){ // const {data: {data, sobelData, width, height, n, iterations, sobelRatio}} = event.data; k = 0; n = event.data.n; if (!(n > 0)){ iterations = 0; return; } iterations; iterations = event.data.iterations; width = event.data.width; height = event.data.height; data = event.data.data; sobelData = event.data.sobelData; sobelRatio = event.data.sobelRatio; // re-use TypedArrays for reduced GC pressure. if (n !== totalPoints) { totalPoints = n; // x and y positions for each Voronoi cell. points = new Float32Array(n * 2); sobelPoints = new Float32Array(n * 2); velocities = new Float32Array(n * 2); // summing the weights of each voronoi cell weights = new Float32Array(n); sobelWeights = new Float32Array(n); // sum of weighted x and y positions for each voronoi cell c = new Float32Array(n * 2); sc = new Float32Array(n * 2); } else { // Avoid re-allocating the buffers all the time points.fill(0); sobelPoints.fill(0); velocities.fill(0); weights.fill(0); sobelWeights.fill(0); c.fill(0); sc.fill(0); } if (!summedWeights || summedWeights.length < width * height){ summedWeights = new Float32Array(width * height); } // calculate summed weight with sobelRatio once and reuse for (let y = 0, i = 0; y < height; ++y) { for (let x = 0; x < width; ++x) { const j = y * width + x; const lightnessWeight = data[j]; const sobelWeight = sobelData[j]; summedWeights[j] = (1-sobelRatio) * lightnessWeight + sobelWeight * sobelRatio; } } // Initialize the points using rejection sampling. for (let i = 0; i < n; ++i) { let x = 0, y = 0; // try up to thirty times for(let j = 0, rejected = true; j < 100 && rejected; j++) { x = Math.floor(Math.random() * width); y = Math.floor(Math.random() * height); const summedWeight = summedWeights[y * width + x]; rejected = Math.random() > summedWeight; } sobelPoints[i * 2] = x; sobelPoints[i * 2 + 1] = y; } if (!rendering) { rendering = true; setTimeout(render, 0); } } function render(){ if(++k > iterations){ rendering = false; return; } const delaunay = new d3.Delaunay(sobelPoints); const voronoi = delaunay.voronoi([0, 0, width, height]); // Compute the Sobel-weighted centroid for each Voronoi cell. sc.fill(0); sobelWeights.fill(0); for (let y = 0, i = 0; y < height; ++y) { for (let x = 0; x < width; ++x) { i = voronoi.find(x + 0.5, y + 0.5, i); const summedWeight = summedWeights[y * width + x]; sobelWeights[i] += summedWeight; sc[i * 2] += summedWeight * (x + 0.5); sc[i * 2 + 1] += summedWeight * (y + 0.5); } } // Relax the diagram by moving points to the weighted centroid. // Wiggle the points a little bit so they don’t get stuck. const wiggle = Math.pow(k + 1, -0.8)*2; for (let i = 0; i < n; ++i) { let x0 = sobelPoints[i * 2]; let y0 = sobelPoints[i * 2 + 1]; let x1 = x0; let y1 = y0; let weight = sobelWeights[i]; if (weight) { x1 = sc[i * 2] / weight; y1 = sc[i * 2 + 1] / weight; } let vx = velocities[i * 2] * Math.SQRT1_2 + (x1-x0); let vy = velocities[i * 2 + 1] * Math.SQRT1_2 + (y1-y0); velocities[i * 2] = vx; velocities[i * 2 + 1] = vy; x0 += vx; y0 += vy; sobelPoints[i * 2] = x0 > 0 ? (x0 < width-1 ? x0 : width-2) : 1; sobelPoints[i * 2 + 1] = y0 > 0 ? (y0 < height-1 ? y0 : height-2) : 1; } // For performance purposes we don't render each iteration. // The weights and centroids for lightness coverage are // calculated only when a frame is rendered, since that is // the only time we actually need them. if(true || k%4 == 0 || k+1 == iterations) { c.fill(0); weights.fill(0); // reuse sc + sobelWeights as unweighted centroid sc.fill(0); sobelWeights.fill(0); for (let y = 0, i = 0; y < height; ++y) { for (let x = 0; x < width; ++x) { i = voronoi.find(x + 0.5, y + 0.5, i); const weight = data[y * width + x]; weights[i] += weight; c[i * 2] += weight * (x + 0.5); c[i * 2 + 1] += weight * (y + 0.5); sobelWeights[i] += 1; sc[i * 2] += (x + 0.5); sc[i * 2 + 1] += (y + 0.5); } } for (let i = 0; i < n; ++i) { let x0 = 0; let y0 = 0; let weight = weights[i]; if (weight) { x0 = c[i * 2] / weight; y0 = c[i * 2 + 1] / weight; } else { weight = sobelWeights[i]; if (!weight) weight = 1; x0 = sobelPoints[i * 2] / weight; y0 = sobelPoints[i * 2 + 1] / weight; } points[i * 2] = x0; points[i * 2 + 1] = y0; } postMessage({points, weights}); } setTimeout(render, 0); } onmessage = event => { switch(event.data.msg){ case 'render': init(event); break; case 'newFrame': data = event.data.data; break; } }; `], {type: "text/javascript"}); const script = URL.createObjectURL(blob); invalidation.then(() => URL.revokeObjectURL(script)); return script; }