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ai.interactive.fiction/public/js/webgl-book-shape-lab.js
T
2026-06-05 03:32:50 +02:00

1055 lines
40 KiB
JavaScript

import * as THREE from 'https://esm.sh/three@0.165.0';
import { OrbitControls } from 'https://esm.sh/three@0.165.0/examples/jsm/controls/OrbitControls.js';
const canvas = document.getElementById('scene');
const progressInput = document.getElementById('progress');
const progressValue = document.getElementById('progress_value');
const pageCountInput = document.getElementById('page_count');
const pageCountValue = document.getElementById('page_count_value');
const flipBackwardButton = document.getElementById('flip_backward');
const flipForwardButton = document.getElementById('flip_forward');
const flipCountValue = document.getElementById('flip_count');
const urlParams = new URLSearchParams(window.location.search);
const renderer = new THREE.WebGLRenderer({ canvas, antialias: true });
renderer.setPixelRatio(Math.min(window.devicePixelRatio || 1, 2));
renderer.setClearColor(0x202124, 1);
const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(34, 1, 0.1, 30);
if (urlParams.get('view') === 'profile') {
camera.position.set(0, 0.82, 5.8);
} else if (urlParams.get('view') === 'top') {
camera.position.set(0, 5.8, 0.001);
} else {
camera.position.set(0, 3.25, 5.4);
}
const controls = new OrbitControls(camera, canvas);
controls.target.set(0, urlParams.get('view') === 'profile' ? 0.13 : 0.18, 0);
controls.enableDamping = true;
controls.minDistance = 2.2;
controls.maxDistance = 8.0;
controls.update();
const book = new THREE.Group();
scene.add(book);
const guide = new THREE.GridHelper(5.6, 16, 0x4c4c4c, 0x343434);
guide.position.y = -0.12;
scene.add(guide);
const materials = {
cover: new THREE.MeshBasicMaterial({ color: 0x2c1810, side: THREE.DoubleSide }),
spine: new THREE.MeshBasicMaterial({ color: 0x9c1f1f, side: THREE.DoubleSide }),
pagesLeft: new THREE.MeshBasicMaterial({ color: 0xd8c7a4, side: THREE.DoubleSide }),
pagesRight: new THREE.MeshBasicMaterial({ color: 0xe7d6b4, side: THREE.DoubleSide }),
topPage: new THREE.MeshBasicMaterial({ color: 0xf1dfba, side: THREE.DoubleSide }),
flippingPage: new THREE.MeshBasicMaterial({ color: 0xf3dfb6, side: THREE.DoubleSide }),
edge: new THREE.MeshBasicMaterial({ color: 0xb99a68, side: THREE.DoubleSide }),
hinge: new THREE.MeshBasicMaterial({ color: 0x2b0808 })
};
const BOOK_PROFILE = {
tableY: 0,
coverThickness: 0.03,
raisedHingeY: 0.056,
paperContactOffset: 0.0012,
singlePageCoverGap: 0.006,
bundleSpacing: 0.014
};
let readingProgress = readInitialProgress();
let pageCount = readInitialPageCount();
let lastLengthError = 0;
let lastSpacingError = 0;
let lastBookModel = null;
let activeFlip = null;
let activeFlipMesh = null;
let pendingPageFlips = 0;
progressInput.value = readingProgress.toFixed(3);
progressValue.value = readingProgress.toFixed(2);
pageCountInput.value = String(pageCount);
pageCountValue.value = String(pageCount);
updateFlipControls();
rebuildBook();
resize();
animate();
progressInput.addEventListener('input', () => {
setReadingProgress(progressInput.value);
});
pageCountInput.addEventListener('input', () => {
setPageCount(pageCountInput.value);
});
flipBackwardButton.addEventListener('click', () => {
startPageFlip(-1);
});
flipForwardButton.addEventListener('click', () => {
startPageFlip(1);
});
window.addEventListener('resize', resize);
window.BookShapeLab = {
get progress() {
return readingProgress;
},
get pageCount() {
return pageCount;
},
get lastLengthError() {
return lastLengthError;
},
get lastSpacingError() {
return lastSpacingError;
},
setReadingProgress(value) {
setReadingProgress(value);
return readingProgress;
},
setPageCount(value) {
setPageCount(value);
return pageCount;
},
flipForward() {
return startPageFlip(1);
},
flipBackward() {
return startPageFlip(-1);
}
};
function readInitialProgress() {
const parsed = Number.parseFloat(urlParams.get('progress') ?? '0.25');
return Number.isFinite(parsed) ? THREE.MathUtils.clamp(parsed, 0, 1) : 0.25;
}
function readInitialPageCount() {
const parsed = Number.parseInt(urlParams.get('pages') ?? '240', 10);
if (!Number.isFinite(parsed)) return 240;
return snapPageCount(parsed);
}
function snapPageCount(value) {
return THREE.MathUtils.clamp(Math.round(value / 10) * 10, 40, 600);
}
function setReadingProgress(value) {
const next = THREE.MathUtils.clamp(Number.parseFloat(value), 0, 1);
if (!Number.isFinite(next)) return;
clearActiveFlip();
readingProgress = next;
progressInput.value = readingProgress.toFixed(3);
progressValue.value = readingProgress.toFixed(2);
rebuildBook();
updateFlipControls();
}
function setPageCount(value) {
const next = snapPageCount(Number.parseFloat(value));
if (!Number.isFinite(next)) return;
clearActiveFlip();
pendingPageFlips = 0;
pageCount = next;
pageCountInput.value = String(pageCount);
pageCountValue.value = String(pageCount);
rebuildBook();
updateFlipControls();
}
function rebuildBook() {
clearGroup(book);
const coverDepth = 2.30;
const coverThickness = BOOK_PROFILE.coverThickness;
const pageWidth = 1.62;
const pageDepth = 2.24;
const bundleCount = Math.max(4, Math.round(pageCount / 10));
const spineWidth = Math.max(0.16, bundleCount * BOOK_PROFILE.bundleSpacing);
const lines = simulatePageLines(bundleCount, pageWidth, spineWidth);
lastLengthError = measureLineLengthError(lines, pageWidth);
lastSpacingError = measureStackSpacingError(lines);
lastBookModel = { coverDepth, pageWidth, pageDepth, bundleCount, spineWidth, lines };
addCoverAssembly(pageWidth, coverDepth, coverThickness, spineWidth);
addClothSpine(pageDepth, spineWidth);
addSimulatedStackBodies(lines, pageDepth);
addSimulatedPageLines(lines, pageDepth);
updateFlipControls();
}
function clearGroup(group) {
while (group.children.length) {
const child = group.children.pop();
child.geometry?.dispose();
if (Array.isArray(child.material)) {
child.material.forEach((material) => material.dispose?.());
}
}
}
function addCoverAssembly(pageWidth, depth, thickness, spineWidth) {
const cover = new THREE.Mesh(createCoverAssemblyGeometry(pageWidth, depth, thickness, spineWidth), materials.cover);
book.add(cover);
}
function createCoverAssemblyGeometry(pageWidth, depth, thickness, spineWidth) {
const overhang = 0.13;
const spineHalf = spineWidth * 0.5;
const hingeInset = 0.07;
const outerX = pageWidth + overhang;
const hingeX = spineHalf + hingeInset;
const outerTopY = BOOK_PROFILE.tableY + thickness;
const connectionTopY = BOOK_PROFILE.raisedHingeY;
const spineTopY = BOOK_PROFILE.tableY + thickness;
const section = [
{ x: -outerX, y: outerTopY },
{ x: -hingeX, y: connectionTopY },
{ x: -spineHalf, y: spineTopY },
{ x: spineHalf, y: spineTopY },
{ x: hingeX, y: connectionTopY },
{ x: outerX, y: outerTopY }
];
const positions = [];
const uvs = [];
const indices = [];
const frontTop = [];
const backTop = [];
const frontBottom = [];
const backBottom = [];
const push = (x, y, z, u, v) => {
const index = positions.length / 3;
positions.push(x, y, z);
uvs.push(u, v);
return index;
};
section.forEach((point, index) => {
const u = index / (section.length - 1);
frontTop[index] = push(point.x, point.y, depth * 0.5, u, 1);
backTop[index] = push(point.x, point.y, -depth * 0.5, u, 0);
frontBottom[index] = push(point.x, point.y - thickness, depth * 0.5, u, 1);
backBottom[index] = push(point.x, point.y - thickness, -depth * 0.5, u, 0);
});
for (let i = 0; i < section.length - 1; i += 1) {
indices.push(frontTop[i], backTop[i], frontTop[i + 1], frontTop[i + 1], backTop[i], backTop[i + 1]);
indices.push(frontBottom[i], frontBottom[i + 1], backBottom[i], frontBottom[i + 1], backBottom[i + 1], backBottom[i]);
indices.push(frontTop[i], frontTop[i + 1], frontBottom[i], frontTop[i + 1], frontBottom[i + 1], frontBottom[i]);
indices.push(backTop[i], backBottom[i], backTop[i + 1], backTop[i + 1], backBottom[i], backBottom[i + 1]);
}
const last = section.length - 1;
indices.push(frontTop[0], frontBottom[0], backTop[0], backTop[0], frontBottom[0], backBottom[0]);
indices.push(frontTop[last], backTop[last], frontBottom[last], backTop[last], backBottom[last], frontBottom[last]);
const geometry = new THREE.BufferGeometry();
geometry.setIndex(indices);
geometry.setAttribute('position', new THREE.Float32BufferAttribute(positions, 3));
geometry.setAttribute('uv', new THREE.Float32BufferAttribute(uvs, 2));
geometry.computeVertexNormals();
return geometry;
}
function addClothSpine(depth, spineWidth) {
const spine = new THREE.Mesh(createClothSpineGeometry(depth, spineWidth), materials.spine);
book.add(spine);
}
function createClothSpineGeometry(depth, spineWidth) {
const profile = [];
for (let i = 0; i <= 32; i += 1) {
const u = i / 32;
profile.push(spineCurvePoint(u, spineWidth));
}
const positions = [];
const indices = [];
const front = [];
const back = [];
const push = (point, z) => {
const index = positions.length / 3;
positions.push(point.x, point.y, z);
return index;
};
profile.forEach((point) => {
front.push(push(point, depth * 0.5 + 0.024));
back.push(push(point, -depth * 0.5 - 0.024));
});
for (let i = 0; i < profile.length - 1; i += 1) {
indices.push(front[i], back[i], front[i + 1]);
indices.push(front[i + 1], back[i], back[i + 1]);
}
const geometry = new THREE.BufferGeometry();
geometry.setIndex(indices);
geometry.setAttribute('position', new THREE.Float32BufferAttribute(positions, 3));
geometry.computeVertexNormals();
return geometry;
}
function spineCurvePoint(t, spineWidth) {
const radiusX = spineWidth * 0.42;
const radiusY = 0.018;
const baseY = BOOK_PROFILE.tableY + BOOK_PROFILE.coverThickness + 0.002;
const theta = Math.PI * (1 - THREE.MathUtils.clamp(t, 0, 1));
return {
t: THREE.MathUtils.clamp(t, 0, 1),
x: Math.cos(theta) * radiusX,
y: baseY + Math.sin(theta) * radiusY
};
}
function simulatePageLines(bundleCount, pageWidth, spineWidth) {
const lines = [];
const segments = 24;
const stepLength = pageWidth / segments;
const entries = [];
const spineSamples = sampleSpineByArc(bundleCount, spineWidth);
const leftLimit = Math.min(bundleCount - 2, Math.floor((bundleCount - 1) * readingProgress));
for (let index = 0; index < bundleCount; index += 1) {
const t = spineSamples[index].t;
const side = index <= leftLimit ? -1 : 1;
entries.push({ index, t, side });
}
[-1, 1].forEach((side) => {
const sideEntries = entries.filter((entry) => entry.side === side);
sideEntries.forEach((entry, rank) => {
entry.rank = rank;
entry.sideCount = sideEntries.length;
});
});
[-1, 1].forEach((side) => {
const sideEntries = entries
.filter((entry) => entry.side === side)
.sort((a, b) => side < 0 ? a.t - b.t : b.t - a.t);
if (!sideEntries.length) return;
let lowerLine = null;
sideEntries.forEach((entry, rank) => {
const anchor = spineCurvePoint(entry.t, spineWidth);
const target = restingTarget(side, pageWidth, rank, sideEntries.length);
const points = buildSupportSolvedLine(anchor, target, lowerLine, side, segments, stepLength, bundleCount);
const line = { index: entry.index, t: entry.t, side, anchor, points, endpoint: points[points.length - 1] };
lines.push(line);
lowerLine = line;
});
});
return lines;
}
function measureLineLengthError(lines, pageWidth) {
return lines.reduce((maxError, line) => {
let length = 0;
for (let i = 0; i < line.points.length - 1; i += 1) {
length += Math.hypot(line.points[i + 1].x - line.points[i].x, line.points[i + 1].y - line.points[i].y);
}
return Math.max(maxError, Math.abs(length - pageWidth));
}, 0);
}
function measureStackSpacingError(lines) {
let maxViolation = 0;
[-1, 1].forEach((side) => {
const sideLines = lines
.filter((line) => line.side === side)
.sort((a, b) => side < 0 ? a.t - b.t : b.t - a.t);
for (let row = 1; row < sideLines.length; row += 1) {
const lower = sideLines[row - 1];
const upper = sideLines[row];
for (let col = 1; col < upper.points.length; col += 1) {
const closest = closestPointOnPolyline(upper.points[col], lower.points);
const distance = Math.hypot(upper.points[col].x - closest.x, upper.points[col].y - closest.y);
maxViolation = Math.max(maxViolation, Math.max(0, BOOK_PROFILE.bundleSpacing - distance));
}
}
});
return maxViolation;
}
function sampleSpineByArc(count, spineWidth) {
const samples = [];
const steps = 240;
let length = 0;
let previous = spineCurvePoint(0, spineWidth);
samples.push({ point: previous, length });
for (let i = 1; i <= steps; i += 1) {
const t = i / steps;
const point = spineCurvePoint(t, spineWidth);
length += Math.hypot(point.x - previous.x, point.y - previous.y);
samples.push({ point, length });
previous = point;
}
const points = [];
for (let i = 0; i < count; i += 1) {
const target = count === 1 ? length * 0.5 : length * (i / (count - 1));
const found = samples.findIndex((sample) => sample.length >= target);
if (found <= 0) {
points.push(samples[0].point);
continue;
}
const before = samples[found - 1];
const after = samples[found];
const span = after.length - before.length || 1;
const t = THREE.MathUtils.lerp(before.point.t, after.point.t, (target - before.length) / span);
points.push(spineCurvePoint(t, spineWidth));
}
return points;
}
function initialPageLine(anchor, target, segments) {
const points = [];
for (let i = 0; i <= segments; i += 1) {
const u = i / segments;
const sag = 0.04 * Math.sin(Math.PI * u);
points.push({
x: THREE.MathUtils.lerp(anchor.x, target.x, u),
y: THREE.MathUtils.lerp(anchor.y, target.y, u) - sag * u
});
}
return points;
}
function restingTarget(side, pageWidth, rank, sideCount) {
const local = sideCount <= 1 ? 0 : rank / (sideCount - 1);
const foreCurve = 0.11 * Math.sin(Math.PI * local);
const x = side * (pageWidth - foreCurve);
const y = BOOK_PROFILE.coverThickness + BOOK_PROFILE.paperContactOffset + rank * BOOK_PROFILE.bundleSpacing + 0.002 * Math.sin(Math.PI * local);
return { x, y };
}
function buildSupportSolvedLine(anchor, target, lowerLine, side, segments, stepLength, bundleCount) {
const points = [{ x: anchor.x, y: anchor.y }];
let tangent = coverTangentAtX(anchor.x, side);
for (let index = 1; index <= segments; index += 1) {
const u = index / segments;
const supportTangent = lowerLine ? lineTangentAt(lowerLine.points, index) : coverTangentAtX(points[index - 1].x, side);
const point = chooseClosestSupportedPoint(points[index - 1], tangent, supportTangent, target, lowerLine, index, side, stepLength, bundleCount, u);
points.push(point);
tangent = normalizedVector(point.x - points[index - 1].x, point.y - points[index - 1].y);
}
return points;
}
function chooseClosestSupportedPoint(previous, tangent, supportTangent, target, lowerLine, index, side, stepLength, bundleCount, u) {
const blendTangent = normalizedVector(tangent.x + supportTangent.x * 2, tangent.y + supportTangent.y * 2);
const angleHint = Math.atan2(blendTangent.y, blendTangent.x);
let best = null;
let fallback = null;
for (let sample = 0; sample < 720; sample += 1) {
const angle = sample / 720 * Math.PI * 2;
const candidate = {
x: previous.x + Math.cos(angle) * stepLength,
y: previous.y + Math.sin(angle) * stepLength
};
const score = scoreSupportedPoint(candidate, previous, tangent, supportTangent, angle, angleHint, target, lowerLine, index, side, bundleCount, u);
if (best === null || score < best.score) best = { point: candidate, score };
const fallbackScore = scoreSupportedPoint(candidate, previous, tangent, supportTangent, angle, angleHint, target, lowerLine, index, side, bundleCount, u, true);
if (fallback === null || fallbackScore < fallback.score) fallback = { point: candidate, score: fallbackScore };
}
return Number.isFinite(best?.score) ? best.point : fallback.point;
}
function scoreSupportedPoint(candidate, previous, tangent, supportTangent, angle, angleHint, target, lowerLine, index, side, bundleCount, u, allowViolation = false) {
const backward = Math.max(0, side * (previous.x - candidate.x));
if (!allowViolation && backward > 0.00001) return Number.POSITIVE_INFINITY;
let supportError;
let supportViolation = 0;
if (lowerLine) {
const closest = closestPointOnPolyline(candidate, lowerLine.points);
const closestDistance = Math.hypot(candidate.x - closest.x, candidate.y - closest.y);
supportViolation = Math.max(0, BOOK_PROFILE.bundleSpacing - closestDistance) + Math.max(0, closest.y - candidate.y);
if (!allowViolation && supportViolation > 0.00001) return Number.POSITIVE_INFINITY;
supportError = closestDistance - BOOK_PROFILE.bundleSpacing;
} else {
const floor = coverTopYAtX(candidate.x) + coverClearance(bundleCount);
supportViolation = Math.max(0, floor - candidate.y);
if (!allowViolation && supportViolation > 0.00001) return Number.POSITIVE_INFINITY;
supportError = candidate.y - floor;
}
const candidateTangent = normalizedVector(candidate.x - previous.x, candidate.y - previous.y);
const bend = 1 - Math.max(-1, Math.min(1, candidateTangent.x * tangent.x + candidateTangent.y * tangent.y));
const supportAlignment = 1 - Math.max(-1, Math.min(1, candidateTangent.x * supportTangent.x + candidateTangent.y * supportTangent.y));
const angleDelta = Math.abs(Math.atan2(Math.sin(angle - angleHint), Math.cos(angle - angleHint)));
const outwardTarget = Math.max(0, side * (target.x - candidate.x));
const targetHeight = Math.abs(candidate.y - target.y);
return Math.abs(supportError) * 1200 + supportViolation * 100000 + backward * 100000 + supportAlignment * 0.85 + bend * 0.22 + angleDelta * 0.04 + outwardTarget * 0.01 + targetHeight * 0.006;
}
function closestPointOnPolyline(point, polyline) {
let best = polyline[0];
let bestDistance = Number.POSITIVE_INFINITY;
for (let i = 0; i < polyline.length - 1; i += 1) {
const candidate = closestPointOnSegment(point, polyline[i], polyline[i + 1]);
const distance = Math.hypot(point.x - candidate.x, point.y - candidate.y);
if (distance < bestDistance) {
best = candidate;
bestDistance = distance;
}
}
return best;
}
function closestPointOnSegment(point, a, b) {
const dx = b.x - a.x;
const dy = b.y - a.y;
const lengthSquared = dx * dx + dy * dy || 0.0001;
const t = THREE.MathUtils.clamp(((point.x - a.x) * dx + (point.y - a.y) * dy) / lengthSquared, 0, 1);
return {
x: a.x + dx * t,
y: a.y + dy * t
};
}
function coverTangentAtX(x, side) {
const delta = 0.002;
const y0 = coverTopYAtX(x - delta);
const y1 = coverTopYAtX(x + delta);
return normalizedVector(side * delta * 2, y1 - y0);
}
function lineTangentAt(points, index) {
const previous = points[Math.max(0, index - 1)];
const next = points[Math.min(points.length - 1, index + 1)];
return normalizedVector(next.x - previous.x, next.y - previous.y);
}
function normalizedVector(x, y) {
const length = Math.hypot(x, y) || 0.0001;
return { x: x / length, y: y / length };
}
function relaxPageLine(points, anchor, stepLength, side, local, bundleCount) {
const gravity = 0.00072;
const stackPressure = 0.0011 * (1 - local);
const bendStrength = 0.52;
const iterations = 72;
for (let iteration = 0; iteration < iterations; iteration += 1) {
points[0].x = anchor.x;
points[0].y = anchor.y;
for (let i = 1; i < points.length; i += 1) {
const u = i / (points.length - 1);
points[i].y -= gravity * u + stackPressure * u * u;
}
applyBendingResistance(points, bendStrength);
for (let pass = 0; pass < 3; pass += 1) {
points[0].x = anchor.x;
points[0].y = anchor.y;
enforceLineLength(points, anchor, stepLength, 3);
keepPageAboveCover(points, side, bundleCount);
}
}
}
function applyBendingResistance(points, strength) {
const updates = points.map((point) => ({ x: point.x, y: point.y }));
for (let i = 1; i < points.length - 1; i += 1) {
const previous = points[i - 1];
const current = points[i];
const next = points[i + 1];
updates[i].x += (previous.x + next.x - current.x * 2) * strength;
updates[i].y += (previous.y + next.y - current.y * 2) * strength;
}
for (let i = 1; i < points.length - 1; i += 1) {
points[i].x = updates[i].x;
points[i].y = updates[i].y;
}
}
function enforceLineLength(points, anchor, stepLength, passes) {
for (let pass = 0; pass < passes; pass += 1) {
points[0].x = anchor.x;
points[0].y = anchor.y;
for (let i = 0; i < points.length - 1; i += 1) {
constrainSegment(points[i], points[i + 1], stepLength, i === 0);
}
for (let i = points.length - 2; i >= 0; i -= 1) {
constrainSegment(points[i], points[i + 1], stepLength, i === 0);
}
}
}
function constrainSegment(a, b, length, anchorA) {
const dx = b.x - a.x;
const dy = b.y - a.y;
const distance = Math.hypot(dx, dy) || 0.0001;
const correction = (distance - length) / distance;
if (anchorA) {
b.x -= dx * correction;
b.y -= dy * correction;
return;
}
a.x += dx * correction * 0.5;
a.y += dy * correction * 0.5;
b.x -= dx * correction * 0.5;
b.y -= dy * correction * 0.5;
}
function enforceForwardLineLength(points, anchor, stepLength) {
points[0].x = anchor.x;
points[0].y = anchor.y;
for (let i = 1; i < points.length; i += 1) {
const previous = points[i - 1];
const current = points[i];
const dx = current.x - previous.x;
const dy = current.y - previous.y;
const distance = Math.hypot(dx, dy) || 0.0001;
current.x = previous.x + dx / distance * stepLength;
current.y = previous.y + dy / distance * stepLength;
}
}
function keepPageAboveCover(points, side, bundleCount) {
for (let i = 1; i < points.length; i += 1) {
points[i].y = Math.max(points[i].y, coverTopYAtX(points[i].x) + coverClearance(bundleCount));
points[i].x = side < 0 ? Math.min(points[i].x, -0.01) : Math.max(points[i].x, 0.01);
}
}
function coverClearance(bundleCount) {
return BOOK_PROFILE.paperContactOffset + 0.0002 * bundleCount;
}
function enforceStackConstraints(lines, stepLength, bundleCount) {
const iterations = 44;
[-1, 1].forEach((side) => {
const sideLines = lines
.filter((line) => line.side === side)
.sort((a, b) => side < 0 ? a.t - b.t : b.t - a.t);
for (let iteration = 0; iteration < iterations; iteration += 1) {
sideLines.forEach((line) => {
line.points[0].x = line.anchor.x;
line.points[0].y = line.anchor.y;
applyBendingResistance(line.points, 0.22);
enforceLineLength(line.points, line.anchor, stepLength, 3);
keepPageAboveCover(line.points, side, bundleCount);
});
for (let row = 1; row < sideLines.length; row += 1) {
const lower = sideLines[row - 1];
const upper = sideLines[row];
for (let col = 1; col < upper.points.length; col += 1) {
const normal = upwardNormalAt(lower.points, col);
const targetX = lower.points[col].x + normal.x * BOOK_PROFILE.bundleSpacing;
const targetY = lower.points[col].y + normal.y * BOOK_PROFILE.bundleSpacing;
upper.points[col].x = THREE.MathUtils.lerp(upper.points[col].x, targetX, 0.28);
upper.points[col].y = Math.max(upper.points[col].y, THREE.MathUtils.lerp(upper.points[col].y, targetY, 0.42));
}
upper.points[0].x = upper.anchor.x;
upper.points[0].y = upper.anchor.y;
applyBendingResistance(upper.points, 0.2);
enforceLineLength(upper.points, upper.anchor, stepLength, 3);
keepPageAboveCover(upper.points, side, bundleCount);
}
}
sideLines.forEach((line) => {
applyBendingResistance(line.points, 0.32);
enforceLineLength(line.points, line.anchor, stepLength, 10);
keepPageAboveCover(line.points, side, bundleCount);
enforceLineLength(line.points, line.anchor, stepLength, 6);
});
sideLines.forEach((line) => {
line.endpoint = line.points[line.points.length - 1];
});
});
}
function offsetPageLine(basePoints, anchor, distance) {
return basePoints.map((point, index) => {
if (index === 0) return { x: anchor.x, y: anchor.y };
const normal = upwardNormalAt(basePoints, index);
return {
x: point.x + normal.x * distance,
y: point.y + normal.y * distance
};
});
}
function upwardNormalAt(points, index) {
const previous = points[Math.max(0, index - 1)];
const next = points[Math.min(points.length - 1, index + 1)];
const dx = next.x - previous.x;
const dy = next.y - previous.y;
const length = Math.hypot(dx, dy) || 0.0001;
let nx = -dy / length;
let ny = dx / length;
if (ny < 0) {
nx = -nx;
ny = -ny;
}
return { x: nx, y: ny };
}
function coverTopYAtX(x) {
const ax = Math.abs(x);
const spineHalf = currentSpineHalf();
const hingeX = spineHalf + 0.07;
const outerX = 1.62 + 0.055;
if (ax <= spineHalf) return BOOK_PROFILE.coverThickness;
if (ax <= hingeX) {
const t = (ax - spineHalf) / (hingeX - spineHalf);
return THREE.MathUtils.lerp(BOOK_PROFILE.coverThickness, BOOK_PROFILE.raisedHingeY, t);
}
const t = THREE.MathUtils.clamp((ax - hingeX) / (outerX - hingeX), 0, 1);
return THREE.MathUtils.lerp(BOOK_PROFILE.raisedHingeY, BOOK_PROFILE.coverThickness, t);
}
function currentSpineHalf() {
return Math.max(0.16, Math.round(pageCount / 10) * BOOK_PROFILE.bundleSpacing) * 0.5;
}
function addSimulatedPageLines(lines, depth) {
const leftMaterial = new THREE.LineBasicMaterial({ color: 0x8f7750, transparent: true, opacity: 0.72 });
const rightMaterial = new THREE.LineBasicMaterial({ color: 0x9a8058, transparent: true, opacity: 0.72 });
const z = depth * 0.5 + 0.006;
lines.forEach((line) => {
const points = line.points.map((point) => new THREE.Vector3(point.x, point.y, z));
book.add(new THREE.Line(new THREE.BufferGeometry().setFromPoints(points), line.side < 0 ? leftMaterial : rightMaterial));
});
}
function addSimulatedStackBodies(lines, depth) {
[-1, 1].forEach((side) => {
const sideLines = lines.filter((line) => line.side === side);
if (!sideLines.length) return;
const material = side < 0 ? materials.pagesLeft : materials.pagesRight;
const bodyLines = sideLines.length === 1 ? createSinglePageBodyLines(sideLines[0]) : sideLines;
book.add(new THREE.Mesh(createLoftedLineBody(bodyLines, depth), material));
book.add(new THREE.Line(createEndpointPolyline(bodyLines, depth), new THREE.LineBasicMaterial({ color: 0xb99a68, transparent: true, opacity: 0.62 })));
});
}
function createSinglePageBodyLines(line) {
const bundleCount = Math.max(4, Math.round(pageCount / 10));
const supportPoints = line.points.map((point) => ({
x: point.x,
y: Math.max(coverTopYAtX(point.x) + coverClearance(bundleCount) + BOOK_PROFILE.singlePageCoverGap, point.y - BOOK_PROFILE.bundleSpacing)
}));
return [
{ ...line, points: supportPoints, endpoint: supportPoints[supportPoints.length - 1] },
line
];
}
function createLoftedLineBody(lines, depth) {
const positions = [];
const indices = [];
const smoothLines = lines.map((line) => line.points);
const push = (point, z) => {
const index = positions.length / 3;
positions.push(point.x, point.y, z);
return index;
};
const front = smoothLines.map((points) => points.map((point) => push(point, depth * 0.5)));
const back = smoothLines.map((points) => points.map((point) => push(point, -depth * 0.5)));
for (let row = 0; row < smoothLines.length - 1; row += 1) {
for (let col = 0; col < smoothLines[row].length - 1; col += 1) {
indices.push(front[row][col], front[row + 1][col], front[row][col + 1]);
indices.push(front[row][col + 1], front[row + 1][col], front[row + 1][col + 1]);
indices.push(back[row][col], back[row][col + 1], back[row + 1][col]);
indices.push(back[row][col + 1], back[row + 1][col + 1], back[row + 1][col]);
}
}
for (let row = 0; row < smoothLines.length - 1; row += 1) {
const last = smoothLines[row].length - 1;
indices.push(front[row][last], front[row + 1][last], back[row][last]);
indices.push(front[row + 1][last], back[row + 1][last], back[row][last]);
}
for (let col = 0; col < smoothLines[0].length - 1; col += 1) {
const topRow = smoothLines.length - 1;
indices.push(front[topRow][col], back[topRow][col], front[topRow][col + 1]);
indices.push(front[topRow][col + 1], back[topRow][col], back[topRow][col + 1]);
}
const geometry = new THREE.BufferGeometry();
geometry.setIndex(indices);
geometry.setAttribute('position', new THREE.Float32BufferAttribute(positions, 3));
geometry.computeVertexNormals();
return geometry;
}
function createEndpointPolyline(lines, depth) {
const points = lines.map((line) => new THREE.Vector3(line.endpoint.x, line.endpoint.y, depth * 0.5 + 0.008));
return new THREE.BufferGeometry().setFromPoints(points);
}
function startPageFlip(direction) {
if (activeFlip || !lastBookModel || !canPageFlip(direction)) return false;
const sourceSide = direction > 0 ? 1 : -1;
const sourceLine = topVisibleLine(sourceSide);
const destinationLine = topVisibleLine(-sourceSide);
if (!sourceLine || !destinationLine) return false;
activeFlip = {
direction,
sourceLine,
destinationLine,
startTime: performance.now(),
duration: 1800
};
updateFlipControls();
updateActiveFlip(activeFlip.startTime);
return true;
}
function canPageFlip(direction) {
if (!lastBookModel) return false;
if (direction > 0) return readingProgress < 1;
return readingProgress > 0;
}
function topVisibleLine(side) {
const sideLines = lastBookModel.lines
.filter((line) => line.side === side)
.sort((a, b) => side < 0 ? a.t - b.t : b.t - a.t);
return sideLines[sideLines.length - 1] ?? null;
}
function updateActiveFlip(now) {
if (!activeFlip || !lastBookModel) return;
const elapsed = (now - activeFlip.startTime) / activeFlip.duration;
const t = THREE.MathUtils.clamp(elapsed, 0, 1);
const surface = buildFlippingPageSurface(activeFlip.sourceLine, activeFlip.destinationLine, activeFlip.direction, easeInOutCubic(t));
setActivePageGeometry(surface);
if (t < 1) return;
finishActiveFlip();
}
function buildFlippingPageSurface(sourceLine, destinationLine, direction, t) {
const widthSegments = sourceLine.points.length - 1;
const depthSegments = 18;
const zFront = lastBookModel.pageDepth * 0.5 + 0.018;
const zBack = -lastBookModel.pageDepth * 0.5 - 0.018;
if (t <= 0) return createRestingPageSurface(sourceLine.points, depthSegments, zFront, zBack);
if (t >= 1) return createRestingPageSurface(destinationLine.points, depthSegments, zFront, zBack);
const anchorT = THREE.MathUtils.lerp(sourceLine.t, destinationLine.t, t);
const anchor = spineCurvePoint(anchorT, lastBookModel.spineWidth);
const sourceSide = direction > 0 ? 1 : -1;
const startAngle = sourceSide > 0 ? 0 : Math.PI;
const baseAngle = startAngle + direction * Math.PI * t;
const lift = Math.sin(Math.PI * t);
const curlStrength = direction * 0.48 * lift;
const surface = [];
for (let widthIndex = 0; widthIndex <= widthSegments; widthIndex += 1) {
const u = widthIndex / widthSegments;
const radius = lastBookModel.pageWidth * u;
const row = [];
for (let depthIndex = 0; depthIndex <= depthSegments; depthIndex += 1) {
const v = depthIndex / depthSegments;
const z = THREE.MathUtils.lerp(zFront, zBack, v);
const depthWave = (v - 0.5) * 0.22 * lift * (0.15 + u * 0.85);
const curl = curlStrength * Math.sin(Math.PI * u) + direction * depthWave;
const angle = baseAngle + curl;
const stackPoint = interpolatePagePoint(sourceLine.points, destinationLine.points, widthIndex, t);
const relaxedY = THREE.MathUtils.lerp(stackPoint.y, anchor.y + Math.sin(angle) * radius, lift);
const point = {
x: anchor.x + Math.cos(angle) * radius,
y: relaxedY + 0.055 * lift * Math.sin(Math.PI * u),
z
};
keepFlippingSurfacePointAboveStacks(point, lift);
row.push(point);
}
surface.push(row);
}
return surface;
}
function createRestingPageSurface(points, depthSegments, zFront, zBack) {
return points.map((point) => {
const row = [];
for (let depthIndex = 0; depthIndex <= depthSegments; depthIndex += 1) {
row.push({
x: point.x,
y: point.y,
z: THREE.MathUtils.lerp(zFront, zBack, depthIndex / depthSegments)
});
}
return row;
});
}
function interpolatePagePoint(sourcePoints, destinationPoints, index, t) {
const source = sourcePoints[index];
const destination = destinationPoints[index];
return {
x: THREE.MathUtils.lerp(source.x, destination.x, t),
y: THREE.MathUtils.lerp(source.y, destination.y, t)
};
}
function keepFlippingSurfacePointAboveStacks(point, lift) {
const envelopeY = stackEnvelopeYAtX(point.x);
if (envelopeY === null) return;
const clearance = 0.016 + lift * 0.045;
point.y = Math.max(point.y, envelopeY + clearance);
}
function keepFlippingPageAboveStacks(points, lift) {
for (let index = 1; index < points.length; index += 1) {
const u = index / (points.length - 1);
const envelopeY = stackEnvelopeYAtX(points[index].x);
if (envelopeY === null) continue;
const clearance = 0.018 + lift * (0.05 + 0.05 * Math.sin(Math.PI * u));
points[index].y = Math.max(points[index].y, envelopeY + clearance);
}
}
function stackEnvelopeYAtX(x) {
let envelope = null;
lastBookModel.lines.forEach((line) => {
const y = lineYAtX(line.points, x);
if (y === null) return;
envelope = envelope === null ? y : Math.max(envelope, y);
});
return envelope;
}
function lineYAtX(points, x) {
let y = null;
for (let index = 0; index < points.length - 1; index += 1) {
const a = points[index];
const b = points[index + 1];
const minX = Math.min(a.x, b.x) - 0.00001;
const maxX = Math.max(a.x, b.x) + 0.00001;
if (x < minX || x > maxX) continue;
const span = b.x - a.x;
const segmentY = Math.abs(span) < 0.00001
? Math.max(a.y, b.y)
: THREE.MathUtils.lerp(a.y, b.y, (x - a.x) / span);
y = y === null ? segmentY : Math.max(y, segmentY);
}
return y;
}
function setActivePageGeometry(surface) {
const geometry = createFlippingPageGeometry(surface);
if (!activeFlipMesh) {
activeFlipMesh = new THREE.Mesh(geometry, materials.flippingPage);
book.add(activeFlipMesh);
return;
}
activeFlipMesh.geometry.dispose();
activeFlipMesh.geometry = geometry;
}
function createFlippingPageGeometry(surface) {
const positions = [];
const indices = [];
const topGrid = [];
const bottomGrid = [];
const pageThickness = 0.006;
const widthSegments = surface.length - 1;
const depthSegments = surface[0].length - 1;
const push = (point, yOffset) => {
const index = positions.length / 3;
positions.push(point.x, point.y + yOffset, point.z);
return index;
};
surface.forEach((rowPoints) => {
const topRow = [];
const bottomRow = [];
rowPoints.forEach((point) => {
topRow.push(push(point, pageThickness));
bottomRow.push(push(point, 0));
});
topGrid.push(topRow);
bottomGrid.push(bottomRow);
});
for (let index = 0; index < widthSegments; index += 1) {
for (let zIndex = 0; zIndex < depthSegments; zIndex += 1) {
const a = topGrid[index][zIndex];
const b = topGrid[index + 1][zIndex];
const c = topGrid[index][zIndex + 1];
const d = topGrid[index + 1][zIndex + 1];
const bottomA = bottomGrid[index][zIndex];
const bottomB = bottomGrid[index + 1][zIndex];
const bottomC = bottomGrid[index][zIndex + 1];
const bottomD = bottomGrid[index + 1][zIndex + 1];
indices.push(a, c, b);
indices.push(b, c, d);
indices.push(bottomA, bottomB, bottomC);
indices.push(bottomB, bottomD, bottomC);
}
}
for (let index = 0; index < widthSegments; index += 1) {
addWall(topGrid[index][0], topGrid[index + 1][0], bottomGrid[index][0], bottomGrid[index + 1][0]);
addWall(topGrid[index][depthSegments], topGrid[index + 1][depthSegments], bottomGrid[index][depthSegments], bottomGrid[index + 1][depthSegments]);
}
for (let zIndex = 0; zIndex < depthSegments; zIndex += 1) {
addWall(topGrid[0][zIndex], topGrid[0][zIndex + 1], bottomGrid[0][zIndex], bottomGrid[0][zIndex + 1]);
addWall(topGrid[widthSegments][zIndex], topGrid[widthSegments][zIndex + 1], bottomGrid[widthSegments][zIndex], bottomGrid[widthSegments][zIndex + 1]);
}
const geometry = new THREE.BufferGeometry();
geometry.setIndex(indices);
geometry.setAttribute('position', new THREE.Float32BufferAttribute(positions, 3));
geometry.computeVertexNormals();
return geometry;
function addWall(topA, topB, bottomA, bottomB) {
indices.push(topA, bottomA, topB);
indices.push(topB, bottomA, bottomB);
}
}
function finishActiveFlip() {
const direction = activeFlip.direction;
clearActiveFlip();
pendingPageFlips += direction;
if (Math.abs(pendingPageFlips) >= 10) {
const commitDirection = Math.sign(pendingPageFlips);
pendingPageFlips -= commitDirection * 10;
const step = 1 / (lastBookModel.bundleCount - 1);
setReadingProgress(readingProgress + commitDirection * step);
return;
}
updateFlipControls();
}
function clearActiveFlip() {
activeFlip = null;
if (!activeFlipMesh) return;
book.remove(activeFlipMesh);
activeFlipMesh.geometry.dispose();
activeFlipMesh = null;
}
function updateFlipControls() {
flipBackwardButton.disabled = Boolean(activeFlip) || !canPageFlip(-1);
flipForwardButton.disabled = Boolean(activeFlip) || !canPageFlip(1);
flipCountValue.textContent = `${Math.abs(pendingPageFlips)} / 10`;
}
function easeInOutCubic(t) {
return t < 0.5 ? 4 * t * t * t : 1 - Math.pow(-2 * t + 2, 3) * 0.5;
}
function resize() {
const width = window.innerWidth;
const height = window.innerHeight;
renderer.setSize(width, height, false);
camera.aspect = width / height;
camera.updateProjectionMatrix();
}
function animate() {
requestAnimationFrame(animate);
if (urlParams.get('animate') === '1') {
const t = performance.now() * 0.00035;
setReadingProgress(0.5 + Math.sin(t) * 0.48);
}
updateActiveFlip(performance.now());
controls.update();
renderer.render(scene, camera);
}