playcanvas
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PlayCanvas WebGL game engine
536 lines (533 loc) • 26.4 kB
JavaScript
import { Debug } from '../../core/debug.js';
import { Mat4 } from '../../core/math/mat4.js';
import { Vec2 } from '../../core/math/vec2.js';
import { Vec3 } from '../../core/math/vec3.js';
import { BoundingBox } from '../../core/shape/bounding-box.js';
import { Color } from '../../core/math/color.js';
import { GSplatPlacement } from './gsplat-placement.js';
/**
* @import { GraphNode } from '../graph-node.js'
* @import { GSplatOctree } from './gsplat-octree.js'
* @import { GSplatAssetLoaderBase } from './gsplat-asset-loader-base.js'
* @import { Scene } from '../scene.js'
*/ const _invWorldMat = new Mat4();
const _localCameraPos = new Vec3();
const _localCameraFwd = new Vec3();
const _dirToNode = new Vec3();
const _tempCompletedUrls = [];
const _tempDebugAabb = new BoundingBox();
// Color instances used by debug wireframe rendering for LOD visualization
const _lodColors = [
new Color(1, 0, 0),
new Color(0, 1, 0),
new Color(0, 0, 1),
new Color(1, 1, 0),
new Color(1, 0, 1)
];
class GSplatOctreeInstance {
/**
* @param {GSplatOctree} octree - The octree.
* @param {GSplatPlacement} placement - The placement.
* @param {GSplatAssetLoaderBase} assetLoader - The asset loader.
*/ constructor(octree, placement, assetLoader){
/** @type {Set<GSplatPlacement>} */ this.activePlacements = new Set();
/** @type {boolean} */ this.dirtyModifiedPlacements = false;
/**
* Set of pending file loads (file indices).
* @type {Set<number>}
*/ this.pending = new Set();
/**
* Map of nodeIndex -> { oldFileIndex, newFileIndex } that needs to be decremented when the
* new LOD resource loads. This ensures we decrement even if the node switches LOD again
* before the new resource arrives.
*
* @type {Map<number, { oldFileIndex: number, newFileIndex: number }>}
*/ this.pendingDecrements = new Map();
/**
* Files that became unused by this instance this update. Each entry represents a single decRef.
*
* @type {Set<number>}
*/ this.removedCandidates = new Set();
/**
* Previous node position at which LOD was last updated. This is used to determine if LOD needs
* to be updated as the octree splat moves.
*
* @type {Vec3}
*/ this.previousPosition = new Vec3();
/**
* Set when a resource has completed loading and LOD should be re-evaluated.
*
* @type {boolean}
*/ this.needsLodUpdate = false;
/**
* Tracks prefetched file indices that are being loaded without active placements.
* When any completes, we trigger LOD re-evaluation to allow promotion.
*
* @type {Set<number>}
*/ this.prefetchPending = new Set();
/**
* Tracks invisible->visible pending adds per node: nodeIndex -> fileIndex.
* Ensures only a single pending placement exists for a node while it's not yet displayed.
* @type {Map<number, number>}
*/ this.pendingVisibleAdds = new Map();
this.octree = octree;
this.placement = placement;
this.assetLoader = assetLoader;
// Initialize nodeLods array with all nodes set to -1 (not visible)
this.nodeLods = new Int32Array(octree.nodes.length);
this.nodeLods.fill(-1);
// Initialize file placements array
const numFiles = octree.files.length;
this.filePlacements = new Array(numFiles).fill(null);
}
/**
* Destroys this octree instance and clears internal references.
*/ destroy() {
this.pending.clear();
this.pendingDecrements.clear();
this.filePlacements.length = 0;
}
/**
* Returns the file indices currently referenced by this instance that should be decremented
* when the instance is destroyed.
*
* @returns {number[]} Array of file indices to decRef.
*/ getFileDecrements() {
const toRelease = [];
for(let i = 0; i < this.filePlacements.length; i++){
if (this.filePlacements[i]) {
toRelease.push(i);
}
}
return toRelease;
}
/**
* Calculate LOD index for a specific node using pre-calculated local camera position.
* @param {Vec3} localCameraPosition - The camera position in local space.
* @param {Vec3} localCameraForward - The camera forward direction in local space (normalized).
* @param {number} nodeIndex - The node index.
* @param {number} maxLod - The maximum LOD index (lodLevels - 1).
* @param {number[]} lodDistances - Array of distance thresholds per LOD.
* @param {number} lodBehindPenalty - Multiplier for behind-camera distance. 1 disables penalty.
* @returns {number} The LOD index for this node, or -1 if node should not be rendered.
*/ calculateNodeLod(localCameraPosition, localCameraForward, nodeIndex, maxLod, lodDistances, lodBehindPenalty) {
const node = this.octree.nodes[nodeIndex];
// Calculate distance in local space
_dirToNode.copy(node.bounds.center).sub(localCameraPosition);
let distance = _dirToNode.length();
// Apply angular-based multiplier for nodes behind the camera when enabled
if (lodBehindPenalty > 1 && distance > 0.01) {
// dot using unnormalized direction to avoid extra normalize; divide by distance
const dotOverDistance = localCameraForward.dot(_dirToNode) / distance;
// Only apply penalty when behind the camera (dot < 0)
if (dotOverDistance < 0) {
const t = -dotOverDistance; // 0 .. 1 for front -> directly behind
const factor = 1 + t * (lodBehindPenalty - 1);
distance *= factor;
}
}
// Find appropriate LOD based on distance and available LOD levels
for(let lod = 0; lod < maxLod; lod++){
if (distance < lodDistances[lod]) {
return lod;
}
}
// If distance is greater than all thresholds, use the highest available LOD
return maxLod;
// return -1 for past far plane
}
/**
* Selects desired LOD index for a node using the underfill strategy. When underfill is enabled,
* it prefers already-loaded LODs within [optimalLodIndex .. optimalLodIndex + lodUnderfillLimit].
* If none are loaded, it selects the coarsest available LOD within the range.
*
* @param {import('./gsplat-octree-node.js').GSplatOctreeNode} node - The octree node.
* @param {number} optimalLodIndex - Optimal LOD index based on camera/distance.
* @param {number} maxLod - Maximum LOD index.
* @param {number} lodUnderfillLimit - Allowed coarse range above optimal.
* @returns {number} Desired LOD index to display.
*/ selectDesiredLodIndex(node, optimalLodIndex, maxLod, lodUnderfillLimit) {
if (lodUnderfillLimit > 0) {
const allowedMaxCoarseLod = Math.min(maxLod, optimalLodIndex + lodUnderfillLimit);
// prefer highest quality already-loaded within the allowed range
for(let lod = optimalLodIndex; lod <= allowedMaxCoarseLod; lod++){
const fi = node.lods[lod].fileIndex;
if (fi !== -1 && this.octree.getFileResource(fi)) {
return lod;
}
}
// fallback: choose the coarsest available within the range
for(let lod = allowedMaxCoarseLod; lod >= optimalLodIndex; lod--){
const fi = node.lods[lod].fileIndex;
if (fi !== -1) {
return lod;
}
}
}
return optimalLodIndex;
}
/**
* Prefetch only the next-better LOD toward optimal. This stages loading in steps across all
* nodes, avoiding intermixing requests before coarse is present.
*
* @param {import('./gsplat-octree-node.js').GSplatOctreeNode} node - The octree node.
* @param {number} desiredLodIndex - Currently selected LOD for display (may be coarser than optimal).
* @param {number} optimalLodIndex - Target optimal LOD.
*/ prefetchNextLod(node, desiredLodIndex, optimalLodIndex) {
if (desiredLodIndex === -1 || optimalLodIndex === -1) return;
// If we're already at optimal but it's not loaded yet, request it
if (desiredLodIndex === optimalLodIndex) {
const fi = node.lods[optimalLodIndex].fileIndex;
if (fi !== -1) {
this.octree.ensureFileResource(fi, this.assetLoader);
if (!this.octree.getFileResource(fi)) {
this.prefetchPending.add(fi);
}
}
return;
}
// Step one level finer toward optimal
const targetLod = Math.max(optimalLodIndex, desiredLodIndex - 1);
// Find first valid fileIndex between targetLod..optimalLodIndex
for(let lod = targetLod; lod >= optimalLodIndex; lod--){
const fi = node.lods[lod].fileIndex;
if (fi !== -1) {
this.octree.ensureFileResource(fi, this.assetLoader);
if (!this.octree.getFileResource(fi)) {
this.prefetchPending.add(fi);
}
break;
}
}
}
/**
* Updates the octree instance when LOD needs to be updated.
*
* @param {GraphNode} cameraNode - The camera node.
* @param {import('./gsplat-params.js').GSplatParams} params - Global gsplat parameters.
*/ updateLod(cameraNode, params) {
// transform camera position to octree local space
const worldCameraPosition = cameraNode.getPosition();
const octreeWorldTransform = this.placement.node.getWorldTransform();
_invWorldMat.copy(octreeWorldTransform).invert();
const localCameraPosition = _invWorldMat.transformPoint(worldCameraPosition, _localCameraPos);
const worldCameraForward = cameraNode.forward;
const localCameraForward = _invWorldMat.transformVector(worldCameraForward, _localCameraFwd).normalize();
// calculate max LOD once for all nodes
const maxLod = this.octree.lodLevels - 1;
const lodDistances = this.placement.lodDistances || [
5,
10,
15,
20,
25
];
// parameters
const { lodBehindPenalty, lodRangeMin, lodRangeMax, lodUnderfillLimit = 0 } = params;
// Clamp configured LOD range to valid bounds [0, maxLod] and ensure min <= max
const rangeMin = Math.max(0, Math.min(lodRangeMin ?? 0, maxLod));
const rangeMax = Math.max(rangeMin, Math.min(lodRangeMax ?? maxLod, maxLod));
// process all nodes
const nodes = this.octree.nodes;
for(let nodeIndex = 0; nodeIndex < nodes.length; nodeIndex++){
const node = nodes[nodeIndex];
// LOD for the node, clamped by configured range
// optimal target LOD based on distance and range
let optimalLodIndex = this.calculateNodeLod(localCameraPosition, localCameraForward, nodeIndex, maxLod, lodDistances, lodBehindPenalty);
if (optimalLodIndex < rangeMin) optimalLodIndex = rangeMin;
if (optimalLodIndex > rangeMax) optimalLodIndex = rangeMax;
const currentLodIndex = this.nodeLods[nodeIndex];
// Determine desired display LOD using underfill strategy within allowed range
const desiredLodIndex = this.selectDesiredLodIndex(node, optimalLodIndex, maxLod, lodUnderfillLimit);
// if desired LOD differs from currently displayed LOD
if (desiredLodIndex !== currentLodIndex) {
// Determine visibility based on the presence of a valid file index
const currentFileIndex = currentLodIndex >= 0 ? node.lods[currentLodIndex].fileIndex : -1;
const desiredFileIndex = desiredLodIndex >= 0 ? node.lods[desiredLodIndex].fileIndex : -1;
const wasVisible = currentFileIndex !== -1;
const willBeVisible = desiredFileIndex !== -1;
// if there's a pending transition, manage it without dropping the currently visible LOD
const pendingEntry = this.pendingDecrements.get(nodeIndex);
if (pendingEntry) {
// if desired target changed while previous target was still loading, cancel previous target for this node
if (pendingEntry.newFileIndex !== desiredFileIndex) {
// remove this node's interval from the previously pending target if it still exists
const prevPendingPlacement = this.filePlacements[pendingEntry.newFileIndex];
if (prevPendingPlacement) {
this.decrementFileRef(pendingEntry.newFileIndex, nodeIndex);
}
// update or clear pending transition
if (wasVisible && willBeVisible) {
this.pendingDecrements.set(nodeIndex, {
oldFileIndex: pendingEntry.oldFileIndex,
newFileIndex: desiredFileIndex
});
} else {
// no longer targeting a visible LOD; clear pending and let normal logic handle hide/show
this.pendingDecrements.delete(nodeIndex);
}
}
// if target stays the same, keep pending as-is until the resource loads
}
if (!wasVisible && willBeVisible) {
// becoming visible (invisible -> visible)
// if we had a previous pending visible-add for a different file, cancel it
const prevPendingFi = this.pendingVisibleAdds.get(nodeIndex);
if (prevPendingFi !== undefined && prevPendingFi !== desiredFileIndex) {
this.decrementFileRef(prevPendingFi, nodeIndex);
this.pendingVisibleAdds.delete(nodeIndex);
}
this.incrementFileRef(desiredFileIndex, nodeIndex, desiredLodIndex);
const newPlacement = this.filePlacements[desiredFileIndex];
if (newPlacement?.resource) {
// resource is ready now, display immediately
this.nodeLods[nodeIndex] = desiredLodIndex;
// clear any pending visible-add entry
this.pendingVisibleAdds.delete(nodeIndex);
} else {
// keep displayed as invisible until resource arrives; next update will promote
this.pendingVisibleAdds.set(nodeIndex, desiredFileIndex);
}
} else if (wasVisible && !willBeVisible) {
// becoming invisible (visible -> invisible)
// if there was a pending target for this node, cancel it first
const pendingEntry2 = this.pendingDecrements.get(nodeIndex);
if (pendingEntry2) {
this.decrementFileRef(pendingEntry2.newFileIndex, nodeIndex);
this.pendingDecrements.delete(nodeIndex);
}
this.decrementFileRef(currentFileIndex, nodeIndex);
this.nodeLods[nodeIndex] = -1;
// clear any pending visible-add entry
this.pendingVisibleAdds.delete(nodeIndex);
} else if (wasVisible && willBeVisible) {
// switching between visible LODs (visible -> visible)
this.incrementFileRef(desiredFileIndex, nodeIndex, desiredLodIndex);
const newPlacement = this.filePlacements[desiredFileIndex];
if (newPlacement?.resource) {
// new LOD ready - remove old LOD immediately
this.decrementFileRef(currentFileIndex, nodeIndex);
// clear any pending for this node if exists
this.pendingDecrements.delete(nodeIndex);
// update displayed lod now that switch is complete
this.nodeLods[nodeIndex] = desiredLodIndex;
// clear any pending visible-add entry
this.pendingVisibleAdds.delete(nodeIndex);
} else {
// new LOD not ready - track pending decrement for when it loads
this.pendingDecrements.set(nodeIndex, {
oldFileIndex: currentFileIndex,
newFileIndex: desiredFileIndex
});
// keep displayed lod as current until pending resolves
// ensure no pending visible-add entry remains
this.pendingVisibleAdds.delete(nodeIndex);
}
}
}
// Prefetch loading: request only the next-better LOD toward optimal
this.prefetchNextLod(node, desiredLodIndex, optimalLodIndex);
}
}
/**
* Increments reference count for a file and creates placement immediately.
*
* @param {number} fileIndex - The file index.
* @param {number} nodeIndex - The octree node index.
* @param {number} lodIndex - The LOD index for this node.
*/ incrementFileRef(fileIndex, nodeIndex, lodIndex) {
if (fileIndex === -1) return;
// check if this is the first reference
let placement = this.filePlacements[fileIndex];
if (!placement) {
// create placement (with null resource initially)
placement = new GSplatPlacement(null, this.placement.node, lodIndex);
this.filePlacements[fileIndex] = placement;
// If we scheduled a remove for this file in this update, cancel it
const removeScheduled = this.removedCandidates.delete(fileIndex);
if (!removeScheduled) {
this.octree.incRefCount(fileIndex);
}
// if resource is already loaded, allow it to be used
if (!this.addFilePlacement(fileIndex)) {
// resource not loaded yet, kick off load and add to pending
this.octree.ensureFileResource(fileIndex, this.assetLoader);
this.pending.add(fileIndex);
}
}
// Add interval for this node to the placement
const nodes = this.octree.nodes;
const node = nodes[nodeIndex];
const lod = node.lods[lodIndex];
// Create interval as Vec2(start, end)
const interval = new Vec2(lod.offset, lod.offset + lod.count - 1);
placement.intervals.set(nodeIndex, interval);
this.dirtyModifiedPlacements = true;
}
/**
* Decrements reference count for a file and removes placement if needed.
*
* @param {number} fileIndex - The file index.
* @param {number} nodeIndex - The octree node index.
*/ decrementFileRef(fileIndex, nodeIndex) {
if (fileIndex === -1) return;
const placement = this.filePlacements[fileIndex];
if (!placement) {
return;
}
if (placement) {
// remove interval for this node from the placement
placement.intervals.delete(nodeIndex);
this.dirtyModifiedPlacements = true;
// if this was the last reference, remove placement
if (placement.intervals.size === 0) {
// Only remove if it was added (has resource)
if (placement.resource) {
this.activePlacements.delete(placement);
}
// schedule a single decRef via world state
this.removedCandidates.add(fileIndex);
this.filePlacements[fileIndex] = null;
this.pending.delete(fileIndex);
}
}
}
/**
* Updates existing placement with loaded resource and adds to manager.
*
* @param {number} fileIndex - The file index.
* @returns {boolean} True if placement was updated and added to manager, false otherwise.
*/ addFilePlacement(fileIndex) {
const res = this.octree.getFileResource(fileIndex);
if (res) {
// get the existing placement and update its resource
const placement = this.filePlacements[fileIndex];
if (placement) {
placement.resource = res;
placement.aabb.copy(res.aabb);
this.activePlacements.add(placement);
this.dirtyModifiedPlacements = true;
// clear pending removal if we are reusing the file
this.removedCandidates.delete(fileIndex);
return true;
}
}
return false;
}
/**
* Tests if the octree instance has moved by more than the provided LOD update distance.
*
* @param {number} threshold - Distance threshold to trigger an update.
* @returns {boolean} True if the octree instance has moved by more than the threshold, false otherwise.
*/ testMoved(threshold) {
const position = this.placement.node.getPosition();
const length = position.distance(this.previousPosition);
if (length > threshold) {
return true;
}
return false;
}
/**
* Updates the previous position of the octree instance.
*/ updateMoved() {
this.previousPosition.copy(this.placement.node.getPosition());
}
/**
* Updates the octree instance each frame.
*
* @param {Scene} scene - Optional scene for debug rendering.
* @returns {boolean} True if octree instance is dirty, false otherwise.
*/ update(scene) {
// handle pending loads
if (this.pending.size) {
for (const fileIndex of this.pending){
// check if the asset has finished loading and store it if so
this.octree.ensureFileResource(fileIndex, this.assetLoader);
// if resource became available, update placement and execute any pending decrements
if (this.addFilePlacement(fileIndex)) {
_tempCompletedUrls.push(fileIndex);
// Execute any pending decrements for nodes whose tracked newFileIndex now matches
for (const [nodeIndex, { oldFileIndex, newFileIndex }] of this.pendingDecrements){
if (newFileIndex === fileIndex) {
this.decrementFileRef(oldFileIndex, nodeIndex);
this.pendingDecrements.delete(nodeIndex);
// set displayed LOD to the LOD that maps to the newly ready file
let newLodIndex = 0;
const nodeLods = this.octree.nodes[nodeIndex].lods;
for(let li = 0; li < nodeLods.length; li++){
if (nodeLods[li].fileIndex === newFileIndex) {
newLodIndex = li;
break;
}
}
this.nodeLods[nodeIndex] = newLodIndex;
}
}
}
}
// mark LOD update if any resource completed
if (_tempCompletedUrls.length > 0) {
this.needsLodUpdate = true;
}
// remove completed items from pending
for (const fileIndex of _tempCompletedUrls){
this.pending.delete(fileIndex);
}
// clear temp array
_tempCompletedUrls.length = 0;
}
// watch prefetched loads for completion to allow promotion
this.pollPrefetchCompletions();
// check if any placements need LOD update
const dirty = this.dirtyModifiedPlacements;
this.dirtyModifiedPlacements = false;
return dirty;
}
// debug render world space bounds for octree nodes based on current LOD selection
debugRender(scene) {
Debug.call(()=>{
if (scene.gsplat.debugNodeAabbs) {
const modelMat = this.placement.node.getWorldTransform();
const nodes = this.octree.nodes;
for(let nodeIndex = 0; nodeIndex < nodes.length; nodeIndex++){
const lodIndex = this.nodeLods[nodeIndex];
if (lodIndex >= 0) {
const color = _lodColors[Math.min(lodIndex, _lodColors.length - 1)];
_tempDebugAabb.setFromTransformedAabb(nodes[nodeIndex].bounds, modelMat);
scene.immediate.drawWireAlignedBox(_tempDebugAabb.getMin(), _tempDebugAabb.getMax(), color, true, scene.defaultDrawLayer);
}
}
}
});
}
/**
* Returns true if this instance requests LOD re-evaluation and resets the flag.
* @returns {boolean} True if LOD should be re-evaluated.
*/ consumeNeedsLodUpdate() {
const v = this.needsLodUpdate;
this.needsLodUpdate = false;
return v;
}
/**
* Polls prefetched file indices for completion and updates state.
*/ pollPrefetchCompletions() {
if (this.prefetchPending.size) {
// poll loader and store resource in octree if ready
for (const fileIndex of this.prefetchPending){
this.octree.ensureFileResource(fileIndex, this.assetLoader);
if (this.octree.getFileResource(fileIndex)) {
_tempCompletedUrls.push(fileIndex);
}
}
// remove completed from prefetchPending
if (_tempCompletedUrls.length > 0) {
this.needsLodUpdate = true;
}
for (const fileIndex of _tempCompletedUrls){
this.prefetchPending.delete(fileIndex);
}
_tempCompletedUrls.length = 0;
}
}
}
export { GSplatOctreeInstance };