playcanvas/build/playcanvas/src/scene/gsplat-unified/gsplat-frustum-culler.js

Open-source WebGL/WebGPU 3D engine for the web

import { Frustum } from "../../core/shape/frustum.js";
import { Mat4 } from "../../core/math/mat4.js";
import { BUFFERUSAGE_COPY_DST } from "../../platform/graphics/constants.js";
import { StorageBuffer } from "../../platform/graphics/storage-buffer.js";
const _viewProjMat = new Mat4();
const _frustum = new Frustum();
const BOUNDS_ENTRY_FLOATS = 8;
class GSplatFrustumCuller {
	device;
	boundsBuffer = null;
	totalBoundsEntries = 0;
	_allocatedBoundsEntries = 0;
	_boundsFloatView = null;
	_boundsUintView = null;
	_tmpSpheres = null;
	transformsBuffer = null;
	_allocatedTransformCount = 0;
	_transformsData = null;
	frustumPlanes = new Float32Array(24);
	fisheyeCameraPos = new Float32Array(3);
	fisheyeCameraForward = new Float32Array(3);
	fisheyeMaxTheta = Math.PI;
	constructor(device) {
		this.device = device;
	}
	destroy() {
		this.boundsBuffer?.destroy();
		this.transformsBuffer?.destroy();
	}
	updateBoundsData(boundsGroups) {
		let totalEntries = 0;
		for (let i = 0; i < boundsGroups.length; i++) {
			totalEntries += boundsGroups[i].numBoundsEntries;
		}
		this.totalBoundsEntries = totalEntries;
		if (totalEntries === 0) return;
		if (totalEntries > this._allocatedBoundsEntries) {
			this.boundsBuffer?.destroy();
			this._allocatedBoundsEntries = totalEntries;
			this.boundsBuffer = new StorageBuffer(this.device, totalEntries * BOUNDS_ENTRY_FLOATS * 4, BUFFERUSAGE_COPY_DST);
			const ab = new ArrayBuffer(totalEntries * BOUNDS_ENTRY_FLOATS * 4);
			this._boundsFloatView = new Float32Array(ab);
			this._boundsUintView = new Uint32Array(ab);
			this._tmpSpheres = new Float32Array(totalEntries * 4);
		}
		const floatView = this._boundsFloatView;
		const uintView = this._boundsUintView;
		const tmpSpheres = this._tmpSpheres;
		for (let i = 0; i < boundsGroups.length; i++) {
			const group = boundsGroups[i];
			const base = group.boundsBaseIndex;
			const count = group.numBoundsEntries;
			group.splat.writeBoundsSpheres(tmpSpheres, base * 4);
			for (let j = 0; j < count; j++) {
				const src = (base + j) * 4;
				const dst = (base + j) * BOUNDS_ENTRY_FLOATS;
				floatView[dst + 0] = tmpSpheres[src + 0];
				floatView[dst + 1] = tmpSpheres[src + 1];
				floatView[dst + 2] = tmpSpheres[src + 2];
				floatView[dst + 3] = tmpSpheres[src + 3];
				uintView[dst + 4] = i;
			}
		}
		this.boundsBuffer.write(0, floatView);
	}
	updateTransformsData(boundsGroups) {
		const numMatrices = boundsGroups.length;
		if (numMatrices === 0) return;
		if (numMatrices > this._allocatedTransformCount) {
			this.transformsBuffer?.destroy();
			this._allocatedTransformCount = numMatrices;
			this.transformsBuffer = new StorageBuffer(this.device, numMatrices * 12 * 4, BUFFERUSAGE_COPY_DST);
			this._transformsData = new Float32Array(numMatrices * 12);
		}
		const data = this._transformsData;
		let offset = 0;
		for (let i = 0; i < boundsGroups.length; i++) {
			const m = boundsGroups[i].splat.node.getWorldTransform().data;
			data[offset++] = m[0];
			data[offset++] = m[4];
			data[offset++] = m[8];
			data[offset++] = m[12];
			data[offset++] = m[1];
			data[offset++] = m[5];
			data[offset++] = m[9];
			data[offset++] = m[13];
			data[offset++] = m[2];
			data[offset++] = m[6];
			data[offset++] = m[10];
			data[offset++] = m[14];
		}
		this.transformsBuffer.write(0, data);
	}
	setFrustumPlanes(frustum) {
		const planes = this.frustumPlanes;
		for (let p = 0; p < 6; p++) {
			const plane = frustum.planes[p];
			planes[p * 4 + 0] = plane.normal.x;
			planes[p * 4 + 1] = plane.normal.y;
			planes[p * 4 + 2] = plane.normal.z;
			planes[p * 4 + 3] = plane.distance;
		}
	}
	computeFrustumPlanes(projectionMatrix, viewMatrix) {
		_viewProjMat.mul2(projectionMatrix, viewMatrix);
		_frustum.setFromMat4(_viewProjMat);
		this.setFrustumPlanes(_frustum);
	}
	setFisheyeData(cameraPos, cameraForward, maxTheta) {
		this.fisheyeCameraPos[0] = cameraPos.x;
		this.fisheyeCameraPos[1] = cameraPos.y;
		this.fisheyeCameraPos[2] = cameraPos.z;
		this.fisheyeCameraForward[0] = cameraForward.x;
		this.fisheyeCameraForward[1] = cameraForward.y;
		this.fisheyeCameraForward[2] = cameraForward.z;
		this.fisheyeMaxTheta = maxTheta;
	}
}
export {
	GSplatFrustumCuller
};