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BVHCast, InterectsGeometry: Remove some Box3 conversions #800

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gkjohnson wants to merge 2 commits into from
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BVHCast, InterectsGeometry: Remove some Box3 conversions #800

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91b927e
optimize intersects geometry, bvhcast
gkjohnson Nov 27, 2025
ad0a504
Merge remote-tracking branch 'origin/master' into bvh-geometry-inters…
gkjohnson Dec 3, 2025
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38 changes: 14 additions & 24 deletions src/core/cast/bvhcast.js
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Original file line number Diff line number Diff line change
@@ -1,17 +1,12 @@
import { Box3, Matrix4 } from 'three';
import { BufferStack } from '../utils/BufferStack.js';
import { BOUNDING_DATA_INDEX, COUNT, IS_LEAF, LEFT_NODE, OFFSET, RIGHT_NODE } from '../utils/nodeBufferUtils.js';
import { arrayToBox } from '../../utils/ArrayBoxUtilities.js';
import { arrayToBox, arrayIntersectsBox } from '../../utils/ArrayBoxUtilities.js';
import { PrimitivePool } from '../../utils/PrimitivePool.js';

const _bufferStack1 = new BufferStack.constructor();
const _bufferStack2 = new BufferStack.constructor();
const _boxPool = new PrimitivePool( () => new Box3() );
const _leftBox1 = new Box3();
const _rightBox1 = new Box3();

const _leftBox2 = new Box3();
const _rightBox2 = new Box3();

let _active = false;

Expand Down Expand Up @@ -170,12 +165,10 @@ function _traverse(
// get the child bounds to check before traversal
const cl1 = LEFT_NODE( node1Index32 );
const cr1 = RIGHT_NODE( node1Index32, uint32Array1 );
arrayToBox( BOUNDING_DATA_INDEX( cl1 ), float32Array1, _leftBox1 );
arrayToBox( BOUNDING_DATA_INDEX( cr1 ), float32Array1, _rightBox1 );

// precompute the intersections otherwise the global boxes will be modified during traversal
const intersectCl1 = newBox.intersectsBox( _leftBox1 );
const intersectCr1 = newBox.intersectsBox( _rightBox1 );
const intersectCl1 = arrayIntersectsBox( BOUNDING_DATA_INDEX( cl1 ), float32Array1, newBox );
const intersectCr1 = arrayIntersectsBox( BOUNDING_DATA_INDEX( cr1 ), float32Array1, newBox );
result = (
intersectCl1 && _traverse(
node2Index32, cl1, matrix1to2, matrix2to1, intersectsRangesFunc,
Expand All @@ -200,11 +193,10 @@ function _traverse(
// get the child bounds to check
const cl2 = LEFT_NODE( node2Index32 );
const cr2 = RIGHT_NODE( node2Index32, uint32Array2 );
arrayToBox( BOUNDING_DATA_INDEX( cl2 ), float32Array2, _leftBox2 );
arrayToBox( BOUNDING_DATA_INDEX( cr2 ), float32Array2, _rightBox2 );

const leftIntersects = currBox.intersectsBox( _leftBox2 );
const rightIntersects = currBox.intersectsBox( _rightBox2 );
const leftIntersects = arrayIntersectsBox( BOUNDING_DATA_INDEX( cl2 ), float32Array2, currBox );
const rightIntersects = arrayIntersectsBox( BOUNDING_DATA_INDEX( cr2 ), float32Array2, currBox );

if ( leftIntersects && rightIntersects ) {

// continue to traverse both children if they both intersect
Expand Down Expand Up @@ -234,16 +226,15 @@ function _traverse(
// SWAP
// if only one box intersects then we have to swap to the other bvh to continue
const newBox = _boxPool.getPrimitive();
newBox.copy( _leftBox2 ).applyMatrix4( matrix2to1 );
arrayToBox( BOUNDING_DATA_INDEX( cl2 ), float32Array2, newBox );
newBox.applyMatrix4( matrix2to1 );

const cl1 = LEFT_NODE( node1Index32 );
const cr1 = RIGHT_NODE( node1Index32, uint32Array1 );
arrayToBox( BOUNDING_DATA_INDEX( cl1 ), float32Array1, _leftBox1 );
arrayToBox( BOUNDING_DATA_INDEX( cr1 ), float32Array1, _rightBox1 );

// precompute the intersections otherwise the global boxes will be modified during traversal
const intersectCl1 = newBox.intersectsBox( _leftBox1 );
const intersectCr1 = newBox.intersectsBox( _rightBox1 );
const intersectCl1 = arrayIntersectsBox( BOUNDING_DATA_INDEX( cl1 ), float32Array1, newBox );
const intersectCr1 = arrayIntersectsBox( BOUNDING_DATA_INDEX( cr1 ), float32Array1, newBox );
result = (
intersectCl1 && _traverse(
cl2, cl1, matrix1to2, matrix2to1, intersectsRangesFunc,
Expand Down Expand Up @@ -278,16 +269,15 @@ function _traverse(
// SWAP
// if only one box intersects then we have to swap to the other bvh to continue
const newBox = _boxPool.getPrimitive();
newBox.copy( _rightBox2 ).applyMatrix4( matrix2to1 );
arrayToBox( BOUNDING_DATA_INDEX( cr2 ), float32Array2, newBox );
newBox.applyMatrix4( matrix2to1 );

const cl1 = LEFT_NODE( node1Index32 );
const cr1 = RIGHT_NODE( node1Index32, uint32Array1 );
arrayToBox( BOUNDING_DATA_INDEX( cl1 ), float32Array1, _leftBox1 );
arrayToBox( BOUNDING_DATA_INDEX( cr1 ), float32Array1, _rightBox1 );

// precompute the intersections otherwise the global boxes will be modified during traversal
const intersectCl1 = newBox.intersectsBox( _leftBox1 );
const intersectCr1 = newBox.intersectsBox( _rightBox1 );
const intersectCl1 = arrayIntersectsBox( BOUNDING_DATA_INDEX( cl1 ), float32Array1, newBox );
const intersectCr1 = arrayIntersectsBox( BOUNDING_DATA_INDEX( cr1 ), float32Array1, newBox );
result = (
intersectCl1 && _traverse(
cr2, cl1, matrix1to2, matrix2to1, intersectsRangesFunc,
Expand Down
25 changes: 20 additions & 5 deletions src/core/cast/intersectsGeometry.template.js
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ import { Box3, Matrix4 } from 'three';
import { OrientedBox } from '../../math/OrientedBox.js';
import { ExtendedTriangle } from '../../math/ExtendedTriangle.js';
import { setTriangle } from '../../utils/TriangleUtilities.js';
import { arrayToBox } from '../../utils/ArrayBoxUtilities.js';
import { setOBBFromArray } from '../../utils/ArrayBoxUtilities.js';
import { COUNT, OFFSET, IS_LEAF, BOUNDING_DATA_INDEX } from '../utils/nodeBufferUtils.js';
import { BufferStack } from '../utils/BufferStack.js';
import { getTriCount } from '../build/geometryUtils.js';
Expand Down Expand Up @@ -65,9 +65,8 @@ function _intersectsGeometry( nodeIndex32, bvh, otherGeometry, geometryToBvh, ca
if ( otherGeometry.boundsTree ) {

// if there's a bounds tree
arrayToBox( BOUNDING_DATA_INDEX( nodeIndex32 ), float32Array, obb2 );
setOBBFromArray( obb2, BOUNDING_DATA_INDEX( nodeIndex32 ), float32Array );
obb2.matrix.copy( invertedMat );
obb2.needsUpdate = true;

// TODO: use a triangle iteration function here
const res = otherGeometry.boundsTree.shapecast( {
Expand Down Expand Up @@ -178,14 +177,30 @@ function _intersectsGeometry( nodeIndex32, bvh, otherGeometry, geometryToBvh, ca
const left = nodeIndex32 + 8;
const right = uint32Array[ nodeIndex32 + 6 ];

arrayToBox( BOUNDING_DATA_INDEX( left ), float32Array, boundingBox );
// Check left child - inline bounds setting to avoid function call
const leftBoundsIndex = BOUNDING_DATA_INDEX( left );
boundingBox.min.x = float32Array[ leftBoundsIndex ];
boundingBox.min.y = float32Array[ leftBoundsIndex + 1 ];
boundingBox.min.z = float32Array[ leftBoundsIndex + 2 ];
boundingBox.max.x = float32Array[ leftBoundsIndex + 3 ];
boundingBox.max.y = float32Array[ leftBoundsIndex + 4 ];
boundingBox.max.z = float32Array[ leftBoundsIndex + 5 ];

const leftIntersection =
cachedObb.intersectsBox( boundingBox ) &&
_intersectsGeometry( left, bvh, otherGeometry, geometryToBvh, cachedObb );

if ( leftIntersection ) return true;

arrayToBox( BOUNDING_DATA_INDEX( right ), float32Array, boundingBox );
// Check right child - inline bounds setting to avoid function call
const rightBoundsIndex = BOUNDING_DATA_INDEX( right );
boundingBox.min.x = float32Array[ rightBoundsIndex ];
boundingBox.min.y = float32Array[ rightBoundsIndex + 1 ];
boundingBox.min.z = float32Array[ rightBoundsIndex + 2 ];
boundingBox.max.x = float32Array[ rightBoundsIndex + 3 ];
boundingBox.max.y = float32Array[ rightBoundsIndex + 4 ];
boundingBox.max.z = float32Array[ rightBoundsIndex + 5 ];

const rightIntersection =
cachedObb.intersectsBox( boundingBox ) &&
_intersectsGeometry( right, bvh, otherGeometry, geometryToBvh, cachedObb );
Expand Down
28 changes: 28 additions & 0 deletions src/utils/ArrayBoxUtilities.js
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,34 @@ export function arrayToBox( nodeIndex32, array, target ) {

}

// Optimized box intersection test that reads directly from array without creating a Box3
export function arrayIntersectsBox( nodeIndex32, array, box ) {

return array[ nodeIndex32 + 3 ] >= box.min.x &&
array[ nodeIndex32 ] <= box.max.x &&
array[ nodeIndex32 + 4 ] >= box.min.y &&
array[ nodeIndex32 + 1 ] <= box.max.y &&
array[ nodeIndex32 + 5 ] >= box.min.z &&
array[ nodeIndex32 + 2 ] <= box.max.z;

}

// Helper for OBB intersection test - reads bounds from array and sets OBB min/max directly
// This avoids creating an intermediate Box3 object for the common case
export function setOBBFromArray( obb, nodeIndex32, array ) {

obb.min.x = array[ nodeIndex32 ];
obb.min.y = array[ nodeIndex32 + 1 ];
obb.min.z = array[ nodeIndex32 + 2 ];

obb.max.x = array[ nodeIndex32 + 3 ];
obb.max.y = array[ nodeIndex32 + 4 ];
obb.max.z = array[ nodeIndex32 + 5 ];

obb.needsUpdate = true;

}

export function makeEmptyBounds( target ) {

target[ 0 ] = target[ 1 ] = target[ 2 ] = Infinity;
Expand Down
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