three-mesh-bvh/src/webgpu/common_functions.wgsl.js

A BVH implementation to speed up raycasting against three.js meshes.

/** @import { BVHComputeData } from './BVHComputeData.js' */
import { wgslFn, wgsl } from 'three/tsl';
import { rayStruct, bvhNodeBoundsStruct } from './tsl/structs.js';

/** @deprecated Use {@link BVHComputeData} instead. */
export const constants = wgsl( /* wgsl */`

	const BVH_STACK_DEPTH = 60u;
	const INFINITY = 1e20;
	const TRI_INTERSECT_EPSILON = 1e-5;

` );

/** @deprecated Use {@link BVHComputeData} instead. */
export const intersectionResultStruct = wgsl( /* wgsl */`
	struct IntersectionResult {
		indices: vec4u,
		normal: vec3f,
		didHit: bool,
		barycoord: vec3f,
		side: f32,
		dist: f32,
	};
` );

/** @deprecated Use {@link BVHComputeData} instead. */
export const getVertexAttribute = wgslFn( /* wgsl */`

	fn getVertexAttribute(
		barycoord: vec3f,
		indices: vec3u,
		attributeBuffer: ptr<storage, array<vec3f>, read>
	) -> vec3f {

		let n0 = attributeBuffer[ indices.x ];
		let n1 = attributeBuffer[ indices.y ];
		let n2 = attributeBuffer[ indices.z ];
		return barycoord.x * n0 + barycoord.y * n1 + barycoord.z * n2;

	}

` );

/** @deprecated Use {@link BVHComputeData} instead. */
export const intersectsBounds = wgslFn( /* wgsl */`

	fn intersectsBounds(
		ray: Ray,
		bounds: BVHBoundingBox,
		dist: ptr<function, f32>
	) -> bool {

		let boundsMin = vec3( bounds.min[0], bounds.min[1], bounds.min[2] );
		let boundsMax = vec3( bounds.max[0], bounds.max[1], bounds.max[2] );

		let invDir = 1.0 / ray.direction;
		let tMinPlane = ( boundsMin - ray.origin ) * invDir;
		let tMaxPlane = ( boundsMax - ray.origin ) * invDir;

		let tMinHit = vec3f(
			min( tMinPlane.x, tMaxPlane.x ),
			min( tMinPlane.y, tMaxPlane.y ),
			min( tMinPlane.z, tMaxPlane.z )
		);

		let tMaxHit = vec3f(
			max( tMinPlane.x, tMaxPlane.x ),
			max( tMinPlane.y, tMaxPlane.y ),
			max( tMinPlane.z, tMaxPlane.z )
		);

		let t0 = max( max( tMinHit.x, tMinHit.y ), tMinHit.z );
		let t1 = min( min( tMaxHit.x, tMaxHit.y ), tMaxHit.z );

		( *dist ) = max( t0, 0.0 );

		return t1 >= ( *dist );

	}

`, [ rayStruct, bvhNodeBoundsStruct ] );