Line: Honor last segment of LineLoop in raycast(). (#28114)

* Line: implement raycast() method for LineLoop

* Line(#28114): changes for better consistency with Mesh.js

---------

Co-authored-by: 唐壤 <tangrang@minieye.cc>

src/objects/Line.js

@@ -7,12 +7,16 @@ import { LineBasicMaterial } from '../materials/LineBasicMaterial.js';
 import { BufferGeometry } from '../core/BufferGeometry.js';
 import { Float32BufferAttribute } from '../core/BufferAttribute.js';
 
-const _start = /*@__PURE__*/ new Vector3();
-const _end = /*@__PURE__*/ new Vector3();
+const _vStart = /*@__PURE__*/ new Vector3();
+const _vEnd = /*@__PURE__*/ new Vector3();
+
 const _inverseMatrix = /*@__PURE__*/ new Matrix4();
 const _ray = /*@__PURE__*/ new Ray();
 const _sphere = /*@__PURE__*/ new Sphere();
 
+const _intersectPointOnRay = /*@__PURE__*/ new Vector3();
+const _intersectPointOnSegment = /*@__PURE__*/ new Vector3();
+
 class Line extends Object3D {
 
 	constructor( geometry = new BufferGeometry(), material = new LineBasicMaterial() ) {
@@ -54,11 +58,11 @@ class Line extends Object3D {
 
 			for ( let i = 1, l = positionAttribute.count; i < l; i ++ ) {
 
-				_start.fromBufferAttribute( positionAttribute, i - 1 );
-				_end.fromBufferAttribute( positionAttribute, i );
+				_vStart.fromBufferAttribute( positionAttribute, i - 1 );
+				_vEnd.fromBufferAttribute( positionAttribute, i );
 
 				lineDistances[ i ] = lineDistances[ i - 1 ];
-				lineDistances[ i ] += _start.distanceTo( _end );
+				lineDistances[ i ] += _vStart.distanceTo( _vEnd );
 
 			}
 
@@ -99,10 +103,6 @@ class Line extends Object3D {
 		const localThreshold = threshold / ( ( this.scale.x + this.scale.y + this.scale.z ) / 3 );
 		const localThresholdSq = localThreshold * localThreshold;
 
-		const vStart = new Vector3();
-		const vEnd = new Vector3();
-		const interSegment = new Vector3();
-		const interRay = new Vector3();
 		const step = this.isLineSegments ? 2 : 1;
 
 		const index = geometry.index;
@@ -119,31 +119,28 @@ class Line extends Object3D {
 				const a = index.getX( i );
 				const b = index.getX( i + 1 );
 
-				vStart.fromBufferAttribute( positionAttribute, a );
-				vEnd.fromBufferAttribute( positionAttribute, b );
+				const intersect = checkIntersection( this, raycaster, _ray, localThresholdSq, a, b );
+
+				if ( intersect ) {
 
-				const distSq = _ray.distanceSqToSegment( vStart, vEnd, interRay, interSegment );
+					intersects.push( intersect );
 
-				if ( distSq > localThresholdSq ) continue;
+				}
+
+			}
 
-				interRay.applyMatrix4( this.matrixWorld ); //Move back to world space for distance calculation
+			if ( this.isLineLoop ) {
 
-				const distance = raycaster.ray.origin.distanceTo( interRay );
+				const a = index.getX( end - 1 );
+				const b = index.getX( start );
 
-				if ( distance < raycaster.near || distance > raycaster.far ) continue;
+				const intersect = checkIntersection( this, raycaster, _ray, localThresholdSq, a, b );
 
-				intersects.push( {
+				if ( intersect ) {
 
-					distance: distance,
-					// What do we want? intersection point on the ray or on the segment??
-					// point: raycaster.ray.at( distance ),
-					point: interSegment.clone().applyMatrix4( this.matrixWorld ),
-					index: i,
-					face: null,
-					faceIndex: null,
-					object: this
+					intersects.push( intersect );
 
-				} );
+				}
 
 			}
 
@@ -154,31 +151,25 @@ class Line extends Object3D {
 
 			for ( let i = start, l = end - 1; i < l; i += step ) {
 
-				vStart.fromBufferAttribute( positionAttribute, i );
-				vEnd.fromBufferAttribute( positionAttribute, i + 1 );
+				const intersect = checkIntersection( this, raycaster, _ray, localThresholdSq, i, i + 1 );
+
+				if ( intersect ) {
 
-				const distSq = _ray.distanceSqToSegment( vStart, vEnd, interRay, interSegment );
+					intersects.push( intersect );
 
-				if ( distSq > localThresholdSq ) continue;
+				}
 
-				interRay.applyMatrix4( this.matrixWorld ); //Move back to world space for distance calculation
+			}
 
-				const distance = raycaster.ray.origin.distanceTo( interRay );
+			if ( this.isLineLoop ) {
 
-				if ( distance < raycaster.near || distance > raycaster.far ) continue;
+				const intersect = checkIntersection( this, raycaster, _ray, localThresholdSq, end - 1, start );
 
-				intersects.push( {
+				if ( intersect ) {
 
-					distance: distance,
-					// What do we want? intersection point on the ray or on the segment??
-					// point: raycaster.ray.at( distance ),
-					point: interSegment.clone().applyMatrix4( this.matrixWorld ),
-					index: i,
-					face: null,
-					faceIndex: null,
-					object: this
+					intersects.push( intersect );
 
-				} );
+				}
 
 			}
 
@@ -219,4 +210,36 @@ class Line extends Object3D {
 
 }
 
+function checkIntersection( object, raycaster, ray, thresholdSq, a, b ) {
+
+	const positionAttribute = object.geometry.attributes.position;
+
+	_vStart.fromBufferAttribute( positionAttribute, a );
+	_vEnd.fromBufferAttribute( positionAttribute, b );
+
+	const distSq = ray.distanceSqToSegment( _vStart, _vEnd, _intersectPointOnRay, _intersectPointOnSegment );
+
+	if ( distSq > thresholdSq ) return;
+
+	_intersectPointOnRay.applyMatrix4( object.matrixWorld ); // Move back to world space for distance calculation
+
+	const distance = raycaster.ray.origin.distanceTo( _intersectPointOnRay );
+
+	if ( distance < raycaster.near || distance > raycaster.far ) return;
+
+	return {
+
+		distance: distance,
+		// What do we want? intersection point on the ray or on the segment??
+		// point: raycaster.ray.at( distance ),
+		point: _intersectPointOnSegment.clone().applyMatrix4( object.matrixWorld ),
+		index: a,
+		face: null,
+		faceIndex: null,
+		object: object
+
+	};
+
+}
+
 export { Line };