Add threshold option to TileFlattening (#1084)

Author: gkjohnson

src/plugins/README.md

@@ -767,10 +767,10 @@ Returns whether the given object has been passed in as a shape.
 ### addShape
 
 ```js
-addShape( shape: Object3D, direction: Vector3 ): void
+addShape( shape: Object3D, direction: Vector3 = ( 0, - 1, 0 ), threshold: number = Infinity ): void
 ```
 
-Adds the given object as a shape to flatten to in addition to the direction to flatten.
+Adds the given object as a shape to flatten to in addition to the direction to flatten. The `threshold` field is the distance threshold under which vertices will be flattened. `Infinity` will always flatten while `0` will never flatten.
 
 ### updateShape
 

src/plugins/three/TileFlatteningPlugin.d.ts

@@ -3,7 +3,7 @@ import { Mesh } from 'three';
 export class TileFatteningPlugin {
 
 	hasShape( mesh: Mesh ): boolean;
-	addShape( mesh: Mesh, direction: Vector3 ): void;
+	addShape( mesh: Mesh, direction: Vector3, threshold: number ): void;
 	updateShape( mesh: Mesh ): void;
 	deleteShape( mesh ): boolean;
 	clearShapes(): void;

src/plugins/three/TileFlatteningPlugin.js

@@ -12,6 +12,7 @@ const _matrix = /* @__PURE__ */ new Matrix4();
 const _invMatrix = /* @__PURE__ */ new Matrix4();
 const _raycaster = /* @__PURE__ */ new Raycaster();
 const _doubleSidedMaterial = /* @__PURE__ */ new MeshBasicMaterial( { side: DoubleSide } );
+const RAYCAST_DISTANCE = 1e5;
 
 function calculateSphere( object, target ) {
 
@@ -143,6 +144,7 @@ export class TileFlatteningPlugin {
 			shape,
 			direction,
 			sphere,
+			threshold,
 		} ) => {
 
 			// TODO: if we save the sphere of the original mesh we can check the height to limit the tiles checked
@@ -189,11 +191,11 @@ export class TileFlatteningPlugin {
 						ray.origin
 							.fromBufferAttribute( position, i )
 							.applyMatrix4( _matrix )
-							.addScaledVector( direction, 1e5 );
-						_raycaster.far = 1e5;
+							.addScaledVector( direction, RAYCAST_DISTANCE );
+						_raycaster.far = RAYCAST_DISTANCE;
 
 						const hit = _raycaster.intersectObject( shape )[ 0 ];
-						if ( hit ) {
+						if ( hit && RAYCAST_DISTANCE - hit.distance < threshold ) {
 
 							hit.point.applyMatrix4( _invMatrix );
 							position.setXYZ( i, ...hit.point );
@@ -226,7 +228,7 @@ export class TileFlatteningPlugin {
 
 	}
 
-	addShape( mesh, direction = new Vector3( 0, - 1, 0 ) ) {
+	addShape( mesh, direction = new Vector3( 0, - 1, 0 ), threshold = Infinity ) {
 
 		if ( this.hasShape( mesh ) ) {
 
@@ -255,6 +257,7 @@ export class TileFlatteningPlugin {
 			shape: shape,
 			direction: direction.clone(),
 			sphere: sphere,
+			threshold: threshold,
 		} );
 
 	}