Implement basic support for morphTargetsRelative

This adds the attribute and the necessary plumbing for various JS
functions; there's no support for specifying this for the shader to
consume yet.

src/core/BufferGeometry.d.ts

@@ -40,6 +40,7 @@ export class BufferGeometry extends EventDispatcher {
 	morphAttributes: {
 		[name: string]: ( BufferAttribute | InterleavedBufferAttribute )[];
 	};
+	morphTargetsRelative: boolean;
 	groups: { start: number; count: number; materialIndex?: number }[];
 	boundingBox: Box3;
 	boundingSphere: Sphere;

src/core/BufferGeometry.js

@@ -37,6 +37,7 @@ function BufferGeometry() {
 	this.attributes = {};
 
 	this.morphAttributes = {};
+	this.morphTargetsRelative = false;
 
 	this.groups = [];
 
@@ -596,8 +597,17 @@ BufferGeometry.prototype = Object.assign( Object.create( EventDispatcher.prototy
 					var morphAttribute = morphAttributesPosition[ i ];
 					_box.setFromBufferAttribute( morphAttribute );
 
-					this.boundingBox.expandByPoint( _box.min );
-					this.boundingBox.expandByPoint( _box.max );
+					if ( this.morphTargetsRelative ) {
+
+						this.boundingBox.expandByVector( _box.min );
+						this.boundingBox.expandByVector( _box.max );
+
+					} else {
+
+						this.boundingBox.expandByPoint( _box.min );
+						this.boundingBox.expandByPoint( _box.max );
+
+					}
 
 				}
 
@@ -645,8 +655,17 @@ BufferGeometry.prototype = Object.assign( Object.create( EventDispatcher.prototy
 					var morphAttribute = morphAttributesPosition[ i ];
 					_boxMorphTargets.setFromBufferAttribute( morphAttribute );
 
-					_box.expandByPoint( _boxMorphTargets.min );
-					_box.expandByPoint( _boxMorphTargets.max );
+					if ( this.morphTargetsRelative ) {
+
+						_box.boundingBox.expandByVector( _boxMorphTargets.min );
+						_box.boundingBox.expandByVector( _boxMorphTargets.max );
+
+					} else {
+
+						_box.expandByPoint( _boxMorphTargets.min );
+						_box.expandByPoint( _boxMorphTargets.max );
+
+					}
 
 				}
 
@@ -674,11 +693,19 @@ BufferGeometry.prototype = Object.assign( Object.create( EventDispatcher.prototy
 				for ( var i = 0, il = morphAttributesPosition.length; i < il; i ++ ) {
 
 					var morphAttribute = morphAttributesPosition[ i ];
+					var morphTargetsRelative = this.morphTargetsRelative;
 
 					for ( var j = 0, jl = morphAttribute.count; j < jl; j ++ ) {
 
 						_vector.fromBufferAttribute( morphAttribute, j );
 
+						if ( morphTargetsRelative ) {
+
+							_offset.fromBufferAttribute( position, j );
+							_vector.add( _offset );
+
+						}
+
 						maxRadiusSq = Math.max( maxRadiusSq, center.distanceToSquared( _vector ) );
 
 					}
@@ -1055,7 +1082,12 @@ BufferGeometry.prototype = Object.assign( Object.create( EventDispatcher.prototy
 
 		}
 
-		if ( hasMorphAttributes ) data.data.morphAttributes = morphAttributes;
+		if ( hasMorphAttributes ) {
+
+			data.data.morphAttributes = morphAttributes;
+			data.data.morphTargetsRelative = this.morphTargetsRelative;
+
+		}
 
 		var groups = this.groups;
 
@@ -1167,6 +1199,8 @@ BufferGeometry.prototype = Object.assign( Object.create( EventDispatcher.prototy
 
 		}
 
+		this.morphTargetsRelative = source.morphTargetsRelative;
+
 		// groups
 
 		var groups = source.groups;

src/objects/Mesh.js

@@ -173,6 +173,7 @@ Mesh.prototype = Object.assign( Object.create( Object3D.prototype ), {
 			var index = geometry.index;
 			var position = geometry.attributes.position;
 			var morphPosition = geometry.morphAttributes.position;
+			var morphTargetsRelative = geometry.morphTargetsRelative;
 			var uv = geometry.attributes.uv;
 			var uv2 = geometry.attributes.uv2;
 			var groups = geometry.groups;
@@ -201,7 +202,7 @@ Mesh.prototype = Object.assign( Object.create( Object3D.prototype ), {
 							b = index.getX( j + 1 );
 							c = index.getX( j + 2 );
 
-							intersection = checkBufferGeometryIntersection( this, groupMaterial, raycaster, _ray, position, morphPosition, uv, uv2, a, b, c );
+							intersection = checkBufferGeometryIntersection( this, groupMaterial, raycaster, _ray, position, morphPosition, morphTargetsRelative, uv, uv2, a, b, c );
 
 							if ( intersection ) {
 
@@ -226,7 +227,7 @@ Mesh.prototype = Object.assign( Object.create( Object3D.prototype ), {
 						b = index.getX( i + 1 );
 						c = index.getX( i + 2 );
 
-						intersection = checkBufferGeometryIntersection( this, material, raycaster, _ray, position, morphPosition, uv, uv2, a, b, c );
+						intersection = checkBufferGeometryIntersection( this, material, raycaster, _ray, position, morphPosition, morphTargetsRelative, uv, uv2, a, b, c );
 
 						if ( intersection ) {
 
@@ -259,7 +260,7 @@ Mesh.prototype = Object.assign( Object.create( Object3D.prototype ), {
 							b = j + 1;
 							c = j + 2;
 
-							intersection = checkBufferGeometryIntersection( this, groupMaterial, raycaster, _ray, position, morphPosition, uv, uv2, a, b, c );
+							intersection = checkBufferGeometryIntersection( this, groupMaterial, raycaster, _ray, position, morphPosition, morphTargetsRelative, uv, uv2, a, b, c );
 
 							if ( intersection ) {
 
@@ -284,7 +285,7 @@ Mesh.prototype = Object.assign( Object.create( Object3D.prototype ), {
 						b = i + 1;
 						c = i + 2;
 
-						intersection = checkBufferGeometryIntersection( this, material, raycaster, _ray, position, morphPosition, uv, uv2, a, b, c );
+						intersection = checkBufferGeometryIntersection( this, material, raycaster, _ray, position, morphPosition, morphTargetsRelative, uv, uv2, a, b, c );
 
 						if ( intersection ) {
 
@@ -388,7 +389,7 @@ function checkIntersection( object, material, raycaster, ray, pA, pB, pC, point
 
 }
 
-function checkBufferGeometryIntersection( object, material, raycaster, ray, position, morphPosition, uv, uv2, a, b, c ) {
+function checkBufferGeometryIntersection( object, material, raycaster, ray, position, morphPosition, morphTargetsRelative, uv, uv2, a, b, c ) {
 
 	_vA.fromBufferAttribute( position, a );
 	_vB.fromBufferAttribute( position, b );
@@ -413,9 +414,19 @@ function checkBufferGeometryIntersection( object, material, raycaster, ray, posi
 			_tempB.fromBufferAttribute( morphAttribute, b );
 			_tempC.fromBufferAttribute( morphAttribute, c );
 
-			_morphA.addScaledVector( _tempA.sub( _vA ), influence );
-			_morphB.addScaledVector( _tempB.sub( _vB ), influence );
-			_morphC.addScaledVector( _tempC.sub( _vC ), influence );
+			if ( morphTargetsRelative ) {
+
+				_morphA.addScaledVector( _tempA, influence );
+				_morphB.addScaledVector( _tempB, influence );
+				_morphC.addScaledVector( _tempC, influence );
+
+			} else {
+
+				_morphA.addScaledVector( _tempA.sub( _vA ), influence );
+				_morphB.addScaledVector( _tempB.sub( _vB ), influence );
+				_morphC.addScaledVector( _tempC.sub( _vC ), influence );
+
+			}
 
 		}