BufferAttribute type / precision conversion API

examples/jsm/objects/GroundedSkybox.js

@@ -1,4 +1,4 @@
-import { Mesh, MeshBasicMaterial, SphereGeometry, Vector3 } from 'three';
+import { Mesh, MeshBasicMaterial, SphereGeometry, Vector3, Float16BufferAttribute } from 'three';
 
 /**
  * A ground-projected skybox.
@@ -36,7 +36,13 @@ class GroundedSkybox extends Mesh {
 
 		}
 
-		const geometry = new SphereGeometry( radius, 2 * resolution, resolution );
+		const geometry = new SphereGeometry(radius, 2 * resolution, resolution, 0, Math.PI * 2, 0, Math.PI,
+			{
+				position: Float16BufferAttribute,
+				uv: Float16BufferAttribute,
+				normal: null
+			}
+		);
 		geometry.scale( 1, 1, - 1 );
 
 		const pos = geometry.getAttribute( 'position' );
@@ -52,15 +58,15 @@ class GroundedSkybox extends Mesh {
 				const f =
 						tmp.y < y1 ? - height / tmp.y : ( 1 - tmp.y * tmp.y / ( 3 * y1 * y1 ) );
 				tmp.multiplyScalar( f );
-				tmp.toArray( pos.array, 3 * i );
+				pos.setXYZ(i, tmp.x, tmp.y, tmp.z);
 
 			}
 
 		}
 
 		pos.needsUpdate = true;
 
-		super( geometry, new MeshBasicMaterial( { map, depthWrite: false } ) );
+		super(geometry, new MeshBasicMaterial({ map, depthWrite: false, name: "GroundedSkybox" }));
 
 	}
 

src/core/BufferAttribute.js

@@ -653,6 +653,40 @@ class BufferAttribute {
 
 	}
 
+	/**
+	 * Return this BufferAttribute with a different type.
+	 *
+	 * @param {Function} TargetType - BufferAttribute type to return.
+	 * @return {BufferAttribute} Converted BufferAttribute.
+	 */
+	convert( TargetType ) {
+
+		if ( this.constructor === TargetType ) return this;
+
+		const target = new TargetType( this.count * this.itemSize, this.itemSize, this.normalized );
+
+		if ( target.isFloat16BufferAttribute )
+			target.normalized = false;
+
+		for ( let i = 0; i < this.count; ++ i ) {
+
+			switch ( this.itemSize ) {
+
+				case 1: target.setX( i, this.getX( i ) ); break;
+				case 2: target.setXY( i, this.getX( i ), this.getY( i ) ); break;
+				case 3: target.setXYZ( i, this.getX( i ), this.getY( i ), this.getZ( i ) ); break;
+				case 4: target.setXYZW( i, this.getX( i ), this.getY( i ), this.getZ( i ), this.getW( i ) ); break;
+
+			}
+
+		}
+
+		target.name = this.name;
+
+		return target;
+
+	}
+
 	/**
 	 * Serializes the buffer attribute into JSON.
 	 *

src/geometries/SphereGeometry.js

@@ -27,8 +27,9 @@ class SphereGeometry extends BufferGeometry {
 	 * @param {number} [phiLength=Math.PI*2] - The horizontal sweep angle size.
 	 * @param {number} [thetaStart=0] - The vertical starting angle in radians.
 	 * @param {number} [thetaLength=Math.PI] - The vertical sweep angle size.
+	 * @param {Object} [attributes={}] - Attribute precision specifiers.
 	 */
-	constructor( radius = 1, widthSegments = 32, heightSegments = 16, phiStart = 0, phiLength = Math.PI * 2, thetaStart = 0, thetaLength = Math.PI ) {
+	constructor( radius = 1, widthSegments = 32, heightSegments = 16, phiStart = 0, phiLength = Math.PI * 2, thetaStart = 0, thetaLength = Math.PI, precision = { position: Float32BufferAttribute, uv: Float32BufferAttribute, normal: Float32BufferAttribute } ) {
 
 		super();
 
@@ -48,7 +49,8 @@ class SphereGeometry extends BufferGeometry {
 			phiStart: phiStart,
 			phiLength: phiLength,
 			thetaStart: thetaStart,
-			thetaLength: thetaLength
+			thetaLength: thetaLength,
+			precision: precision
 		};
 
 		widthSegments = Math.max( 3, Math.floor( widthSegments ) );
@@ -141,9 +143,11 @@ class SphereGeometry extends BufferGeometry {
 		// build geometry
 
 		this.setIndex( indices );
-		this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
-		this.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );
-		this.setAttribute( 'uv', new Float32BufferAttribute( uvs, 2 ) );
+		this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ).convert( precision.position ) );
+		if ( precision.normal !== null )
+			this.setAttribute( 'normal', new Float32BufferAttribute( normals, 3, true ).convert( precision.normal ) );
+		if ( precision.uv !== null )
+			this.setAttribute( 'uv', new Float32BufferAttribute( uvs, 2, true ).convert( precision.uv ) );
 
 	}
 
@@ -166,7 +170,7 @@ class SphereGeometry extends BufferGeometry {
 	 */
 	static fromJSON( data ) {
 
-		return new SphereGeometry( data.radius, data.widthSegments, data.heightSegments, data.phiStart, data.phiLength, data.thetaStart, data.thetaLength );
+		return new SphereGeometry( data.radius, data.widthSegments, data.heightSegments, data.phiStart, data.phiLength, data.thetaStart, data.thetaLength, data.precision );
 
 	}