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import {
BufferGeometry,
Float32BufferAttribute,
LineSegments,
LineBasicMaterial,
Matrix3,
Vector3
} from 'three';
const _v1 = new Vector3();
const _v2 = new Vector3();
const _normalMatrix = new Matrix3();
class VertexNormalsHelper extends LineSegments {
constructor( object, size = 1, color = 0xff0000 ) {
const geometry = new BufferGeometry();
const nNormals = object.geometry.attributes.normal.count;
const positions = new Float32BufferAttribute( nNormals * 2 * 3, 3 );
geometry.setAttribute( 'position', positions );
super( geometry, new LineBasicMaterial( { color, toneMapped: false } ) );
this.object = object;
this.size = size;
this.type = 'VertexNormalsHelper';
//
this.matrixAutoUpdate = false;
this.update();
}
update() {
this.object.updateMatrixWorld( true );
_normalMatrix.getNormalMatrix( this.object.matrixWorld );
const matrixWorld = this.object.matrixWorld;
const position = this.geometry.attributes.position;
//
const objGeometry = this.object.geometry;
if ( objGeometry ) {
const objPos = objGeometry.attributes.position;
const objNorm = objGeometry.attributes.normal;
let idx = 0;
// for simplicity, ignore index and drawcalls, and render every normal
for ( let j = 0, jl = objPos.count; j < jl; j ++ ) {
_v1.fromBufferAttribute( objPos, j ).applyMatrix4( matrixWorld );
_v2.fromBufferAttribute( objNorm, j );
_v2.applyMatrix3( _normalMatrix ).normalize().multiplyScalar( this.size ).add( _v1 );
position.setXYZ( idx, _v1.x, _v1.y, _v1.z );
idx = idx + 1;
position.setXYZ( idx, _v2.x, _v2.y, _v2.z );
idx = idx + 1;
}
}
position.needsUpdate = true;
}
dispose() {
this.geometry.dispose();
this.material.dispose();
}
}
export { VertexNormalsHelper };