89 lines
1.6 KiB
JavaScript
89 lines
1.6 KiB
JavaScript
import {
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BufferGeometry,
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Float32BufferAttribute,
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LineSegments,
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LineBasicMaterial,
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Vector3
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} from 'three';
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const _v1 = new Vector3();
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const _v2 = new Vector3();
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class VertexTangentsHelper extends LineSegments {
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constructor( object, size = 1, color = 0x00ffff ) {
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const geometry = new BufferGeometry();
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const nTangents = object.geometry.attributes.tangent.count;
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const positions = new Float32BufferAttribute( nTangents * 2 * 3, 3 );
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geometry.setAttribute( 'position', positions );
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super( geometry, new LineBasicMaterial( { color, toneMapped: false } ) );
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this.object = object;
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this.size = size;
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this.type = 'VertexTangentsHelper';
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//
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this.matrixAutoUpdate = false;
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this.update();
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}
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update() {
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this.object.updateMatrixWorld( true );
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const matrixWorld = this.object.matrixWorld;
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const position = this.geometry.attributes.position;
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//
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const objGeometry = this.object.geometry;
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const objPos = objGeometry.attributes.position;
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const objTan = objGeometry.attributes.tangent;
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let idx = 0;
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// for simplicity, ignore index and drawcalls, and render every tangent
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for ( let j = 0, jl = objPos.count; j < jl; j ++ ) {
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_v1.fromBufferAttribute( objPos, j ).applyMatrix4( matrixWorld );
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_v2.fromBufferAttribute( objTan, j );
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_v2.transformDirection( matrixWorld ).multiplyScalar( this.size ).add( _v1 );
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position.setXYZ( idx, _v1.x, _v1.y, _v1.z );
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idx = idx + 1;
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position.setXYZ( idx, _v2.x, _v2.y, _v2.z );
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idx = idx + 1;
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}
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position.needsUpdate = true;
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}
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dispose() {
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this.geometry.dispose();
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this.material.dispose();
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}
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}
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export { VertexTangentsHelper };
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