65 lines
1.7 KiB
JavaScript
65 lines
1.7 KiB
JavaScript
import * as THREE from 'three';
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class TaperedLink extends THREE.Group {
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constructor(baseMaterial, n1, n2, r1, r2) {
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super();
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const geometry = new THREE.ConeGeometry( 0.75, 1, 32, true );
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const cplane = new THREE.Plane(new THREE.Vector3(0, -1, 0), 0.5);
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const material = baseMaterial.clone();
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material.clippingPlanes = [ cplane ];
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this.cone = new THREE.Mesh( geometry, material );
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this.add( this.cone );
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this.update(n1, n2, r1, r2);
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}
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update(n1, n2, r1, r2) {
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const kraw = r1 - r2;
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let k = ( kraw == 0 ) ? 0.001 : kraw;
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let nbase = n1.v3;
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let napex = n2.v3;
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let rbase = r1;
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let rapex = r2;
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if( k < 0 ) {
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nbase = n2.v3;
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napex = n1.v3;
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rbase = r2;
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rapex = r1;
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k = -k;
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}
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// FIXME - the problem is that when the h_offset > 1, the centroid
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// of the cone is on the other side of napex, so it looks the wrong way
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const l = nbase.distanceTo(napex);
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const h = l * rbase / k;
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const h_offset = 0.5 * h / l;
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const pos = new THREE.Vector3();
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if( l > 0 ) {
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pos.lerpVectors(nbase, napex, h_offset);
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}
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if( h_offset < 1 ) {
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this.cone.scale.copy(new THREE.Vector3(rbase, h, rbase));
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} else {
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// you're on the other side of napex so flip the cone
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this.cone.scale.copy(new THREE.Vector3(rbase, -h, rbase));
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}
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this.lookAt(napex);
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this.position.copy(pos);
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this.cone.rotation.x = Math.PI / 2.0;
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const clipnorm = new THREE.Vector3();
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clipnorm.copy(napex);
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clipnorm.sub(nbase);
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clipnorm.negate();
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clipnorm.normalize();
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this.cone.material.clippingPlanes[0].setFromNormalAndCoplanarPoint(
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clipnorm, napex
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);
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}
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}
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export { TaperedLink };
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