fourdjs/taperedLink.js
2025-11-09 17:41:37 +11:00

88 lines
2.7 KiB
JavaScript

import * as THREE from 'three';
// really stupid idea: add a cylinder as well!
class TaperedLink extends THREE.Group {
constructor(baseMaterial, n1, n2, r1, r2) {
super();
const cone = new THREE.ConeGeometry( 0.75, 1, 32, true );
const cplane = new THREE.Plane(new THREE.Vector3(0, -1, 0), 0.5);
const material = baseMaterial.clone();
material.clippingPlanes = [ cplane ];
this.cone = new THREE.Mesh( cone, material );
this.add( this.cone );
const cylinder = new THREE.CylinderGeometry(1, 1, 1, 16, 1, true);
const cyl_material = baseMaterial.clone();
cyl_material.color = new THREE.Color(0xff0000);
this.cylinder = new THREE.Mesh(cylinder, cyl_material);
this.add( this.cylinder );
this.update(n1, n2, r1, r2);
}
update(n1, n2, r1, r2) {
this.update_cone(n1, n2, r1, r2);
}
update_cone(n1, n2, r1, r2) {
const kraw = r1 - r2;
let k = ( kraw == 0 ) ? 0.001 : kraw;
let nbase = n1.v3;
let napex = n2.v3;
let rbase = r1;
let rapex = r2;
if( k < 0 ) {
nbase = n2.v3;
napex = n1.v3;
rbase = r2;
rapex = r1;
k = -k;
}
const l = nbase.distanceTo(napex);
const h = l * rbase / k;
const h_offset = 0.5 * h / l;
const pos = new THREE.Vector3();
if( l > 0 ) {
pos.lerpVectors(nbase, napex, h_offset);
}
const rmean = 0.5 * (r1 + r2);
if( h_offset < 1 ) {
this.cone.scale.copy(new THREE.Vector3(rbase, h, rbase));
this.cylinder.scale.copy(new THREE.Vector3(rmean, l, rmean));
} else {
// you're on the other side of napex so flip the cone
this.cone.scale.copy(new THREE.Vector3(rbase, -h, rbase));
this.cylinder.scale.copy(new THREE.Vector3(rmean, -l, rmean));
}
this.lookAt(napex); // the group, not the cone!!
this.position.copy(pos); // the group, not the cone!!
this.cone.rotation.x = Math.PI / 2.0;
this.cylinder.rotation.x = Math.PI / 2.0;
const clipnorm = new THREE.Vector3();
clipnorm.copy(napex);
clipnorm.sub(nbase);
clipnorm.negate();
clipnorm.normalize();
this.cone.material.clippingPlanes[0].setFromNormalAndCoplanarPoint(
clipnorm, napex
);
}
update_cylinder_busted(n1, n2, r1, r2) {
const length = n1.v3.distanceTo(n2.v3);
const centre = new THREE.Vector3();
centre.lerpVectors(n1.v3, n2.v3, 0.5);
const link_mean = (r1 + r2) * 0.5;
this.cylinder.scale.copy(new THREE.Vector3(link_mean, link_mean, length));
this.cylinder.position.copy(centre);
//this.cylinder.lookAt(n2.v3);
this.cylinder.rotation.x = Math.PI / 2.0;
}
}
export { TaperedLink };