448 lines
13 KiB
JavaScript
448 lines
13 KiB
JavaScript
// ## License
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//
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// Copyright (c) 2011 Evan Wallace (http://madebyevan.com/), under the MIT license.
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// Modified for GridApps by Stewart Allen (sa@grid.space)
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(function() {
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// dep: geo.base
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let base = self.base;
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if (base.CSG) return;
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// # class CSG
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// Holds a binary space partition tree representing a 3D solid. Two solids can
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// be combined using the `union()`, `subtract()`, and `intersect()` methods.
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class CSG {
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constructor(polygons) {
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this.polygons = polygons || [];
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}
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clone() {
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let csg = new CSG();
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csg.polygons = this.polygons.map(p=>p.clone())
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return csg;
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}
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toPolygons() {
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return this.polygons;
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}
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union(csg) {
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let a = new Node(this.clone().polygons);
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let b = new Node(csg.clone().polygons);
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a.clipTo(b);
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b.clipTo(a);
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b.invert();
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b.clipTo(a);
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b.invert();
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a.build(b.allPolygons());
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return CSG.fromPolygons(a.allPolygons());
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}
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subtract(csg) {
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let a = new Node(this.clone().polygons);
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let b = new Node(csg.clone().polygons);
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a.invert();
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a.clipTo(b);
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b.clipTo(a);
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b.invert();
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b.clipTo(a);
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b.invert();
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a.build(b.allPolygons());
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a.invert();
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return CSG.fromPolygons(a.allPolygons());
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}
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intersect(csg) {
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let a = new Node(this.clone().polygons);
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let b = new Node(csg.clone().polygons);
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a.invert();
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b.clipTo(a);
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b.invert();
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a.clipTo(b);
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b.clipTo(a);
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a.build(b.allPolygons());
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a.invert();
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return CSG.fromPolygons(a.allPolygons());
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}
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// Return a new CSG solid with solid and empty space switched. This solid is
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// not modified.
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inverse() {
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let csg = this.clone();
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csg.polygons.forEach(p=>p.flip());
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return csg;
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}
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}
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// Construct a CSG solid from a list of `Polygon` instances.
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CSG.fromPolygons = function(polygons) {
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return new CSG(polygons);
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};
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// Construct a CSG from a THREE Geometry BufferAttribute array (or similar)
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CSG.fromPositionArray = function(array) {
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let polys = [];
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for (let i=0, l=array.length; i<l; ) {
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polys.push(new Polygon([
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new Vertex(new Vector(
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array[i++],
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array[i++],
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array[i++],
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)),
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new Vertex(new Vector(
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array[i++],
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array[i++],
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array[i++],
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)),
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new Vertex(new Vector(
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array[i++],
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array[i++],
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array[i++],
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)),
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]));
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}
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return CSG.fromPolygons(polys);
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};
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CSG.computeFaceNormal = function(vA,vB,vC) {
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let cb = vC.clone().sub(vB);
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let ab = vA.clone().sub(vB);
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cb.cross(ab);
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return cb.normalize();
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};
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// # class Vector
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class Vector {
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constructor(x=0, y=0, z=0) {
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this.x=x;
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this.y=y;
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this.z=z;
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}
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copy(v){
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this.x=v.x;
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this.y=v.y;
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this.z=v.z;
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return this
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}
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clone() {
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return new Vector(this.x,this.y,this.z)
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}
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negate() {
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this.x*=-1;
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this.y*=-1;
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this.z*=-1;
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return this
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}
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add(a) {
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this.x+=a.x
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this.y+=a.y
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this.z+=a.z
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return this;
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}
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sub(a) {
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this.x-=a.x
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this.y-=a.y
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this.z-=a.z
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return this
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}
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times(a) {
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this.x*=a
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this.y*=a
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this.z*=a
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return this
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}
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dividedBy(a) {
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this.x/=a
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this.y/=a
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this.z/=a
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return this
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}
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lerp(a, t) {
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return this.add(tv0.copy(a).sub(this).times(t))
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}
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unit() {
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return this.dividedBy(this.length())
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}
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length(){
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return Math.sqrt((this.x**2)+(this.y**2)+(this.z**2))
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}
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normalize(){
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return this.unit()
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}
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cross(b) {
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let a = this;
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const ax = a.x, ay = a.y, az = a.z;
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const bx = b.x, by = b.y, bz = b.z;
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this.x = ay * bz - az * by;
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this.y = az * bx - ax * bz;
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this.z = ax * by - ay * bx;
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return this;
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}
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dot(b){
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return (this.x*b.x)+(this.y*b.y)+(this.z*b.z)
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}
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}
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//Temporaries used to avoid internal allocation..
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let tv0 = new Vector()
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let tv1 = new Vector()
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// zero normal for Vertices when none provided
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let nnn = new Vector();
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// # class Vertex
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// Represents a vertex of a polygon. Use your own vertex class instead of this
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// one to provide additional features like texture coordinates and vertex
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// colors. Custom vertex classes need to provide a `pos` property and `clone()`,
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// `flip()`, and `interpolate()` methods that behave analogous to the ones
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// defined by `CSG.Vertex`. This class provides `normal` so convenience
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// functions like `CSG.sphere()` can return a smooth vertex normal, but `normal`
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// is not used anywhere else.
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class Vertex {
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constructor(pos, normal, uv, color) {
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this.pos = new Vector().copy(pos);
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this.normal = new Vector().copy(normal || nnn);
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uv && (this.uv = new Vector().copy(uv)) && (this.uv.z=0);
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color && (this.color = new Vector().copy(color));
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}
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clone() {
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return new Vertex(this.pos,this.normal,this.uv,this.color);
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}
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// Invert all orientation-specific data (e.g. vertex normal). Called when the
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// orientation of a polygon is flipped.
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flip() {
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this.normal.negate();
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}
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// Create a new vertex between this vertex and `other` by linearly
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// interpolating all properties using a parameter of `t`. Subclasses should
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// override this to interpolate additional properties.
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interpolate(other, t) {
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return new Vertex(this.pos.clone().lerp(other.pos, t),this.normal.clone().lerp(other.normal, t),this.uv&&other.uv&&this.uv.clone().lerp(other.uv, t), this.color&&other.color&&this.color.clone().lerp(other.color,t))
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}
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}
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// # class Plane
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// Represents a plane in 3D space.
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class Plane {
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constructor(normal, w) {
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this.normal = normal;
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this.w = w;
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}
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clone() {
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return new Plane(this.normal.clone(),this.w);
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}
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flip() {
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this.normal.negate();
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this.w = -this.w;
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}
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// Split `polygon` by this plane if needed, then put the polygon or polygon
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// fragments in the appropriate lists. Coplanar polygons go into either
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// `coplanarFront` or `coplanarBack` depending on their orientation with
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// respect to this plane. Polygons in front or in back of this plane go into
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// either `front` or `back`.
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splitPolygon(polygon, coplanarFront, coplanarBack, front, back) {
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const COPLANAR = 0;
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const FRONT = 1;
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const BACK = 2;
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const SPANNING = 3;
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// Classify each point as well as the entire polygon into one of the above
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// four classes.
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let polygonType = 0;
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let types = [];
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for (let i = 0; i < polygon.vertices.length; i++) {
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let t = this.normal.dot(polygon.vertices[i].pos) - this.w;
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let type = (t < -Plane.EPSILON) ? BACK : (t > Plane.EPSILON) ? FRONT : COPLANAR;
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polygonType |= type;
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types.push(type);
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}
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// Put the polygon in the correct list, splitting it when necessary.
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switch (polygonType) {
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case COPLANAR:
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(this.normal.dot(polygon.plane.normal) > 0 ? coplanarFront : coplanarBack).push(polygon);
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break;
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case FRONT:
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front.push(polygon);
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break;
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case BACK:
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back.push(polygon);
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break;
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case SPANNING:
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let f = []
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, b = [];
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for (let i = 0; i < polygon.vertices.length; i++) {
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let j = (i + 1) % polygon.vertices.length;
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let ti = types[i]
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, tj = types[j];
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let vi = polygon.vertices[i]
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, vj = polygon.vertices[j];
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if (ti != BACK)
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f.push(vi);
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if (ti != FRONT)
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b.push(ti != BACK ? vi.clone() : vi);
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if ((ti | tj) == SPANNING) {
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let t = (this.w - this.normal.dot(vi.pos)) / this.normal.dot(tv0.copy(vj.pos).sub(vi.pos));
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let v = vi.interpolate(vj, t);
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f.push(v);
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b.push(v.clone());
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}
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}
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if (f.length >= 3)
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front.push(new Polygon(f,polygon.shared));
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if (b.length >= 3)
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back.push(new Polygon(b,polygon.shared));
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break;
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}
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}
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}
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// `Plane.EPSILON` is the tolerance used by `splitPolygon()` to decide if a
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// point is on the plane.
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Plane.EPSILON = 1e-5;
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Plane.fromPoints = function(a, b, c) {
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let n = tv0.copy(b).sub(a).cross(tv1.copy(c).sub(a)).normalize()
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return new Plane(n.clone(),n.dot(a));
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};
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// # class Polygon
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// Represents a convex polygon. The vertices used to initialize a polygon must
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// be coplanar and form a convex loop. They do not have to be `Vertex`
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// instances but they must behave similarly (duck typing can be used for
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// customization).
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//
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// Each convex polygon has a `shared` property, which is shared between all
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// polygons that are clones of each other or were split from the same polygon.
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// This can be used to define per-polygon properties (such as surface color).
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class Polygon {
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constructor(vertices, shared) {
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this.vertices = vertices;
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this.shared = shared;
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this.plane = Plane.fromPoints(vertices[0].pos, vertices[1].pos, vertices[2].pos);
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}
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clone() {
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return new Polygon(this.vertices.map(v=>v.clone()),this.shared);
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}
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flip() {
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this.vertices.reverse().forEach(v=>v.flip())
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this.plane.flip();
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}
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}
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// # class Node
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// Holds a node in a BSP tree. A BSP tree is built from a collection of polygons
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// by picking a polygon to split along. That polygon (and all other coplanar
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// polygons) are added directly to that node and the other polygons are added to
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// the front and/or back subtrees. This is not a leafy BSP tree since there is
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// no distinction between internal and leaf nodes.
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class Node {
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constructor(polygons) {
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this.plane = null;
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this.front = null;
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this.back = null;
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this.polygons = [];
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if (polygons)
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this.build(polygons);
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}
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clone() {
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let node = new Node();
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node.plane = this.plane && this.plane.clone();
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node.front = this.front && this.front.clone();
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node.back = this.back && this.back.clone();
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node.polygons = this.polygons.map(p=>p.clone());
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return node;
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}
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// Convert solid space to empty space and empty space to solid space.
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invert() {
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for (let i = 0; i < this.polygons.length; i++)
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this.polygons[i].flip();
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this.plane && this.plane.flip();
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this.front && this.front.invert();
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this.back && this.back.invert();
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let temp = this.front;
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this.front = this.back;
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this.back = temp;
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}
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// Recursively remove all polygons in `polygons` that are inside this BSP tree.
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clipPolygons(polygons) {
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if (!this.plane)
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return polygons.slice();
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let front = []
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, back = [];
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for (let i = 0; i < polygons.length; i++) {
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this.plane.splitPolygon(polygons[i], front, back, front, back);
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}
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if (this.front)
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front = this.front.clipPolygons(front);
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if (this.back)
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back = this.back.clipPolygons(back);
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else
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back = [];
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//return front;
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return front.concat(back);
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}
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// Remove all polygons in this BSP tree that are inside the other BSP tree `bsp`.
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clipTo(bsp) {
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this.polygons = bsp.clipPolygons(this.polygons);
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if (this.front)
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this.front.clipTo(bsp);
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if (this.back)
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this.back.clipTo(bsp);
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}
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// Return a list of all polygons in this BSP tree.
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allPolygons() {
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let polygons = this.polygons.slice();
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if (this.front)
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polygons = polygons.concat(this.front.allPolygons());
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if (this.back)
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polygons = polygons.concat(this.back.allPolygons());
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return polygons;
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}
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// Build a BSP tree out of `polygons`. When called on an existing tree, the
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// new polygons are filtered down to the bottom of the tree and become new
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// nodes there. Each set of polygons is partitioned using the first polygon
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// (no heuristic is used to pick a good split).
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build(polygons) {
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if (!polygons.length)
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return;
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if (!this.plane)
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this.plane = polygons[0].plane.clone();
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let front = []
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, back = [];
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for (let i = 0; i < polygons.length; i++) {
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this.plane.splitPolygon(polygons[i], this.polygons, this.polygons, front, back);
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}
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if (front.length) {
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if (!this.front)
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this.front = new Node();
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this.front.build(front);
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}
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if (back.length) {
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if (!this.back)
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this.back = new Node();
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this.back.build(back);
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}
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}
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}
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// add to base objects
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base.CSG = { Solid: CSG, Vector, Vertex, Plane, Node };
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})();
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