Hi-Level/three-csg

import { Vector } from './Vector';

/**
 * Represents a vertex of a polygon. Use your own vertex class instead of this
 * one to provide additional features like texture coordinates and vertex
 * colors. Custom vertex classes need to provide a `pos` property and `clone()`,
 * `flip()`, and `interpolate()` methods that behave analogous to the ones
 * defined by `CSG.Vertex`. This class provides `normal` so convenience
 * functions like `CSG.sphere()` can return a smooth vertex normal, but `normal`
 * is not used anywhere else.
 */
export class Vertex {
  pos: Vector;
  normal: Vector;
  uv: Vector;
  color: Vector;

  constructor(pos: Vector, normal: Vector, uv: Vector, color: Vector) {
    this.pos = new Vector().copy(pos);
    this.normal = new Vector().copy(normal);
    this.uv = new Vector().copy(uv);
    this.uv.z = 0;
    color && (this.color = new Vector().copy(color));
  }

  clone(): Vertex {
    return new Vertex(this.pos, this.normal, this.uv, this.color);
  }

  // Invert all orientation-specific data (e.g. vertex normal). Called when the
  // orientation of a polygon is flipped.
  flip(): void {
    this.normal.negate();
  }

  // Create a new vertex between this vertex and `other` by linearly
  // interpolating all properties using a parameter of `t`. Subclasses should
  // override this to interpolate additional properties.
  interpolate(other: Vertex, t: number): Vertex {
    return new Vertex(
      this.pos.clone().lerp(other.pos, t),
      this.normal.clone().lerp(other.normal, t),
      this.uv.clone().lerp(other.uv, t),
      this.color && other.color && this.color.clone().lerp(other.color, t)
    );
  }
}