@openhps/core/dist/esm/three/nodes/lighting/SpotLightNode.js

Open Hybrid Positioning System - Core component

import AnalyticLightNode from './AnalyticLightNode.js';
import { getDistanceAttenuation } from './LightUtils.js';
import { uniform } from '../core/UniformNode.js';
import { smoothstep } from '../math/MathNode.js';
import { renderGroup } from '../core/UniformGroupNode.js';
import { lightTargetDirection, lightProjectionUV } from '../accessors/Lights.js';
import { texture } from '../accessors/TextureNode.js';

/**
 * Module for representing spot lights as nodes.
 *
 * @augments AnalyticLightNode
 */
class SpotLightNode extends AnalyticLightNode {
  static get type() {
    return 'SpotLightNode';
  }

  /**
   * Constructs a new spot light node.
   *
   * @param {?SpotLight} [light=null] - The spot light source.
   */
  constructor(light = null) {
    super(light);

    /**
     * Uniform node representing the cone cosine.
     *
     * @type {UniformNode<float>}
     */
    this.coneCosNode = uniform(0).setGroup(renderGroup);

    /**
     * Uniform node representing the penumbra cosine.
     *
     * @type {UniformNode<float>}
     */
    this.penumbraCosNode = uniform(0).setGroup(renderGroup);

    /**
     * Uniform node representing the cutoff distance.
     *
     * @type {UniformNode<float>}
     */
    this.cutoffDistanceNode = uniform(0).setGroup(renderGroup);

    /**
     * Uniform node representing the decay exponent.
     *
     * @type {UniformNode<float>}
     */
    this.decayExponentNode = uniform(0).setGroup(renderGroup);
  }

  /**
   * Overwritten to updated spot light specific uniforms.
   *
   * @param {NodeFrame} frame - A reference to the current node frame.
   */
  update(frame) {
    super.update(frame);
    const {
      light
    } = this;
    this.coneCosNode.value = Math.cos(light.angle);
    this.penumbraCosNode.value = Math.cos(light.angle * (1 - light.penumbra));
    this.cutoffDistanceNode.value = light.distance;
    this.decayExponentNode.value = light.decay;
  }

  /**
   * Computes the spot attenuation for the given angle.
   *
   * @param {Node<float>} angleCosine - The angle to compute the spot attenuation for.
   * @return {Node<float>} The spot attenuation.
   */
  getSpotAttenuation(angleCosine) {
    const {
      coneCosNode,
      penumbraCosNode
    } = this;
    return smoothstep(coneCosNode, penumbraCosNode, angleCosine);
  }
  setupDirect(builder) {
    const {
      colorNode,
      cutoffDistanceNode,
      decayExponentNode,
      light
    } = this;
    const lightVector = this.getLightVector(builder);
    const lightDirection = lightVector.normalize();
    const angleCos = lightDirection.dot(lightTargetDirection(light));
    const spotAttenuation = this.getSpotAttenuation(angleCos);
    const lightDistance = lightVector.length();
    const lightAttenuation = getDistanceAttenuation({
      lightDistance,
      cutoffDistance: cutoffDistanceNode,
      decayExponent: decayExponentNode
    });
    let lightColor = colorNode.mul(spotAttenuation).mul(lightAttenuation);
    if (light.map) {
      const spotLightCoord = lightProjectionUV(light, builder.context.positionWorld);
      const projectedTexture = texture(light.map, spotLightCoord.xy).onRenderUpdate(() => light.map);
      const inSpotLightMap = spotLightCoord.mul(2.).sub(1.).abs().lessThan(1.).all();
      lightColor = inSpotLightMap.select(lightColor.mul(projectedTexture), lightColor);
    }
    return {
      lightColor,
      lightDirection
    };
  }
}
export default SpotLightNode;