three-stdlib/csm/CSMFrustum.js

stand-alone library of threejs examples

import { Vector3, Matrix4 } from "three";
const inverseProjectionMatrix = /* @__PURE__ */ new Matrix4();
class CSMFrustum {
  constructor(data) {
    data = data || {};
    this.vertices = {
      near: [new Vector3(), new Vector3(), new Vector3(), new Vector3()],
      far: [new Vector3(), new Vector3(), new Vector3(), new Vector3()]
    };
    if (data.projectionMatrix !== void 0) {
      this.setFromProjectionMatrix(data.projectionMatrix, data.maxFar || 1e4);
    }
  }
  setFromProjectionMatrix(projectionMatrix, maxFar) {
    const isOrthographic = projectionMatrix.elements[2 * 4 + 3] === 0;
    inverseProjectionMatrix.copy(projectionMatrix).invert();
    this.vertices.near[0].set(1, 1, -1);
    this.vertices.near[1].set(1, -1, -1);
    this.vertices.near[2].set(-1, -1, -1);
    this.vertices.near[3].set(-1, 1, -1);
    this.vertices.near.forEach(function(v) {
      v.applyMatrix4(inverseProjectionMatrix);
    });
    this.vertices.far[0].set(1, 1, 1);
    this.vertices.far[1].set(1, -1, 1);
    this.vertices.far[2].set(-1, -1, 1);
    this.vertices.far[3].set(-1, 1, 1);
    this.vertices.far.forEach(function(v) {
      v.applyMatrix4(inverseProjectionMatrix);
      const absZ = Math.abs(v.z);
      if (isOrthographic) {
        v.z *= Math.min(maxFar / absZ, 1);
      } else {
        v.multiplyScalar(Math.min(maxFar / absZ, 1));
      }
    });
    return this.vertices;
  }
  split(breaks, target) {
    while (breaks.length > target.length) {
      target.push(new CSMFrustum());
    }
    target.length = breaks.length;
    for (let i = 0; i < breaks.length; i++) {
      const cascade = target[i];
      if (i === 0) {
        for (let j = 0; j < 4; j++) {
          cascade.vertices.near[j].copy(this.vertices.near[j]);
        }
      } else {
        for (let j = 0; j < 4; j++) {
          cascade.vertices.near[j].lerpVectors(this.vertices.near[j], this.vertices.far[j], breaks[i - 1]);
        }
      }
      if (i === breaks.length - 1) {
        for (let j = 0; j < 4; j++) {
          cascade.vertices.far[j].copy(this.vertices.far[j]);
        }
      } else {
        for (let j = 0; j < 4; j++) {
          cascade.vertices.far[j].lerpVectors(this.vertices.near[j], this.vertices.far[j], breaks[i]);
        }
      }
    }
  }
  toSpace(cameraMatrix, target) {
    for (let i = 0; i < 4; i++) {
      target.vertices.near[i].copy(this.vertices.near[i]).applyMatrix4(cameraMatrix);
      target.vertices.far[i].copy(this.vertices.far[i]).applyMatrix4(cameraMatrix);
    }
  }
}
export {
  CSMFrustum
};
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