@polygonjs/polygonjs/dist/src/core/particles/CoreParticlesInit.js

node-based WebGL 3D engine https://polygonjs.com

"use strict";
import { BufferAttribute, InstancedBufferAttribute } from "three";
import { GlobalsTextureHandler } from "../../engine/nodes/gl/code/globals/Texture";
import { textureFromAttributePointsCount } from "../geometry/operation/TextureFromAttribute";
import { markedAsInstance } from "../geometry/GeometryUtils";
export function coreParticlesInitParticlesUVs(object, texturesSize) {
  const geometry = object.geometry;
  if (!geometry) {
    return;
  }
  const pointsCount = textureFromAttributePointsCount(geometry);
  var uvs = new Float32Array(pointsCount * 2);
  let p = 0;
  var cmptr = 0;
  for (var j = 0; j < texturesSize.x; j++) {
    for (var i = 0; i < texturesSize.y; i++) {
      uvs[p++] = i / (texturesSize.x - 1);
      uvs[p++] = j / (texturesSize.y - 1);
      cmptr += 2;
      if (cmptr >= uvs.length) {
        break;
      }
    }
  }
  const uv_attrib_name = GlobalsTextureHandler.PARTICLES_SIM_UV_ATTRIB;
  const attribute_constructor = markedAsInstance(geometry) ? InstancedBufferAttribute : BufferAttribute;
  geometry.setAttribute(uv_attrib_name, new attribute_constructor(uvs, 2));
}