resources/particles/sprite_frame.json

{
   "MaxCount": 32,
   "Drawable": {
      "Type": "SkImageDrawable",
      "Path": "images",
      "Name": "explosion_sprites.png",
      "Columns": 4,
      "Rows": 4
   },
   "EffectCode": [
      "void effectSpawn(inout Effect effect) {",
      "  effect.rate = 8;",
      "}",
      ""
   ],
   "Code": [
      "float2 circle() {",
      "  float x;",
      "  float y;",
      "  do {",
      "    x = rand * 2 - 1;",
      "    y = rand * 2 - 1;",
      "  } while (x*x + y*y > 1);",
      "  return float2(x, y);",
      "}",
      "",
      "void spawn(inout Particle p) {",
      "  p.lifetime = 1.0 + rand * 2.0;",
      "  float2 ofs = circle() * 60;",
      "  p.pos += ofs;",
      "  p.vel = ofs / 3;",
      "}",
      "",
      "void update(inout Particle p) {",
      "  p.frame = p.age;",
      "}",
      ""
   ],
   "Bindings": []
}