resources/particles/explosion.json

{
   "MaxCount": 32,
   "Duration": 1,
   "Rate": 8,
   "Drawable": {
      "Type": "SkImageDrawable",
      "Path": "resources/images/explosion_sprites.png",
      "Columns": 4,
      "Rows": 4
   },
   "Code": [
      "// float rand; Every read returns a random float [0 .. 1)",
      "layout(ctype=float) in uniform float dt;",
      "layout(ctype=float) in uniform float effectAge;",
      "",
      "struct Particle {",
      "  float  age;",
      "  float  lifetime;",
      "  float2 pos;",
      "  float2 dir;",
      "  float  scale;",
      "  float2 vel;",
      "  float  spin;",
      "  float4 color;",
      "  float  frame;",
      "};",
      "",
      "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;",
      "  p.pos = circle() * 60;",
      "  p.vel = p.pos / 3;",
      "}",
      "",
      "void update(inout Particle p) {",
      "  p.frame = p.age;",
      "}",
      ""
   ],
   "Bindings": []
}