skia2/resources/particles/interp.json

{
   "MaxCount": 6000,
   "Duration": 5,
   "Rate": 2000,
   "Drawable": {
      "Type": "SkCircleDrawable",
      "Radius": 2
   },
   "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;",
      "};",
      "",
      "void spawn(inout Particle p) {",
      "  p.lifetime = 2 + (rand * 2);",
      "  p.vel.x = (30 * rand) + 50;",
      "  p.vel.y = (20 * rand) - 10;",
      "}",
      "",
      "void update(inout Particle p) {",
      "  p.color.r = p.age;",
      "  p.color.g = 1 - p.age;",
      "  float s1 = 0.5 + (1.5 * p.age);",
      "  float s2 = 1.0 + (-0.75 * p.age);",
      "  p.scale = s1 + (s2 - s1) * rand;",
      "  p.vel.y += 20.0 * dt;",
      "}",
      ""
   ],
   "Bindings": []
}