Type Alias Expr

Type Declaration

• { kind: "constF32"; value: number }
• { kind: "constVec2"; value: [number, number] }
• { kind: "constVec3"; value: [number, number, number] }
• { kind: "constVec4"; value: [number, number, number, number] }
• { kind: "attribute"; attr: ParticleAttribute }

  Reads a particle attribute. Type matches the attribute (see ParticleAttribute).

• { kind: "time" }

  Reads the engine time uniform (uniforms.time, seconds since pass start).

• { kind: "deltaTime" }

  Reads the per-frame delta-time uniform (uniforms.dt, seconds).

• { kind: "particleId" }

  Reads the particle's slot index as an f32 (handy as a per-particle constant).

• { kind: "emitterOrigin" }

  Reads the emitter origin (world-space, after the GameObject transform). vec3.

• { kind: "random"; mode: RandomMode; min: number; max: number; seed: number }

  Uniform random float in [min, max]. Seed source depends on RandomMode.

• { kind: "variable"; name: string }

  Reference to a local variable declared in the same graph.

• { kind: "unary"; op: UnaryOp; arg: Expr }
• { kind: "binary"; op: BinaryOp; lhs: Expr; rhs: Expr }
• { kind: "clamp"; value: Expr; min: Expr; max: Expr }
• { kind: "mix"; a: Expr; b: Expr; t: Expr }
• { kind: "smoothstep"; edge0: Expr; edge1: Expr; x: Expr }
• { kind: "select"; cond: Expr; whenTrue: Expr; whenFalse: Expr }

  Branchless selection: returns whenTrue if cond is true, else whenFalse. Both branches are evaluated; for control-flow use action.if_.

• { kind: "vec2"; x: Expr; y: Expr }
• { kind: "vec3"; x: Expr; y: Expr; z: Expr }
• { kind: "vec4"; x: Expr; y: Expr; z: Expr; w: Expr }
• { kind: "swizzle"; arg: Expr; channels: string }

  WGSL swizzle: swizzle(v, 'xz'), swizzle(c, 'rgb'), etc. channels must be 1–4 of [xyzwrgba].