Threejs Temporal Surfaces

Temporal Surfaces

Choose persistent history or procedural screen-space evolution explicitly. Do

not fake accumulation with time-only noise, and do not allocate history for an

effect whose complete state is analytic in time.

Pipeline

persistent surface: input -> ping-pong state -> blur -> structure -> refraction
procedural surface: time/coverage -> analytic field -> optical normal -> refraction/blur

Read references/ping-pong-accumulation.md

for an exact frost pass graph, pointer-history channels, blur and refraction

coupling, and implementation defects that must be corrected.

Read the

touch-history frost implementation for the

previous/deposit/next state transition, reduced blur, static structures,

frost-mask composition, and two-scale refraction.

Read references/refractive-window-rain.md

and the

refractive window rain implementation

for layered static and travelling droplets, finite-difference optical normals,

background refraction, stochastic disc blur, aspect fill, and presentation.

Rules

• Separate persistent state, analytic procedural state, and scene color.
• Preserve separate visible-mask and tilt-response channels.
• Use half-float for this history path unless a measured lower format is equivalent.
• Convert per-frame history decay to frame-rate-independent decay.
• Run the two-pass scene blur at reduced resolution.
• Pre-render static procedural textures once.
• Define and test resize/reset behavior for both history targets and static targets.
• Do not route world footprints, object-UV paint, or simulation-plane wetness here; this skill is view-aligned or screen-space.

Routing boundary

Use $threejs-procedural-vfx for world- or object-space residue and particles.

Use $threejs-precipitation-surfaces for world-space rain, puddles, snow, and

weather-surface coupling. This skill owns view-aligned wet-glass optics and

screen-space persistent history.