WaterRipples

Remarks

Displacement, not geometry ([35 § D12](../../docs/plan/35-water.md#d12-ripples-are-a-sliding-window-height-field-and-they-are-displacement-not-geometry)). A texture of surface displacement and its velocity, advanced by a wave-equation step, with entities injecting into it — a character wading writes a moving depression, a boat writes a hull-shaped one, an impact writes an impulse. The result is added by WaterEvaluator, so a second boat rides the first one's wake and the buoyancy solver feels it.

⚠ This exists on the CPU even when a GPU simulation is running, and that is a stated behaviour rather than duplication. Buoyancy sampling a GPU texture cannot see the current frame's step without a stall, so the simulation is also run here at a lower resolution over the same injections — deterministic, jobbable, and compared against the device version at a stated tolerance that is not exact, unlike everything else in this assembly. That asymmetry is why the ripple contribution is separated from the wave sum in the evaluator's signature: the closed-form part is exact and the simulated part is not, and a caller that needs the exact one — the network path — asks for it alone by passing no ripples at all.

⚠ The window scrolls by shifting its contents, unlike WaterField, which forgets them. A field is a function of bodies and ground that can be recomputed; a simulation's state is its history, and throwing it away when the camera walks would delete every wake in the scene. So the shift is by whole texels — which is also why the origin snaps.

Fields and properties (6)

• public WaterRippleSettings Settings

  Its shape and its limits.

• public Vector2 Origin

  Where the window's low corner is, on the ground plane.

• public int Injections

  How many injections this step accepted.

• public int Overflowed

  How many it had to refuse, over the budget.

• public int StepCount

  How many steps have been taken.

• public float Peak

  The largest displacement anywhere in the field, in metres.

Methods (8)

• public WaterRipples(in WaterRippleSettings settings, Vector2 origin = default(Vector2))

  Creates an empty simulation.

• public void Clear()

  Forgets everything, keeping the window where it is.

• public bool Follow(Vector2 centre)

  Moves the window to follow a point, carrying the state with it.

• public bool Inject(Vector2 position, float radius, float amount)

  Adds a disturbance to the field.

• public int Apply(WaterDisturbances queue)

  Injects every disturbance a step produced.

• public void Step(float deltaTime)

  Advances the simulation by one fixed step.

• public bool TryDisplacement(Vector2 position, out float displacement)
• public float At(int x, int z)

  What the field holds at one texel, unfiltered.

Used by (5)

• WaterDebugDrawVixen.Rendering.Water
• WaterDebugDrawTestsVixen.Rendering.Water.Tests
• WaterDisturbanceTestsVixen.Water.Tests
• WaterRippleSeamTestsVixen.Graphics.Golden.Tests
• WaterRippleTestsVixen.Water.Tests