WaterRenderer

Remarks

[35 § D8](../../docs/plan/35-water.md#d8-the-surface-is-a-pass-between-lighting-and-translucency-and-its-reflections-are-l5s), and what overview § 1.9 recorded transmission / refraction as waiting for. It runs after deferred lighting and before ordinary translucency, reads a copy of the scene colour and the depth buffer, and writes back into the scene colour.

⚠ The copy is the point, not fussiness. Sampling a target a pass is also writing is undefined — not slow, not approximate — which is why § B1 called the blocker the copy rather than the pass, and why !Copy exists. Name it in Behind and put a !Copy node ahead of this one.

Integrated, not blended. Alpha blending gives a surface whose opacity is a number somebody typed; absorption over a path length gives one whose colour and opacity are both consequences of how deep it is — a shallow edge clear because the path is short, going green-blue and then black over metres because the long wavelengths go first, from one coefficient triple rather than a gradient somebody painted.

⚠ The reflection plane is doc 19 § L5's, not SSR's, and that is routing rather than compromise. Unreal's water pass classifies tiles specifically so it can run an indirect SSR draw over them, because SSR is what it has. Vixen's SSR is ⬜ and its traced reflections are ✅ — so a lake reflects a mountain that is off screen, which is the single most common reflection failure in every screen-space implementation. Leave Reflections empty and the pass compiles the variant without it.

⚠ Its alpha is the waterline mask, not an opacity. § D9's underwater composite reads it per pixel, because a camera straddling the surface needs two treatments in one frame divided by a curve a post-process volume's single per-frame weight cannot express.

Fields and properties (29)

• public required string Output

  The target it writes — the frame's scene colour.

• public required string Behind

  The copy of the frame so far, which is what is behind the water.

• public required string SceneDepth

  The opaque scene's depth, which says how far away what is behind is.

• public required string Surface

  The surface plane: device depth in r, coverage in g.

• public required string Normal

  The surface's world normal in xyz and its foam in a.

• public string Reflections

  Doc 19 § L5's plane — radiance in rgb, validity in a. Optional.

• public RenderView? View

  The view the camera matrices are derived from, or null to set them by hand.

• public Matrix4x4 InverseViewProjection

  Clip back to world, when no View supplies it.

• public Vector3 CameraPosition

  Where the camera is, which both distances are measured from.

• public Vector3 Scattering

  How much light the medium scatters out of a ray per metre, per channel.

• public Vector3 Absorption

  How much it absorbs per metre, per channel.

• public float PhaseG

  Henyey–Greenstein anisotropy. Water is forward-scattering, around 0.7.

• public Vector3 BehindScale

  § D8's scale on what is behind the water.

• public Vector3 SunColour

  The radiance the volume scatters.

• public Vector3 SunDirection

  Which way the light travels.

• public Vector3 SkyColour

  What arrives from the whole sky — the term that makes water blue rather than dark.

• public float SurfaceF0

  Water against air.

• public Vector3 FoamColour

  What foam is, where the surface plane's alpha says there is some.

• public bool Foam

  Whether foam is blended over the result at all.

• public bool Tiled

  Whether the pass runs over the screen tiles that have water in them rather than over the screen — § D8's tile classification.

• public ComputePipelineCache? Pipelines

  Where the classification's compute pipeline comes from. Null turns tiling off.

• public Int2 TileCount

  How many tiles covered the target the last time this built, or zero when untiled.

• public EffectPipelineDescriber? Modules

  Where shader modules come from. Set before the first frame that builds.

• public SamplerCache? Samplers

  Where samplers come from, shared so a frame does not exhaust the device's supply.

• public DescriptorAllocator? Allocator

  Where the pass's descriptor sets come from.

• public IGraphicsDevice? Device

  The device its pipelines and its uniform block are created on.

• public FullScreenRenderer Pass

  The pass this node is, for a host that wants to look at what it did.

• public ComputeRenderer Classification

  And the classification dispatch ahead of it, which runs only when Tiled.

• public int BuildCount

  How many frames have declared the pass.

Methods (3)

• public WaterRenderer()

  Creates the node.

• protected override void Build(GraphicsCompositor compositor, CompositorFrame frame)

  Declares this node's render-graph passes.

• public void Dispose()

  Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

Used by (3)

• WaterPassImageTestsVixen.Graphics.Golden.Tests
• WaterPassTestsVixen.Rendering.Water.Tests
• WaterRendererFactoryVixen.Rendering.Water