IrradianceField

Remarks

This is the storage and sampling layer of docs/plan/19 § 3, and its defining property is that it does not know what filled it. A brick is a brick whether a compute shader traced rays into it this frame or an offline cube capture wrote it at build time. That is what lets doc 19 § 7 promise a phone and a desktop the same lighting model at different update rates: nothing above this branches on which filler ran.

Bricks come in sizes, and every one of them holds sixty-four probes. A brick of size eight covers five hundred and twelve times the volume of a brick of size one for the same memory, and its probes are eight times further apart. Refining near geometry — coarse where there is nothing to shade, fine where a wall is — is what makes the memory affordable and what makes a wall more than one probe thick, which is the only real defence against a leak.

Borders are maintained, not written. A filler fills the sixty-four probes a brick owns; SyncBorders fills the plane that stands in for its neighbour. The border is not data — it is a second copy of somebody else's data, which is why SetProbe refuses to address it.

There is no field-wide probe lattice, and there cannot be one. Two bricks of different sizes have probes at different spacings, so "the probe next door" is a question about world positions rather than about indices. Everything that walks probes — dilation, a filler — walks bricks and asks the field where a position lands.

Fields and properties (8)

• public IrradianceIndirection Indirection

  Which brick covers each cell.

• public IrradianceBrickPool Pool

  Where the bricks live.

• public BoundingBox Bounds

  The box the field covers.

• public int BrickCount

  How many bricks there are, counting a coarse one once.

• public IEnumerable<IrradianceBrick> Bricks

  Every brick, once each, in the order the indirection grid holds them.

• public Vector3 FinestProbeSpacing

  How far apart two probes of the finest brick there could be are.

• public float NormalBias

  How far off a surface a shading lookup moves, in probe spacings.

• public float ViewBias

  How far toward the camera a shading lookup moves as well, in probe spacings.

Methods (21)

• public IrradianceField(BoundingBox bounds, Int3 cells, IrradianceBrickPool? pool = null)

  Builds a field over a box, with an indirection grid and a pool for it.

• public Vector3 ProbeSpacingOf(int size)

  How far apart two neighbouring probes of a brick of a given size are.

• public bool TryAllocate(Int3 cell, int size, out IrradianceBrick brick)

  Gives a cell a brick of a given size, or answers with the one already covering it.

• public int Allocate(BoundingBox region, int size = 1)

  Gives every empty cell overlapping a box a brick of a given size.

• public int AllocateAll(int size = 1)

  Gives every empty cell of the field a brick of a given size.

• public int Refine(BoundingBox region, int size = 1)

  Subdivides every brick overlapping a box until it is no coarser than a given size.

• public int Split(Int3 cell)

  Replaces the brick covering a cell with eight of half its size.

• public bool TryMerge(Int3 cell)

  Replaces an aligned group of equal-size bricks with one of twice the size.

• public bool Release(Int3 cell)

  Takes a cell's brick away and gives the slot back.

• public void Clear()

  Empties the field of every brick.

• public BoundingBox BrickBounds(IrradianceBrick brick)

  The box a brick covers.

• public Vector3 ProbePosition(IrradianceBrick brick, int x, int y, int z)

  Where one probe of one brick is, in world space.

• public void SetProbe(IrradianceBrick brick, int x, int y, int z, IrradianceProbe probe)

  Writes one of the sixty-four probes a brick owns.

• public IrradianceProbe GetProbe(IrradianceBrick brick, int x, int y, int z)

  Reads one texel of a brick, border planes included.

• public void SyncBorders()

  Fills every brick's border planes from whatever is beyond them.

• public int Dilate(int passes = 1)

  Replaces probes nothing could fill with what their neighbours saw.

• public bool TrySample(Vector3 world, out IrradianceProbe probe)

  The probe a field holds at a world position, or nothing where no brick does.

• public bool TrySample(Vector3 world, Vector3 normal, out IrradianceProbe probe)

  The probe a surface sees, biased off the surface it stands on.

• public bool TrySample(Vector3 world, Vector3 normal, Vector3 view, out IrradianceProbe probe)

  The probe a surface sees, biased off the surface and toward the eye.

• public Vector3 Irradiance(Vector3 world, Vector3 normal)

  The diffuse lighting a surface at a position receives, divided by π.

• public Vector3 Irradiance(Vector3 world, Vector3 normal, Vector3 view)

  The same, for a caller that knows where the camera is.

Used by (33)

• ArenaThirdPersonShooter
• CapturedIrradianceFillerVixen.Rendering
• CapturedIrradianceFillerTestsVixen.Rendering.Tests
• CompositorAssetTestsVixen.Rendering.Tests
• CompositorBuilderVixen.Rendering
• IndirectDiffuseImageTestsVixen.Graphics.Golden.Tests
• IrradianceBounceDeviceTestsVixen.Graphics.Golden.Tests
• IrradianceBrickCursorVixen.Rendering.IrradianceFields
• IrradianceCaptureDeviceTestsVixen.Graphics.Golden.Tests
• IrradianceCoarseningTestsVixen.Rendering.IrradianceFields.Tests
• IrradianceConvergenceTestsVixen.Rendering.IrradianceFields.Tests
• IrradianceFieldFillVixen.Rendering
• IrradianceFieldRendererVixen.Rendering
• IrradianceFieldRepairVixen.Rendering
• IrradianceFieldTestsVixen.Rendering.IrradianceFields.Tests
• IrradianceFieldTextureVixen.Rendering
• IrradianceFieldTextureTestsVixen.Rendering.Tests
• IrradianceFillDeviceTestsVixen.Graphics.Golden.Tests
• IrradianceRefinementPolicyVixen.Rendering.IrradianceFields
• IrradianceRefinementPolicyTestsVixen.Rendering.IrradianceFields.Tests
• IrradianceRefinementTestsVixen.Rendering.Tests
• IrradianceRepairDeviceTestsVixen.Graphics.Golden.Tests
• IrradianceShadingDeviceTestsVixen.Graphics.Golden.Tests
• LeakTestsVixen.Rendering.IrradianceFields.Tests
• ReflectionTraceDeviceTestsVixen.Graphics.Golden.Tests
• SamplingConventionTestsVixen.Rendering.IrradianceFields.Tests
• ScreenProbeTraceDeviceTestsVixen.Graphics.Golden.Tests
• TracedIrradianceFillerVixen.Rendering.IrradianceFields
• TracedIrradianceFillerTestsVixen.Rendering.IrradianceFields.Tests
• TracedReflectionTestsVixen.Rendering.Reflections.Tests
• TracedReflectionsVixen.Rendering.Reflections
• TracedScreenProbeGatherVixen.Rendering.ScreenProbes
• TracedScreenProbeGatherTestsVixen.Rendering.ScreenProbes.Tests