Generators and the compound library

A generator is a texture graph that reads what a mesh-map bake measured — curvature, occlusion, thickness — and turns it into a mask. It is the thing that makes a texturing tool feel clever: dirt in cavities is a curvature multiplied by an occlusion, and edge wear is a curvature with a threshold on it. Neither is code. Both are .vxtexgraph files.

Three pieces make that work, and they are described here because none of them is obvious from the type it lives in:

⚠ This is the whole of why one generator works on every mesh, and it is a decision about what a graph is not allowed to contain.

A texture graph carries a name, nodes, edges, an interface and the settings of the evaluation guide's § D8 — a base resolution and a seed. It carries no mesh, and adding somewhere to put one would be the bug rather than the fix: a generator that named a mesh is a generator that works on that mesh.

So the mesh enters at the evaluation, in exactly the place the bake resolution enters. A Source/Mesh Map node emits an external image whose reference is meshmap:curvature — a scheme, not a path — and a host that knows which texture set it is baking resolves that reference against the project's baked maps.

The consequence worth stating out loud is that the compiled plan is the same plan for every mesh. Two bakes of one generator differ only in their external table. "One compound, two meshes, no rewiring" is therefore not a feature the node implements; it is the only thing this shape can do — which is why the test that proves it checks the two bakes bind different files, rather than merely that both compiled.

The Map setting takes one of nine names — normal, height, ao, bent, curvature, thickness, position, world, id — which are the suffixes mesh maps as project assets writes into each map's sidecar. A name that is not one of them is a TG0010 naming the node and the setting, and not a fallback to the first: every mesh map looks like a mesh map, so a generator wired to the wrong measurement produces a plausible picture nobody would question.

Two things the node decides that no setting exposes:

• Grey or colour. height, ao, curvature and thickness are one measurement per texel and come back grey; the other five are directions, positions or indices and come back colour. A bent normal read as grey loses two thirds of itself at the first node that touches it, and a curvature read as colour is a type error at any port that measures — both are silent, in opposite directions.
• ⚠ id is point-sampled and everything else is interpolated. Interpolating two material indices produces a third that belongs to no material, so a bilinearly resampled id map grows a hairline of a fourth material along every boundary. It looks like an antialiased edge.

⚠ A quantized map arrives quantized. Displacement and curvature are stored as 0.5 + 0.5·v/range with the range in the sidecar, so curvature is a map whose 0.5 is zero curvature — edges above it, creases below. The node cannot decode it: reading the sidecar means an asset database, and a compilation runs on every edit. A Colour/Levels picking the half you want is what a generator does, and every shipped one does exactly that.

A compilation hands back what it could not fill itself, and a mesh-map reference is one of those:

MeshMapBinding.TryFor(library, model, out var binding, out var problem) is the convenience for a model with one texture set, and it refuses a model with several rather than picking one: every mesh of a model has its own curvature map, so "the curvature map of this model" has as many answers as the model has meshes.

⚠ A false with an empty problem is not a failure. A compilation's external list mixes imported bitmaps with mesh maps, and a host walks it once — so a resolver that reported Assets/Textures/rust.png as an unresolvable mesh map would make every graph containing a Source/Bitmap look broken. MeshMapReference.IsMeshMap is the same question asked before the call.

Doc 48 § D5's claim is that the several hundred nodes a reference tool ships are content, and this is the mechanism that makes it true. TextureCompoundLibrary.Publish reads two roots into one menu:

• The compounds embedded in Vixen.Editor.TextureGraph, from its Compounds/ folder — the same arrangement the kernels use, and for the same reason: there is nothing a deployment can leave behind.
• A project's own folder, if it names one, published beside them.

A file's path under the root is its node-type path, so Compounds/Generators/Dirt.vxtexgraph is the node Generators/Dirt.

⚠ A project compound whose path collides with a shipped one is refused rather than allowed to shadow it, and comes back as a TextureCompoundProblem naming both files. Overriding is what a library grows into wanting; it is also how an author's half-finished copy of Generators/Dirt silently rebinds every material that reads it.

⚠ A shipped compound's file name may not contain a dot. A manifest resource name has no way to tell a folder separator from a dot somebody typed, so Grunge v2.vxtexgraph would publish under a path with a phantom folder in it.

⚠ No number is written here, and the four that were are why. This page has said "sixteen, against the two dozen doc 48 marks" and then "thirty-one, against thirty-five", and every one of those four figures was a snapshot of the day it was typed — the first pair because fifteen more compounds had landed and § 4.9's own summary sentence miscounted its own table, the second because the folder moved again inside the week. Count them off TextureCompoundLibrary.Shipped, which is derived from the manifest, and read what is owed off TextureCompoundLibraryTests, which compares that list with § 4.9's marks by name. ⚠ A count could not have caught a mark that counts wrong, and did not — #1110 was filed against a row whose arithmetic was green either way.

⚠ Nothing is owed as of 2026-09-09 — Patterns/Scratches, Wood Grain, Cells and Surface/Metal Reflectance all shipped, and the Delight / Equalize row turned out to be one ● for one compound under two names rather than two compounds with one missing (#1110). § 4.9's marks and the folder are the same list of names, which is the form the assertion takes and the reason it is derived rather than counted. ⚠ Do not take a remainder off this paragraph either: TextureCompoundLibrary.Shipped is the derived list and TextureCompoundLibraryTests is what compares it with the plan, by name. ⚠ The measurement M10 exists to make is written up beside the content itself, in Editor/Vixen.Editor.TextureGraph/Compounds/README.md: what could not be authored out of the atomic set, which is the standing test of whether M2 and M3 got that set right.

⚠ Histogram Scan's knobs are a black and a white point, not the reference's position and contrast. That was because a compound's knob could only be a port, and a port cannot be arithmetic; it is no longer a constraint (see below) and the node keeps the two numbers it was authored with.

⚠ This section said until 2026-09-08 that only ports work, and #742 closed that. SubGraphs.Flatten replaces the sub-graph node with the graph's contents, and the node is where a parameter override is stored — so before #742 an expression inside a published graph folded against that graph's own declared default and turning the knob changed nothing. NodeGraphInlining now carries each expansion's settings and the compiler reads them, so a shipped compound declares parameters and drives node ports through folded expressions. ⚠ This sentence has carried two counts and both went stale — it read "seven of the sixteen", then "twenty-five of the thirty-one", and the tree was 29 of 35 while the second was being typed. So it is a derivation now and not a number: every shipped compound except Generators/Curvature Edge Wear · Dirt · Grunge Rough Dirty and Utility/Equalize · Highpass · Histogram Scan declares at least one, so a knob is the norm here rather than the exception, and the sentence a reader should take from this section is that a port is what you reach for when the knob has to be wired, not when it has to exist.

Which to reach for is now a real choice rather than a workaround:

* a port is an edge, so it can take a whole image and can be wired from another node; * a parameter has a group and, for the three numeric kinds, a range — so it can be arithmetic, position ± contrast/2 is expressible, and it appears in the node inspector as a knob rather than as a dangling input. ⚠ This said "a parameter is a number" and there are four kinds, not three: Scalar, Integer, Boolean and, since 2026-09-08, Name — which is substituted into a [Setting] on a node inside the published graph rather than folded into arithmetic, and is the one kind an expression cannot spell, because a name is not a number and a source that declared one would not parse.

• ⚠ This bullet said no host calls TextureCompoundLibrary.Publish, so the shipped compounds were "not in the panel's search" and a Source/Mesh Map graph "compiles and does not bake" — and every clause of it is false, re-measured 2026-09-08. TextureCompoundLibrary.Publish has two production callers: TextureNodeLibrary.Publish (Editor/Vixen.Editor.Texturing/TextureNodeLibrary.cs:138), which both documents, the compound watch and the layer-stack compiler start from, and Tools/Vixen.Cli/TextureGraphRunner.cs:105. ⚠ Not TextureNodeLibrary.Create — the two are different methods and Create registers the generated node types and deliberately publishes no compounds, which is a distinction worth keeping rather than blurring. A mesh map resolves as a meshmap: external through TextureExternalImages and bakes on a device. ⚠ A guide page telling an artist that the library they can see in the search is unreachable is a worse defect than the gap it described, and it survived two batches of the fix because nothing re-reads a page whose subject somebody else repaired.
• ⚠ What is still true, one name along: MeshMapBinding — Vixen.Editor.Assets' resolver — has no caller outside its own assembly. The plugin resolves the scheme itself and says so (TextureExternalImages.cs:49 duplicates TextureMeshMaps.Scheme deliberately, because the alternative is telling an artist that meshmap:curvature is a missing file), so this is two answers to one question rather than a missing one.
• ⚠ Two Source/Mesh Map nodes asking for one usage ask for it twice. Each allocates its own external image, so a host uploads one PNG twice. The pictures are identical, so no bake is wrong; de-duplicating means the compiler keying externals by their reference — #800.

• Mesh maps as project assets · what a bake writes, and the sidecar it leaves beside each file
• Evaluating a texture graph · the plan a compilation produces
• The texture graph plugin · the document and the panel