Procedural and UV nodes in a shader graph

Five nodes that produce a pattern or move a coordinate, without a texture.

Each one is a call, not an implementation. The functions live in Raven/Library/Material/ComputeColor.rvn, whose header describes itself as "the shader-graph node vocabulary: the primitives a visual material graph compiles down to". So a node adds no shader code, CheckShaders already compiles what it calls, and the CPU has no second opinion about what noise is.

Leave the UV port unwired and the node uses the mesh's own coordinate. An unconnected port carries the literal its default made, which is not a coordinate — so every node here asks the emitter for the stage's UV instead. Wire Vector/Tiling and Offset or Vector/Rotate UV in front when you want something else.

Scale is cells across, not a multiplier on the output. Procedural/Noise at a scale of 1 is one noise cell over the whole UV square, which reads as a very slow gradient rather than as noise.

Fractal noise's Octaves is rounded down and clamped to at least one. It is a port like the others because a wire carries a float; the cast to int happens in the emitted call rather than in the library, so a library function never has to round somewhere an author cannot see.

⚠ Vector/Flipbook counts rows from the top, matching the engine's top-left UV origin. That flip is the part that is easy to get wrong and invisible until an animation plays backwards vertically.

⚠ They have no preview thumbnail, and it is the preview's limit rather than theirs. ShaderGraphPreviewRenderer compiles the emitted preview through RavenEffectCompiler.FromSources with exactly one source, so nothing in the shipped shader library is in scope and a call into ComputeColor does not bind. The same graph compiles as a material perfectly well, because EditorEffects and the shader build both hand Raven the library's import closure. See Shader-graph preview thumbnails.

⚠ There is no Perlin, simplex or voronoi node. Each of those is a function ComputeColor does not have, so adding one is a change to a published .rvn — a regeneration and a CheckShaders run — rather than a node. Value noise is what the library chose, and it says why: a hash and a smoothstep, fed into a ramp, is where the difference in gradient quality stops surviving. A gradient between two values is Math/Lerp.

A graph emits one of two shapes, and they disagreed about imports.

A surface graph writes the four Vixen.Shaders.* packages unconditionally — it is composed into a pass that has them. A standalone graph wrote none at all, which is right for the thing that compiles one: the node preview binds a single uniform block and refuses any variant whose reflection asks for more.

So a node asks, through RavenEmitter.Import, and the compiler writes only what was asked for. A graph with no procedural node in it emits no import line, and the surface shape drops a request that duplicates one of its four, because Raven refuses a repeated import.

A slow drift of colour across a surface, with no texture bound at all:

Turning a coordinate before it is sampled, which is what a rotating pattern actually is:

⚠ Both leave the UV port unwired, so both take the mesh's own coordinate. Wiring Vector/Tiling and Offset in front is how you change that — a literal on the port is not a coordinate.

• A material that draws with a graph — where the emitted surface goes, and why only one of the two graph shapes can be drawn.
• Shader-graph preview thumbnails — why these five have no preview, which is the preview's limit and not theirs.