Package limn.render3d.shader

@NullMarked package limn.render3d.shader

A neutral, typed shader IR: a material's surface is a SurfaceOutputs built from Expr nodes, and a backend's code generator walks that DAG to emit its own shading language, so the toolkit ships no GLSL, and a new target means a new generator rather than new materials. StandardSurface expresses the built-in metallic-roughness surface in this IR, and is the model for writing a custom one.

Related Packages

Package	Description
limn.render3d	Render-to-texture 3D: Graphics3D is both the facade a caller uses inside a frame and the SPI the backend installs, and around it sit the neutral resources a scene is made of: MeshData and TextureData built on any thread, their uploaded twins GpuMesh and GpuTexture, Camera with its controllers, Material, Light, and the RenderPass draws are issued into.
limn.render3d.gltf	glTF 2.0 loading: GltfLoader reads .gltf or binary .glb into a neutral GltfModel of meshes, materials and node transforms (no GPU and no third-party parser), so the reading and decoding can run on a worker (the loadAsync forms are cancellable and report progress) and the upload happens later, inside a frame.
limn.render3d.scene	A retained scene over the imperative pass: Scene3D traverses a Node tree of MeshNodes and LightNodes, composes world transforms, gathers the lights, frustum-culls and issues the same draws a caller could issue by hand.

Class	Description
Expr	A node in the neutral, typed shader-expression DAG.
Expr.Binary	Binary arithmetic; result type follows GLSL scalar/vector promotion.
Expr.Call	A built-in or engine helper call with a declared result type.
Expr.Construct	A constructor like vec4(rgb, a) or vec3(x).
Expr.Lit	A numeric literal, scalar or vector by value count.
Expr.Loop	A value computed by a bounded loop: a state of one value or several, their initial values, and the state after one turn, taken at most maxIterations times.
Expr.Op	Arithmetic operators.
Expr.Raw	Non-portable inline GLSL, valid only for target.
Expr.Ref	A named value: an input the framework or the surface declares (a UBO member, a varying, a sampler, a Material.Surface input), or the state of the Expr.Loop it is read in, which Expr.Loop.of(limn.render3d.shader.Expr, int, java.util.function.Function<? super limn.render3d.shader.Expr, ? extends limn.render3d.shader.Expr>) hands the loop's turn.
Expr.Sample	Samples sampler at uv → vec4.
Expr.Swizzle	Component selection, e.g.
ShaderType	The value types the neutral shader IR works with: the GLSL scalar/vector types plus sampler2D.
StandardSurface	Builds the SurfaceOutputs for the built-in metallic-roughness material, the same surface the hand-written reference shader computes, expressed as neutral IR so one code generator can target multiple shading languages.
SurfaceOutputs	What a material's surface function contributes to the engine's lighting core: the metallic-roughness inputs.
TargetProfile	A shading-language target the IR can be compiled to.