Chapter 798: TSL Built-in Inputs & Attributes

Core Idea

TSL exposes the shader stage's implicit inputs (vertex position/normal, camera matrices, screen coordinates, time, material properties) as ready-made node constants you reference by name instead of declaring varyings/uniforms by hand.

Key Concepts

• positionLocal / positionWorld / positionView: vertex position in local, world, and view space respectively — the standard vertex-stage chain.
• normalLocal / normalWorld / normalView / normalGeometry: analogous normal-space variants; transformedNormalView/transformedNormalWorld are post-normal-mapping.
• cameraPosition / cameraViewMatrix / cameraProjectionMatrix: camera-space uniforms, auto-updated per frame.
• screenUV / screenCoordinate / screenSize: fragment-stage screen-space helpers for post-processing and full-screen effects.
• time / deltaTime / frameId: global animation clock uniforms, updated by the renderer each frame — no manual uniform wiring needed.
• materialColor / materialRoughness / materialMetalness / …: the current material's PBR properties as readable nodes, useful when writing a custom lighting model that still respects material inputs.

Reference Tables

Position / geometry pipeline

Node	Type	Space
positionGeometry	vec3	Raw geometry attribute, pre-skinning/morph
positionLocal	vec3	Local (object) space, post-skinning/morph
positionPrevious	vec3	Previous frame's local position (motion vectors)
positionWorld	vec3	World space
positionWorldDirection	vec3	Normalized world-space direction from camera
positionView	vec3	View (camera) space
positionViewDirection	vec3	Normalized view-space direction

Normal / tangent pipeline

Node	Notes
normalGeometry, normalLocal, normalView, normalWorld	Raw normal at each space, pre-normal-map
normalFlat	Face-flat normal (derivative-based)
transformedNormalView, transformedNormalWorld	Post-normal-map, what lighting should actually use
tangentGeometry, tangentLocal, tangentView, tangentWorld	Tangent vectors, mirror the normal set
bitangentGeometry/Local/View/World	Bitangent vectors

Camera / model uniforms

Node	Description
cameraPosition, cameraNear, cameraFar	Camera transform/frustum
cameraViewMatrix, cameraProjectionMatrix(Inverse), cameraWorldMatrix, cameraNormalMatrix	Camera matrices
modelPosition, modelScale, modelDirection, modelRadius	Current object's transform
modelViewMatrix, modelWorldMatrix, modelWorldMatrixInverse, modelNormalMatrix	Model transform matrices
modelViewProjection	Combined MVP, as a varying

Screen / viewport (fragment stage)

Node	Description
screenUV, screenCoordinate, screenSize, screenDPR	Full-canvas screen-space helpers
viewportUV, viewportCoordinate, viewportSize, viewport	Current viewport (may differ from screen with multiple viewports)
viewportLinearDepth	Linear (non-projective) fragment depth

Time / frame

Node	Description
time	Seconds since start, auto-updated
deltaTime	Seconds since last frame
frameId	Integer frame counter

Compute-only builtins: instanceIndex, vertexIndex, drawIndex, workgroupId, localId, globalId, subgroupIndex, subgroupSize, numWorkgroups — used inside compute shaders (WebGPURenderer compute passes), not classic vertex/fragment materials.

Anti-patterns

• Reading normalView/normalWorld for lighting instead of the transformed* variants: you'll get pre-normal-map shading, which looks flat wherever a normal map is applied.
• Assuming compute-only builtins (instanceIndex, workgroupId, etc.) work in a regular material: they're only valid inside a compute shader context.

Key Takeaways

1. There's a consistent naming pattern: <thing><Space> (position / normal / tangent × Geometry / Local / View / World) — learn the pattern once, it covers dozens of builtins.
2. Use transformed* variants for lighting-relevant normals (they account for normal mapping); use the plain *View/*World variants when you need the un-perturbed geometric normal.
3. time/deltaTime/frameId remove the need to manually create and update a uniform(0) clock every frame.
4. Compute-stage builtins (workgroupId, globalId, atomics) only make sense inside WebGPURenderer compute passes, not standard material shaders.

Connects To

• ch797 (TSL Language Basics): these constants are the typical leaves of a node graph built with Fn()/operators.
• ch799 (TSL Utility Functions): higher-level functions that consume these builtins internally (e.g. reflection/refraction helpers use positionView/normalView).
• MeshStandardNodeMaterial: exposes colorNode/normalNode/positionNode etc. as the attachment points for graphs built from these inputs.