Photon Shader Node Reference

Node descriptions 2.2.2

Photon nodes bring runtime particle streams, camera data, scene textures, and coordinate conversions into the graph.

Photon nodes bridge the generic graph compiler to particle instances, scene buffers, and full-screen passes.

Particle Graph Inputs

Node	Outputs	Graph/stage behavior
Particle Data	position, color, litColor, uv, normal	Particle and function graphs; usable in both stages
Additional Data	selected scalar or vec3 channel	Read in vertex, auto-varying to fragment; unsupported = zero
Custom Data	selected vec4 stream	Read in vertex, auto-varying; preview/CPU path = zero
Viewport	viewport size and screen information	Screen-dependent calculations
Depth Fade	intersection fade	Fragment; needs scene depth
World to Screen UV	screen UV from world position	Coordinate conversion
Screen to World	reconstructed world position	Fragment; needs depth/camera matrices

Particle Data.position is camera-relative world position after interpolation. color is the authored/runtime particle color; litColor includes baked light-map multiplication. Trail UV normally uses the length axis instead of sprite-frame semantics.

Additional Data Channels

The node dropdown is generated from PhotonGpuChannels, so it stays aligned with the runtime registry. Selecting a channel also marks that stream as required; Shader Graph instancing uploads it without requiring the inspector toggle. See Additional GPU Data for meanings and emitter support.

Fullscreen Graph Nodes

Node	Purpose
Fullscreen Position	Fullscreen vertex position and UV basis
Fullscreen Output	Final processed color/alpha
Texel Size	1 / renderTargetSize for neighbor samples
Scene Color/Texture input	Current graph input or named Render Graph texture
Scene Depth	Depth-based blur, outline, and reconstruction

Fullscreen-only nodes cannot be placed in a particle Shader Graph. Likewise, Particle Data has no meaning in a Fullscreen Graph.

Screen-Space Accuracy

• UV origin and depth conventions are handled by Photon nodes; avoid hard-coded flips.
• Sample neighboring pixels with Texel Size, not a fixed 1/1920 value.
• Depth is nonlinear unless a node explicitly exposes linearized depth.
• Under Iris, scene/depth availability depends on the active pipeline. Test graceful output when a buffer is absent.

TIP

Select a node and open its description panel before wiring it. Since 2.2.2, Photon nodes describe ports, stage constraints, channel types, and GLSL equivalents inside the editor.