---
title: Viewport Modes — Shader Complexity (excerpt)
source: https://dev.epicgames.com/documentation/en-us/unreal-engine/viewport-modes-in-unreal-engine
version: Unreal Engine 5.8 Documentation
fetched: 2026-10-15
note: 从 Viewport Modes 页摘录 Shader Complexity 及相关调试视图要点；非全文
---

# Shader Complexity (from Viewport Modes)

- Hotkey: Alt + 8; console: `viewmode shadercomplexity`
- Visualizes number of shader instructions used to calculate each pixel. Good for base scene performance and particle overdraw spikes.
- Caveat: only instruction count — 16 texture lookups much slower than 16 math ops on all platforms; loops not unrolled (esp. vertex shaders) not represented accurately. Still good metric in vast majority of cases.
- Colors: green→red linear inexpensive→expensive; pink/white jump to very expensive. Small white areas OK; majority bright red/white → poor performance.
- +ShaderComplexityColors in BaseEngine.ini, lerped by instruction count.
- MaxPixelShaderAdditiveComplexityCount default 2000 (override in DefaultEngine.ini); MaxES3PixelShaderAdditiveComplexityCount default 800.

## Related modes often used with materials
- Light Complexity: Alt+7 / `viewmode lightcomplexity` — non-static lights affecting geometry.
- Buffer Visualization: Base Color, Metallic, Roughness, World Normal, Shading Model, Material AO, Opacity, etc.
- Reflections mode: flat normal + roughness 0 for diagnosing reflection captures.