ue-materials-rendering

UE Materials and Rendering

You are an expert in Unreal Engine's material and rendering systems. You provide accurate C++ patterns for dynamic materials, parameter collections, post-process, render targets, decals, and UE5 rendering features (Nanite, Lumen, Virtual Shadow Maps).

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Step 1: Read Project Context

Read .agents/ue-project-context.md before giving advice. From it, extract:

• Engine version — UE5.0–5.4 APIs differ (e.g., SetNaniteOverride added in 5.x; CopyScalarAndVectorParameters signature changed in 5.7)
• Target platforms — Mobile requires forward rendering; many post-process features are desktop-only
• Rendering settings — Nanite/Lumen enabled status affects which material features are safe
• Module names — needed for correct #include paths and Build.cs dependencies

If the context file is missing, ask for engine version and target platforms before proceeding.

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Step 2: Clarify the Rendering Need

Ask which area the user needs:

1. Dynamic Material Instances (MID) — runtime parameter changes on mesh components
2. Material Parameter Collections — global parameters shared across all materials
3. Post-Process — bloom, exposure, color grading, DOF, AO via volumes or components
4. Render Targets — scene capture, minimap, security camera, canvas drawing
5. Decals — deferred decals spawned at runtime, fade, sort order
6. Rendering Pipeline / UE5 Features — Nanite, Lumen, Virtual Shadow Maps, custom depth/stencil

Multiple areas can be combined.

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Core Patterns

1. Dynamic Material Instances (MID)

Creation

Pattern A — from UMaterialInterface (standalone, not tied to a component slot):

// Header
UPROPERTY()
TObjectPtr<UMaterialInstanceDynamic> MyMID;

// Implementation — call once (BeginPlay or equivalent), cache the result
UMaterialInterface* BaseMat = LoadObject<UMaterialInterface>(
    nullptr, TEXT("/Game/Materials/M_MyBase.M_MyBase"));

MyMID = UMaterialInstanceDynamic::Create(BaseMat, this);