Custom Shader Rendering is a fully modular post-process and rendering pipeline inside Unreal Engine built using C++, HLSL, and the global shader system. It supports runtime toggles, full view extension injection, and pixel shader effects.

• Created reusable shader modules and view extensions.
• Injected post-process passes using render graph (FRDGBuilder).
• Processed scene textures like color, depth, and stencil in .usf shaders.
• Tested dynamic effects with runtime actor toggling.

Technologies Used

• Unreal Engine
• HLSL
• Global Shaders
• Visual Studio

Key Components

• MyCustomShader.usf: Post-process HLSL logic with time and UV-based color control.
• MyCustomRenderingPass.cpp: Render graph injection point using AddPass().
• MyViewExtension.cpp: Handles injection into UE's rendering flow.
• MyCharacter.cpp: Runtime control and debug of effect logic.

Use Cases

• 🔦 Lens Flares — bloom-style overlays from light sources
• 🧼 Filters — blur, chromatic aberration, or edge detection
• 🕶 Stylized Renders — outlines, toon shading, retro filters
• 🧬 Visualization — view buffers like normals, velocities

Challenges and Solutions

• Challenge: Shader injection without engine overrides
  Solution: Used View Extensions and Render Graphs to register non-destructively
• Challenge: Compatibility with packaged builds
  Solution: Global shader registration through proper module startup hooks

Shader Snippet

Sample pixel shader logic from a custom pass:

float3 SceneColor = SceneTextureLookup(UV, 0).rgb;
float3 SceneNormal = SceneTextureLookup(UV, 8).rgb;
float3 SceneDepth = SceneTextureLookup(UV, 1).rrr;

// Generate screen-space outlines by comparing normals
float3 N1 = normalize(SceneNormal);
float3 N2 = normalize(SceneTextureLookup(UV + float2(1.0/ViewportSize.x, 0), 8).rgb);
float Outline = step(0.1f, distance(N1, N2));

// Time-based pulse effect on glow
float Pulse = 0.5 + 0.5 * sin(GlobalTimeVec4.x * 4.0);
float3 Glow = Pulse * float3(1.0, 0.6, 0.1);

// Combine everything
float3 FinalColor = lerp(SceneColor, Glow, Outline);
return float4(FinalColor, 1.0);