Forward Shading Renderer
- "By default, Unreal Engine uses a Deferred Renderer as it provides the most versatility and grants access to more rendering features." Forward provides a faster baseline, faster passes, may be better for VR; better anti-aliasing options.
- Enable: Project Settings > Rendering > Forward Shading (restart).
- Forward supports MSAA and TAA; "in most cases, TAA is preferable because it removes both geometric aliasing and specular aliasing"; in VR head-tracking sub-pixel movement causes blur, so MSAA better. MSAA content should mitigate specular aliasing (Normal to Roughness, LODs). "using MSAA instead of TAA increases GPU frame time by about 25%". r.MSAACount.
- Performance mostly from features disabled per material (nearest reflection capture without parallax, per-vertex height fog, planar reflections opt-in). Robo Recall: ~22% faster on NVIDIA 970 GTX.
- "works by culling lights and Reflection Captures to a frustum-space grid. Each pixel in the forward pass then iterates over the lights and Reflection Captures affecting it". Stationary light dynamic shadows packed into a screen-space shadow mask (limit of 4 overlapping stationary lights).
- Supported: stationary lights, multiple reflection captures with parallax correction, planar reflections, DBuffer decals, precomputed lighting, any number of unshadowed movable lights, capsule shadows, alpha-to-coverage, instanced stereo, up to 4 overlapping shadow-casting movable lights.
- Not supported: screen space techniques (SSR, SSAO, Contact Shadows), dynamically shadowed translucency, ... No GBuffer scene texture access; fewer texture samplers (all in one shader) -> Shared Samplers.