Mist

Mist is a fog rendering package for Unity 6 and the Universal Render Pipeline. Its implementation is based on HDRP's fog system, adapted and heavily optimized for URP's rendering architecture and performance requirements. The package provides height fog, atmospheric scattering, lit volumetric fog, bounded local fog volumes, and optional screen-space multiple scattering. It is implemented entirely through URP Render Graph and supports the Universal Renderer's Forward, Forward+, Deferred, and Deferred+ paths. Documentation Core Features - Height fog and atmospheric scattering with configurable attenuation distance, base and maximum height, start distance, and maximum range. Fog color can use a constant HDR color, the active skybox, or a custom cubemap. - Froxel-based volumetric fog with directional, point, and spot-light contribution, shadows, anisotropic scattering, emission, and global illumination from Adaptive Probe Volumes or the ambient probe. - Per-light volumetric overrides for intensity, shadow strength, fade distance, source radius, and temporal evaluation. Rapidly changing lights can be evaluated from the current frame rather than accumulated into reprojection history. - Local fog volumes using oriented box or ellipsoid shapes, interior and radial fades, camera-distance fading, priority, and Overwrite, Additive, Multiply, Min, Max, or Subtractive blending. - 3D texture masks with independent tiling and scrolling. - Fog Volume Shader Graph target for procedural or texture-driven local density and scattering color. - Transparent Shader Graph integration for URP Lit and Unlit materials. A manual Shader Graph node and an HLSL helper are included for custom transparent shaders. - Screen-space multiple scattering for approximating secondary scattering behind dense fog. - Configurable denoising using temporal reprojection, Gaussian filtering, both methods, or neither. Reprojection includes history rejection and automatic invalidation after camera cuts, projection changes, frame discontinuities, and froxel-layout changes. Quality and Performance Mist includes Mobile, VR, Balanced, Quality, and Cinematic presets for common performance targets. A Balance mode provides a single quality control, while Manual mode exposes the volumetric buffer resolution and depth-slice count directly. Volumetric distance, light evaluation, denoising, and local-volume resolution can be adjusted independently. Projects that only need height fog can leave volumetric fog disabled, and projects that do not need point or spot lights in the fog can restrict lighting to directional lights. Diagnostics Mist adds a panel to Unity's Rendering Debugger with views for raw integration, temporal and filtered lighting, final fog, extinction, punctual lights, local-volume contribution and IDs, froxel layout, and effective light radius. Scene-view gizmos display volume bounds, blend regions, mask flow, volume slots, and volumetric-light radii. Runtime diagnostics expose active buffer dimensions, memory estimates, light and volume counts, and quality settings. Included Samples The Volumetric Package Manager sample contains a demonstration scene, reusable prefabs, 3D textures, and Shader Graph examples. - Ground smoke and procedural fumes - Local cloud-like fog - Animated texture-masked fog - Point-lit fog volumes - Volume blending modes - Procedural and math-only volume shapes - Screen-space multiple scattering Requirements and Platform Notes - Unity `6000.3` - Universal Render Pipeline Volumetric fog requires compute shaders, 3D textures, and `R16G16B16A16_SFloat` 3D texture load/store support. When those capabilities are unavailable, Mist skips volumetric rendering while retaining height fog. URP Compatibility Mode and the 2D Renderer are not supported. OpenGLES is not a target path for volumetric fog; mobile volumetric rendering requires suitable Metal or Vulkan hardware. Mist includes XR-aware texture access and targets single-pass XR rendering.