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Special Features

Blue Noise Support

This option can reduce the moiré-pattern effect on dark areas due to a very high jitter value. In general, try to reduce jitter as much as possible.

Enable it in “Shader Options” section in Volumetric Fog Manager.

You can also locate and edit CommonsURP.hlsl file and uncomment this line:

#define FOG_BLUE_NOISE

Orthographic Camera Support

Enable it in “Shader Options” section in Volumetric Fog Manager.

You can also locate and edit CommonsURP.hlsl file and uncomment this line:

#define ORTHO_SUPPORT

Fog Voids

A fog void is a circular area which is not covered by fog. Up to 8 fog voids can be applied to a fog volume. The Fog Void Manager component is responsible for sending the fog void positions and sizes to the shaders:

The Fog Void Manager sorts fog voids by distance to the Tracking Center. You can adjust the time interval for looking new fog voids.

To add a Fog Void to the scene, right click in the Hierarchy and select “Effects” -> “Volumetric Fog & Mist 2” -> Fog Void.

You can position / scale the fog void anywhere in the scene. Also, you can parent a fog void around characters so they will not be covered by fog. Fog voids can also be grouped or parented. Use the Roundness and Falloff slider of the Fog Void component to customize the appearance of each void.

Check this video for an example:

Native Lights

Enabling native lights in the volumetric fog inspector will cast spotlight, point lights and other light types on the fog, including support for shadows. If you enable this option, make sure the URP asset has additional lights/shadows enabled and that the spot/point lights have shadows enabled (if you also wish to render the shadows over the fog).
Point lights with shadows require Unity 2021.1 or later.

Point Lights

Up to 16 fast point lights can illuminate the fog volume using this option. This implementation is faster than the option to support native lights, however, this doesn’t support shadows. Also, if you enable native lights, this option won’t be available.

The Point Light Manager is responsible for sending the positions and settings of each point light to the shader.

The Point Light Manager sorts lights by distance to the Tracking Center. You can adjust the time interval for checking new point lights in the scene. You can also call TrackPointLights(true) of this component to cause an immediate refresh.

The Inscattering and Intensity are global multipliers to the point lights range and intensity respectively. The “Inside Atten” setting reduces the point light intensity when camera is very near to the point light to avoid “screen burn” effect.

Important: this option requires you to add the FogPointLight script to each point light you want to be rendered in the fog:

This script also allows you to specify custom in-scattering & intensity multipliers for each point light.

Note: fast point lights can bleed through geometry. You can enable the option “FAST_POINT_LIGHTS_OCCLUSION” editing the PointLights.cginc to force the shader to perform a depth occlusion test at the light position. This will hide the point light completely when it’s behind solid surfaces (this option affect performance).

Terrain Fitting

By default, the fog renders according to the selected shape (Sphere or Box) and the volume size. When enabling “Terrain Fit” in the profile, the fog will modify the vertical position to fit the underline terrain heightmap.

To use this feature please make sure that:

  • There’s a terrain (Unity terrain or mesh based terrain) under the fog volume.

  • The fog volume has enough size to cover the desired area of the terrain, both in horizontal extension and also from the base altitude to the desired top point of the terrain.

  • Use the Terrain Fog Height, Min Altitude and Max Altitude to customize the height range.

Check this video for an example:

Fog of War

The fog of war feature uses a color texture to control the opacity of the fog on the world. It can be used to clear / add fog at any custom position. This feature is commonly used to show which areas of the world have been visited or are visible to the player.

  • World Center / Coverage: maps the fog of war texture to the world using this center and size.

  • Texture Size: the size of the fog of war texture. A big texture allows finer details but it can result in a slower operation.

  • Restore Delay / Duration: controls when the fog restores it original appearance. It can be used to allow the fog to disappear while the character is at certain position and gracefully restore the fog when character abandons the place. A delay of 0 means the fog won’t never be restored. A duration of 0 means immediate change (no transtition).

  • Border Smoothness: controls the smoothness of the border of clear areas.

  • Blur: produces a softer transition between clear and opaque fog areas.

Fog of War Editor

Enable the Fog of War Editor to interactively add, paint with color or remove fog in Scene View.

Click “Create new Mask Texture” to create the texture asset which will hold the opacity states of the fog of war.

The Brush Mode selects the paint/erase mode as well as Width, Fuzziness and Opacity allow you to customize the artistic result.

Transparency support

Customizing the rendering order

Each Volumetric Fog volume can have a different render queue setting, located in “Rendering Section”:

These settings allow you to control the rendering order.

Respecting other transparent objects

The fog effect relays on the depth buffer to compute ray marching distance (that’s why you need to enable “Depth Texture” checkbox in the URP asset). Since transparent objects do not render to depth buffer, it means the fog effect will always render on top (or behind) of previously rendered objects depending on the render queue (for example water, rivers and any other transparent objects located between the fog and the camera may look incorrect either fully visible on top of the fog or completely wiped by the fog).

To avoid this issue, you should first try solving the issue by customizing the rendering order (see previous section). You can change the rendering order of Volumetric Fog volume or change the rendering order of the transparent material so one renders before the other.

Alternatively, you can force a custom depth pre-pass for certain transparent objects from the Volumetric Fog Manager inspector. There’re two ways that can be combined: transparent and alpha clipping.

  1. Transparent Objects”: specify which transparent layers should be included in the depth pre-pass and be considered completely opaque. This option is designed for ocean, lakes and rivers where the surface should behave like ground with respect to the fog.

  2. Alpha Clipping Objects”: for other kind of semi-transparent objects, like fur and hair. Increase the Alpha CutOff value.

Important note 1: These two options require installing the Depth Render Pre-Pass Feature in the Forward Renderer of the Universal Rendering Pipeline asset. Simply go to Project Settings -> Graphics -> Double click on the Universal Pipeline asset -> Double click on the Forward Renderer asset -> Add the “DepthRenderPrePassFeature” to the list:

Important note 2: when enabling “Alpha Clipping Objects” option, the asset will find which objects are contained in this layer during start. If you create new objects in this layer at runtime, call VolumetricFog.FindAlphaClippingObjects() from a script to update the internal list of objects.

Volume fade in/out and Sub-Volume support

Fading in/out the fog volume

Enable the “Fade” option in the inspector to make the fog volume invisible when the controller is outside the fog volume and make the fog appear smoothly as it enters the volume:

The Fade Controller is usually the player camera or the character controller.

Sub-volumes

Sub-volumes are zones that overlap a fog volume that modify the properties of the fog as the controller enters that sub-volume. For example, you may want to use a different fog density or color on certain areas of a fog volume.

To create a new sub-volume, right click in the hierarchy and select Effects -> Volumetric Fog 2 -> Fog Sub-Volume a shown in this screenshot:

Then, position and scale the new sub-volume using the transform position/scale anywhere in the scene, and assign the desired new profile for that sub-volume and a blending or fade distance:

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