Experimental Feature: Area Lights

[Cameron-Micka]

Overview

This change introduces a new experimental light type called an AreaLight - area lights allow light to emit from a polygonal surface (quad) rather than a single point. The technique is based off Unity's Adam Demo solution which is based off of this research.

This solution works with the built in or URP's forward renderer. Only two area lights can be rendered at a time, but more than two lights can be added to a scene and the system will automatically cull the least important lights. Area lights are preview-able at edit time just like normal Unity lights.

The AreaLightCookieFilter is a utility component to help "blur" the cookie for an area light. This is helpful for scenarios where the area light's cookie isn't pre-filtered (like a video texture). The AreaLightCookieFilter only works at runtime.

This change also includes a new sample to preview how AreaLights look and behave.

Tested in editor, and Windows, WebGL, and Android (Quest 2) player builds.

Note, AreaLights do not currently work with the Graphics Tools/Standard and Graphics Tools/Standard Canvasshaders while performance is evaluated. Examples of how to useAreaLight`s with handwritten shaders and shader graph shaders are included in the sample scene.

Verification

As a reviewer, it is possible to check out this change locally by using the following
commands (substituting {PR_ID} with the ID of this pull request):

git fetch origin pull/{PR_ID}/head:name_of_local_branch

git checkout name_of_local_branch

[Copilot]

Pull Request Overview

Experimental Area Lights feature introduced to enable area light rendering with associated cookie filtering and editor visualization improvements. Key changes include:

• A new AreaLightInspector for visualizing and interacting with area lights in the editor.
• An AreaLightCookieFilter component that applies dual blurring to area light cookie textures.
• Added OnDrawGizmos implementations for various light types and extended AcrylicLayer with an ApplyDualBlur method.

Reviewed Changes

Copilot reviewed 42 out of 56 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
com.microsoft.mrtk.graphicstools.unity/Editor/Experimental/AreaLight/AreaLightInspector.cs	New inspector for experimental area light with scene visualization.
com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/AreaLightCookieFilter.cs	New component to filter cookie textures using dual blurring.
com.microsoft.mrtk.graphicstools.unity/Runtime/Lighting/ProximityLight.cs	Added editor gizmo drawing for proximity lights.
com.microsoft.mrtk.graphicstools.unity/Runtime/Lighting/DistantLight.cs	Added editor gizmo drawing for distant (directional) lights.
com.microsoft.mrtk.graphicstools.unity/Runtime/Lighting/HoverLight.cs	Added editor gizmo drawing for hover lights.
com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/Acrylic/Scripts/AcrylicLayer.cs	Extended with a new ApplyDualBlur method for dual blur functionality.

Files not reviewed (14)

• com.microsoft.mrtk.graphicstools.unity/Editor/Experimental/AreaLight.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Editor/Experimental/AreaLight/AreaLightInspector.cs.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/AreaLight.cs.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/AreaLightCookieFilter.cs.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/AreaLightLUTDisneyDiffuse.cs.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/AreaLightLUTGGX.cs.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/Shaders.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/Shaders/AreaLight.hlsl: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/Shaders/AreaLight.hlsl.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/Shaders/AreaLightSubGraph.shadersubgraph.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/Shaders/AreaLightVisualize.shader: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/Shaders/AreaLightVisualize.shader.meta: Language not supported
• com.microsoft.mrtk.graphicstools.unity/Samples~/AreaLight.meta: Language not supported

Comments suppressed due to low confidence (2)

com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/AreaLightCookieFilter.cs:121

• Consider checking that 'cookie' is assigned before accessing its width to avoid potential runtime errors.

int width = cookie.width;

com.microsoft.mrtk.graphicstools.unity/Runtime/Experimental/AreaLight/AreaLightCookieFilter.cs:209

• [nitpick] Consider using named arguments or adding inline comments for the constructor parameters to improve clarity and readability.

layer = new(null, null, 0, 0, true, null, cookieFilterMaterial);