Creating LWRP/URP Lights

Learn more about the Universal Render Pipeline here.

URP stands for “Universal Render Pipeline,” which aims to optimize real-time performance on performance-constrained platforms such as mobile devices or low-end consoles and PCs. It does this by making some tradeoffs in the lighting and shading sections of the pipeline.

If you wish to target a wide range of mobile devices, virtual reality, or are developing a project that has a limited need for real-time lighting, then using the URP will be incredibly beneficial.

Let’s start a new project with URP.

• Open Unity Hub and click the New Project button.
• In the Templates section, select Universal RP Template (Figure 02).

• Click the Create Project button.

Once that’s done, your new Unity Project with the URP will be ready to go.

To upgrade an existing project, you must first download the URP using the Unity Package Manager.

• Go to the Window dropdown and select Package Manager to open the Packages window (Figure 03).

• Click the All button on the left.
• Find Universal RP in the list and select it.
• Click install.

After the package has been installed from the Package Manager, you have to add the URP Asset to the Scriptable Render Pipeline Graphics settings field.

• Go to Edit dropdown and select Project Settings > Player.
• Set the project to Linear color space in Player Settings (Figure 04).

• Create a pipeline Asset by selecting the Asset dropdown and selecting Create > Rendering > Universal Render Pipeline > Pipeline Asset.
• Go to the Edit dropdown and select Project Settings > Graphics.
• In the Graphics Inspector, drag and drop the UniversalRenderAsset into the Scriptable Render Pipeline field. (Figure 05)

Now your existing project will use the URP.

In the URP, lights are more restricted to keep them performance-oriented and really home in on the ability to target as many platforms as possible. There are a few restrictions you should keep in mind:

• The URP has a max local light count that defaults to 1. You’ll need to select the pipeline asset and increase the number if you wish to have more than 1. If you do not do this, Directional Lights will disable all other local lights.
• Real-time indirect bounce shadowing is not supported for Spot and Point lights.
• Real-time shadows for Point lights are not supported.

With those things in mind, let’s create a Spot Light.

• From the GameObject dropdown, select Light > Point Light. Alternatively, select an existing GameObject and click Add Component to add the Light component.
• In the Light Inspector, change the Type to Spot (Figure 06).

• Type: This shows the current type of light being used. Possible values are Spot, Directional, Point, and Area (baked only).
• Range: Determines how far the light emitted from the center of the object travels. This is for Point and Spotlights only.
• Spot Angle: Determines the angle of the light. Inner percent determines where the attenuation between the inner cone and the outer cone starts. Higher values will cause the light at the edges of the Spot to fade out, while lower values will stop the light from fading at the edges.
• Color: Sets the color of the emitted light.
• Mode: This allows you to specify the Light Mode used to determine if and how light is baked. The possible modes are Realtime, Mixed, and Baked.
  • Realtime is used for lights that need to change their properties during run time.
  • Mixed is used for lights that change their transform and visual properties during the run time but with limitations.
  • Baked is used to create local ambiance and don’t change during run time.
• Intensity: This value sets the light’s brightness.
• Indirect Multiplier: This value is used to vary the intensity of indirect light. Indirect light is the light that bounces from one object to another. A value lower than 1 causes the light to dim with every bounce. Higher than 1 makes the light brighter with each bounce. Keeping it at 1 means the light remains the same with every bounce.
• Shadow Type: This setting determines whether the light casts No Shadows, Hard Shadows, or Soft Shadows.
• Baked Shadow Radius: This controls the amount of artificial softening applied to the edges of the shadows cast by the Point or Spot Lights.
• Render Mode: This setting specifies the rendering priority of the selected Light. The available settings are Auto, Important, Not Important.
  • Auto determines the render mode.
  • Important will always render the light at the per-pixel quality. Use this for the most noticeable lights.
  • Not Important will render lights with a faster method of vertex/object light mode.
• Culling Mask: Use this setting to selectively exclude groups of objects from being affected by the Light.

The Directional Light has all the same settings as the Spot Light minus Range and Spot Angle. The Baked Shadow Radius turns into Baked Shadow Angle (Figure 07).

• Baked Shadow Angle: This controls the amount of artificial softening applied to the edges of the shadows cast by Directional Lights.

Point Lights have the same settings as Spot Lights, minus the Spot Angle (Figure 08).

Much like the other lights, Area lights have similar properties as Spot and Point Lights, but with some additional settings that control the size and effects of the Light (Figure 09).

• Range: This value is computed from the width, height and intensity values.
• Width: Determines the width of the Area Light.
• Height: Determines the height of the Area Light.
• Cast Shadows: Toggle this to enable the light to cast shadows.

Lights in the URP are designed to be efficient but not impact the Scene performance. Even with URPs built-in optimization settings, it’s ultimately up to you to make sure you aren’t overloading your project with lights and impeding performance.