Add LTCLightManager#

In order to use LTC lights, there must exist one and only one LTCLightManager instance in scene. Create an empty game object, and add LTCLightManger component to it.

The PrefilterTexture shader is located in

Real Time Area Lights/Shaders/PrefilterTexture.shader. It is used for Textured Light, and should be assigned to LTCLightManager.

Or you can use the Prefabs/LTCManager.prefab directly without additional setup.

Shader Modification#

In the next step, minor shader modification is needed to make materials receiving LTC lighting with.

For Shader Graph#

There is no way for us to intercept the lighting process of fragment block, but we can connect our additional lighting to the emission channel, which will be added to the final lighting result.

So you need to create a LTCLighting node (inclued in this package) in shader graph, get input channels which is almost identical with fragment block, and link output to fragment block’s emission. Refer to the ShaderGraph sample.

For Shader Code#

It’s also convenient to extend your hand written shaders to receive LTC lighting, there already exists helper functions to convert URP’s lit shader input to LTC lighting input, actually they are quite the same.

Use URP lit as an example, firstly we should include LTC shaders in LitForwardPass.hlsl:

#include "Packages/com.petabytes.ltclight/Shaders/LTC_URP.hlsl"

Then add LTC lighting after URP’s PBR calculation:

// For example in LitForwardPass.hlsl
InitializeBakedGIData(input, inputData);
half4 color = UniversalFragmentPBR(inputData, surfaceData);

// Add LTC lighting here
color.rgb += CalculateFragmentLTC(inputData, surfaceData);

Refer to the shader code sample.

Add LTC Light Components#

The last step is adding LTC light instances in your scene.

You can create an empty GameObject, and add LTC components to it, there three types of lights can be used directly:

LTC Linear Light

LTC Polygon Light

LTC Textured Light:

LTC Light is the base class of above three light types, it can’t be used directly.

Or use the light prefabs in Real Time Area Lights/Prefabs directory: