Custom Actor Shader
When rendering most of the actors (characters and backgrounds, except generic ones) a special shader is used to handle semi-transparency overdraw and support various transition effects.
You can override the default shader by assigning a custom one to Custom Texture Shader
property available in the actor configuration menu.
Be aware, that the shader is expected to have specific properties; check default shader Naninovel/Resources/Naninovel/Shaders/TransitionalTexture
for a reference.
When actor is represented as a sprite on a scene, Custom Sprite Shader
property is available (the case for non-generic implementations when they're not rendered to texture). By default, a simple unlit transparent shader is used; in case you want to implement lighting or surface effects, assign a custom shader to the property.
EXAMPLE
Check the sample on GitHub for an example on how to create and use texture shader for adding custom transition effects and sprite shader with lighting and self-illumination support to simulate time of day for a background actor.