why DirectionalLight is not casting shadow?

问题

Code:

Color color = new Color(1f,1f,1f,0.9f);
DirectionalLight directionalLight = new DirectionalLight(rayHandler,200,color,-90f);
directionalLight.setSoftnessLength(0);

Result:

When light falls directly from above, why it is not casting shadows from boxes?

回答1:

This could be caused by a few things. Some things to check:

1. Check if your RayHandler is set to blur. Blurring with small objects can hide shadows.
2. Check the Shadows are enabled in the ray handler.
3. Check the ambient light is off or lower than the directional light. If ambient light is too high it may hide shadows.
4. Check your objects are larger than 0.1f as this is the smallest distance box2dlights works with
5. Check the light is not set to x-ray
6. check softness length. lights with high softness will have their light bleed through small objects.

来源：https://stackoverflow.com/questions/51858339/why-directionallight-is-not-casting-shadow