Fix lighting with custom material and shadows

There are two problems with the shadows.
1. The shader cache key for default materials is not properly initialized,
   which causes invalid shader being used for the material.
2. Custom material shadow cubes and maps uniforms are not set correctly.
   Only first element in those sampler arrays were set, so when custom material
   lighting had more then 1 light and shadows, only one light affected the
   rendered result.

Fixed the default material key and implemented proper setters for sampler
uniforms.

Task-number: QT3DS-1824
Change-Id: I0b97a4642410f37011392adf1020bc1d2bd21bb3
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Tomi Korpipää <tomi.korpipaa@qt.io>

0 files changed, 0 insertions, 0 deletions