remove m_random_gp
fix #1395
Use a default texture for rubber band
Some shader factorization
Fix shadows.
Fix RSM
Factorize splatting material.
Avoid drawing negative color with splatting material.
Try to factorize shader using variadic templates.
Turn Pass 1 shader to singleton, and factorize the setUniforms.
Try to fix linux compilation.
try to fix shader.hpp.
Try another (dirty) fix.
Add userconfig param
Factorize some pass2 shaders init code
Factorize detail and spheremap
Fix linux build.
Factorize unlit shader.
Factorize transparent shaders.
Factorize splatting shader.