Gabriel Borges

Results 3 issues of Gabriel Borges

![image](https://user-images.githubusercontent.com/51276652/71557858-c75d6080-2a2a-11ea-98d7-cbe417885682.png) When the camera turns, somes faces have this "negative specular". [Reddit post](https://www.reddit.com/r/godot/comments/eguugg/problems_on_psx_shaders/)

Added Rate (velocity) and Gain (volume) support.