Tweaked opacity function to force more computation
Tweaked opacity function to force more computation

Change-Id: I2eebb5836ab63fef457afbd74f076080a16ca5aa

keithroe/vtkoptix,ashray/VTK-EVM,ashray/VTK-EVM,jmerkow/VTK,gram526/VTK,mspark93/VTK,ashray/VTK-EVM,sumedhasingla/VTK,demarle/VTK,sankhesh/VTK,sumedhasingla/VTK,msmolens/VTK,keithroe/vtkoptix,ashray/VTK-EVM,ashray/VTK-EVM,hendradarwin/VTK,mspark93/VTK,sankhesh/VTK,hendradarwin/VTK,ashray/VTK-EVM,hendradarwin/VTK,hendradarwin/VTK,candy7393/VTK,ashray/VTK-EVM,sumedhasingla/VTK,gram526/VTK,demarle/VTK,SimVascular/VTK,demarle/VTK,gram526/VTK,msmolens/VTK,sumedhasingla/VTK,sumedhasingla/VTK,demarle/VTK,SimVascular/VTK,hendradarwin/VTK,keithroe/vtkoptix,gram526/VTK,hendradarwin/VTK,sankhesh/VTK,candy7393/VTK,candy7393/VTK,keithroe/vtkoptix,SimVascular/VTK,mspark93/VTK,jmerkow/VTK,sankhesh/VTK,jmerkow/VTK,candy7393/VTK,demarle/VTK,sumedhasingla/VTK,SimVascular/VTK,jmerkow/VTK,sumedhasingla/VTK,mspark93/VTK,msmolens/VTK,hendradarwin/VTK,SimVascular/VTK,mspark93/VTK,candy7393/VTK,candy7393/VTK,candy7393/VTK,keithroe/vtkoptix,msmolens/VTK,SimVascular/VTK,sankhesh/VTK,sumedhasingla/VTK,jmerkow/VTK,mspark93/VTK,jmerkow/VTK,keithroe/vtkoptix,jmerkow/VTK,msmolens/VTK,gram526/VTK,mspark93/VTK,keithroe/vtkoptix,demarle/VTK,demarle/VTK,gram526/VTK,sankhesh/VTK,gram526/VTK,jmerkow/VTK,mspark93/VTK,gram526/VTK,sankhesh/VTK,sankhesh/VTK,SimVascular/VTK,msmolens/VTK,candy7393/VTK,SimVascular/VTK,keithroe/vtkoptix,demarle/VTK,msmolens/VTK,ashray/VTK-EVM,msmolens/VTK