Update DepthOfField.cs FocalDistance approaching zero was causing a numeric issue and assert. Some DOF shader optims - Work in progress Some DOF optimisations including eliminating trig from pixel loop. This is Work in Progress, could do more optims here. Optimisations to Postprocessing shaders Optims to Postprocessing - Depth of Field, Bloom, Blur, Sharpen, Also DoF bug fix on focal distance at 0 Merge branch 'master' into MDV---PostProcessing-optims Post processing optims / tidyups Depth of field & blur - several mods - trig. eliminated in loops + other minor improvements. DoF bug fixed when focal distance close to 0 previously asserted. math fixed. Merge branch 'MDV---PostProcessing-optims'