[#746] Split refreshBackground() into 2D and 3D functions
[#746] Split refreshBackground() into 2D and 3D functions

baiyanghese/processing-js,guazipi/processing-js,jaredly/processing-js,jaredly/processing-js,jeresig/processing-js,jeresig/processing-js,corbanbrook/processing-js,guazipi/processing-js,corbanbrook/processing-js,kevinb7/processing-js,kevinb7/processing-js,baiyanghese/processing-js,corbanbrook/processing-js