Changes

Turns on the next numerical layer in the background area specified by ''A''. For example, if background area 3 is currently set to [[FF7/Field/Script/Opcodes/E0 BGON|display layer ]] 1 for that particular area, a call to BGROL(0,3) will display layer 2 for that area. If an invalid layer is given, or the background rolls past the last layer for this area, no background is displayed by this opcode.