Sets the unsigned 8-bit (byte) bitflag mask that will be bitwise ANDed with all values as they are read (tested) from the Stencil Buffer

This can be considered a "niche" Stencil function as it is not required for many Stencil use-cases.

This is a companion function to render.SetStencilWriteMask which modifies Stencil Buffer values as they are written.

For more detailed information on the Stencil system, including usage examples, see the Stencils Render Reference page