Constant Boolean Register

This register is a collection of bits used in static flow control instructions (for example, if bool - vs - else - vs - endif - vs). There are 16 of them, therefore, a shader can have 16 independent branch conditions. They can be set using defb - vs or IDirect3DDevice9::SetVertexShaderConstantI.

The behavior of shader constants has changed between Direct3D 8 and Direct3D 9.