Microsoft DirectX 8.0 (C++)

Bias

rn_bias

Shift each channel down by ½. So, it performs y = (x-0.5) before the register is operated on.

The following example shows how to use this modifier.

add r0, r0, t0_bias    ; Shift down by 0.5.

This example shows how to use add to perform the same operation as D3DTOP_ADDSIGNED in Microsoft® DirectX® 6.0 and 7.0 multitexture syntax.

This modifier has the effect of modifying data that was in the range 0 to 1 to be in the range -0.5 to 0.5. This is commonly used for applying detail textures. It can also enable the input data to be processed as a signed quantity while reserving dynamic range before overflow clamping that can occur on implementations limited to the range -1 to1.

Note that this modifier is mutually exclusive with Invert, so it cannot be applied to the same register.

This modifier is for use with the color and alpha blending instructions.