dcl_usage - ps

Declare the association between vertex shader output and pixel shader input.

Syntax

Where:

• _semantics: Identifies the intended data usage, and may be any of the values in D3DDECLUSAGE (without the D3DDECLUSAGE_ prefix). Additionally, an integer index can be appended to the semantic to distinguish parameters that use similar semantics.
• [_Centroid] is an optional instruction modifier. It is is supported on dcl_usage instructions that declare the input registers and on texture lookup instructions. The centroid is appended with no space.
• dst: destination register. See ps_3_0 Registers.
• write_mask: The same output register may be declared multiple times, each time with a unique write mask (so different semantics can be applied to individual components). However, the same semantic cannot be used multiple times in a declaration. This means that vectors must be four components or less, and cannot go across four-component register boundaries (individual output registers). When the _psize semantic is used, it should have a full write mask because it is considered a scalar. When the _position semantic is used, it should have full write mask because all four components have to be written.

Remarks

All dcl_usage instructions must appear before the first executable instruction.

Declaration Examples

ps_3_0

; Declaring inputs
dcl_normal      v0.xyz
dcl_blendweight v0.w ; Must be same reg# as normal, matching vshader packing
dcl_texcoord1   v1.y ; Mask can be any subset of mask from vshader semantic
dcl_texcoord0   v1.zw; Has to be same reg# as texcoord1, to match vshader

; Declaring samplers
dcl_2d s0
dcl_2d s1

def c0, 0, 0, 0, 0

mov r0.x, v1.y ; texcoord1
mov r0.y, c0
texld r0, r0, s0

texld r1, v1.zw, s1
...
(output regs in ps_3_0 are same as ps_2_0: oC0-oC3, oDepth)

See Also

Antialias Sample