dcl_semantics (sm3 - ps asm)
Declare the association between vertex shader output and pixel shader input.
Syntax
dcl_semantics [_centroid] dst[.write_mask]
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 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
| Pixel shader versions | 1_1 | 1_2 | 1_3 | 1_4 | 2_0 | 2_x | 2_sw | 3_0 | 3_sw |
|---|---|---|---|---|---|---|---|---|---|
| dcl_usage | x | x |
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)
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