Swizzling (Pixel Shader)

Swizzling refers to the ability to copy any source register component to any temporary register component. Swizzling does not affect the source register data. Before an instruction runs, the data in a source register is copied to a temporary register.

Source Swizzling

Source swizzle allows individual component of a source register to take on the value of any of the four components of the same source register before the register is read for computation.

For example, the .zxxy swizzle means:

.x component will take on the value of .z component
.y component will take on the value of .x component
.z component will take on the value of .x component
.w component will take on the value of .y component

The components can appear in any order. If fewer than four components are specified, the last component is repeated. For example:

.xy  = .xyyy
.wzx = .wzxx
.z   = .zzzz

If no component is specified, no swizzling is applied.

Some instructions have restrictions for source swizzle. They are listed in the respected instruction reference pages.

Pixel shader versions	1_1	1_2	1_3	1_4	2_0	2_x	2_sw	3_0	3_sw
swizzling	x	x	x	x	x	x	x	x	x

Arbitrary Swizzle

Swizzles can be applied to source registers in an arbitrary order; that is, any source register can take any component mask, in any order.

Pixel shader versions	1_1	1_2	1_3	1_4	2_0	2_sw	2_x	3_0	3_sw
arbitrary swizzling						x	x	x	x

Replicate Swizzle

Replicate swizzle, is used to replicate or copy one component to another. This is, exactly one of the .x, .y, .z, .w swizzle components (or the .r, .g, .b, .a equivalents) must be specified.