Swizzling (computer graphics)

Not to be confused with Pointer swizzling.

In computer graphics, swizzling is the ability to compose vectors by arbitrarily rearranging and combining components of other vectors. For example, if A = {1,2,3,4}, where the components are x, y, z, and w respectively, you could compute B = A.wwxy, whereupon B would equal {4,4,1,2}. Additionally, combining two two-component vectors can create a four-component vector, or any combination of vectors and swizzling. This is common in GPGPU applications.

In terms of linear algebra, this is equivalent to multiplying by a matrix whose rows are standard basis vectors. If $A=(1,2,3,4)^{T}$, then swizzling $A$ as above looks like

$A.wwxy={\begin{bmatrix}0&0&0&1\\0&0&0&1\\1&0&0&0\\0&1&0&0\end{bmatrix}}{\begin{bmatrix}1\\2\\3\\4\end{bmatrix}}={\begin{bmatrix}4\\4\\1\\2\end{bmatrix}}$

See also

• Z-order curve

External links

• OpenGL Vertex Program documentation