Function fromZRotation

fromZRotation(out: mat4, rad: number): mat4
Creates a matrix from the given angle around the Z axis This is equivalent to (but much faster than):
```
mat4.identity(dest);
mat4.rotateZ(dest, dest, rad);
```
Parameters
- out: mat4
  mat4 receiving operation result
- rad: number
  the angle to rotate the matrix by
Returns mat4
out