Sets the transformation to be used for the the drawing operations on the
target bitmap (each bitmap maintains its own transformation).
Every drawing operation after this call will be transformed using this
Call this function with an identity transformation to return to the
This function does nothing if there is no target bitmap.
The parameter is passed by reference as an optimization to avoid the
overhead of stack copying.
The reference will not be stored in the Allegro library so it is safe to
pass references to local variables.
al_translate_transform(&transform, 5, 10);
trans - Transformation to use