When there are 2+ consecutive deform modifiers, the second modifier was getting incorrect normals, this only showed up for the displace modifier since its the only deform modifier that uses vertex normals.
It would have been easy to fix this by always calculating normals on deform modifiers, but slow.
To fix this I added a function to check if a deform modifier needs normals, so the normal calculation function only runs if there are 2 modifiers in a row and the second uses normals.
[#22310] Duplicate Does Not Propogate SimpleDeform's VGroup
[#22321] duplicating object with smoke settings doesnt duplicate smoke settings
^ Genscher, you may want to check that but I thought it was pretty straightforward.
patch by Ben Batt (artificer)
Updated patch for 6 or so modifiers added since the patch was written.
- tested with CMake and SCons
- fixed one error were flags were being added to the fluids type.
- remove BKE_simple_deform.h, simple_deform.c, move functions into MOD_simpledeform.c since there were problems with circular deps.
- moved some fluid and boolean functions used by modifiers too.
