Metaball: Evaluate metaball objects as mesh components

With the ultimate goal of simplifying drawing and evaluation,
this patch makes the following changes and removes code:
- Use `Mesh` instead of `DispList` for evaluated basis metaballs.
- Remove all `DispList` drawing code, which is now unused.
- Simplify code that converts evaluated metaballs to meshes.
- Store the evaluated mesh in the evaluated geometry set.

This has the following indirect benefits:
- Evaluated meshes from metaball objects can be used in geometry nodes.
- Renderers can ignore evaluated metaball objects completely
- Cycles rendering no longer has to convert to mesh from `DispList`.
- We get closer to removing `DispList` completely.
- Optimizations to mesh rendering will also apply to metaball objects.

The vertex normals on the evaluated mesh are technically invalid;
the regular calculation wouldn't reproduce them. Metaball objects
don't support modifiers though, so it shouldn't be a problem.
Eventually we can support per-vertex custom normals (T93551).

Differential Revision: https://developer.blender.org/D14593

1 files changed, 0 insertions, 1 deletions

diff --git a/source/blender/blenkernel/BKE_lattice.h b/source/blender/blenkernel/BKE_lattice.h
index 9fa59c9e81b..aa4b1c69d24 100644
--- a/source/blender/blenkernel/BKE_lattice.h
+++ b/source/blender/blenkernel/BKE_lattice.h
@@ -27,7 +27,6 @@ void BKE_lattice_resize(struct Lattice *lt, int u, int v, int w, struct Object *
 struct Lattice *BKE_lattice_add(struct Main *bmain, const char *name);
 void calc_lat_fudu(int flag, int res, float *r_fu, float *r_du);
 
-bool object_deform_mball(struct Object *ob, struct ListBase *dispbase);
 void outside_lattice(struct Lattice *lt);
 
 float (*BKE_lattice_vert_coords_alloc(const struct Lattice *lt, int *r_vert_len))[3];