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, 2 deletions

diff --git a/source/blender/draw/CMakeLists.txt b/source/blender/draw/CMakeLists.txt
index 0a62263ce3b..684134609c9 100644
--- a/source/blender/draw/CMakeLists.txt
+++ b/source/blender/draw/CMakeLists.txt
@@ -71,11 +71,9 @@ set(SRC
   intern/draw_attributes.cc
   intern/draw_cache_impl_curve.cc
   intern/draw_cache_impl_curves.cc
-  intern/draw_cache_impl_displist.c
   intern/draw_cache_impl_gpencil.c
   intern/draw_cache_impl_lattice.c
   intern/draw_cache_impl_mesh.cc
-  intern/draw_cache_impl_metaball.c
   intern/draw_cache_impl_particles.c
   intern/draw_cache_impl_pointcloud.cc
   intern/draw_cache_impl_subdivision.cc