MetaBall support for Workbench + EEVEE

Note: Metaballs only support the first material slot. Splicing it per
material would create empty Batches. In order to overcome this we set
the batch for other materials to NULL. We added extra checks in EEVEE
and Workbench to not draw when the geom is NULL.

1 files changed, 28 insertions, 1 deletions

diff --git a/source/blender/draw/intern/draw_cache_impl_metaball.c b/source/blender/draw/intern/draw_cache_impl_metaball.c
index f01e7b929f8..24930921bee 100644
--- a/source/blender/draw/intern/draw_cache_impl_metaball.c
+++ b/source/blender/draw/intern/draw_cache_impl_metaball.c
@@ -49,7 +49,9 @@ static void metaball_batch_cache_clear(MetaBall *mb);
 
 typedef struct MetaBallBatchCache {
 	Gwn_Batch *batch;
+	Gwn_Batch **shaded_triangles;
 
+	int mat_len;
 	/* settings to determine if cache is invalid */
 	bool is_dirty;
 } MetaBallBatchCache;
@@ -75,6 +77,8 @@ static void metaball_batch_cache_init(MetaBall *mb)
 		cache = mb->batch_cache = MEM_mallocN(sizeof(*cache), __func__);
 	}
 	cache->batch = NULL;
+	cache->mat_len = 0;
+	cache->shaded_triangles = NULL;
 	cache->is_dirty = false;
 }
 
@@ -110,6 +114,9 @@ static void metaball_batch_cache_clear(MetaBall *mb)
 	}
 
 	GWN_BATCH_DISCARD_SAFE(cache->batch);
+	/* Note: shaded_triangles[0] is already freed by cache->batch */
+	MEM_SAFE_FREE(cache->shaded_triangles);
+	cache->mat_len = 0;
 }
 
 void DRW_mball_batch_cache_free(MetaBall *mb)
@@ -125,8 +132,9 @@ void DRW_mball_batch_cache_free(MetaBall *mb)
 
 Gwn_Batch *DRW_metaball_batch_cache_get_triangles_with_normals(Object *ob)
 {
-	if (!BKE_mball_is_basis(ob))
+	if (!BKE_mball_is_basis(ob)) {
 		return NULL;
+	}
 
 	MetaBall *mb = ob->data;
 	MetaBallBatchCache *cache = metaball_batch_cache_get(mb);
@@ -142,3 +150,22 @@ Gwn_Batch *DRW_metaball_batch_cache_get_triangles_with_normals(Object *ob)
 
 	return cache->batch;
 }
+
+Gwn_Batch **DRW_metaball_batch_cache_get_surface_shaded(Object *ob, MetaBall *mb, struct GPUMaterial **UNUSED(gpumat_array), uint gpumat_array_len)
+{
+	if (!BKE_mball_is_basis(ob)) {
+		return NULL;
+	}
+
+	MetaBallBatchCache *cache = metaball_batch_cache_get(mb);
+	if (cache->shaded_triangles == NULL) {
+		cache->mat_len = gpumat_array_len;
+		cache->shaded_triangles = MEM_callocN(sizeof(*cache->shaded_triangles) * cache->mat_len, __func__);
+		cache->shaded_triangles[0] = DRW_metaball_batch_cache_get_triangles_with_normals(ob);
+		for (int i = 1; i < cache->mat_len; ++i) {
+			cache->shaded_triangles[i] = NULL;
+		}
+	}
+	return cache->shaded_triangles;
+
+}