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.

4 files changed, 41 insertions, 1 deletions

diff --git a/source/blender/draw/intern/draw_cache.c b/source/blender/draw/intern/draw_cache.c
index 14addfe9bcb..36a98d6cec3 100644
--- a/source/blender/draw/intern/draw_cache.c
+++ b/source/blender/draw/intern/draw_cache.c
@@ -26,6 +26,7 @@
 
 #include "DNA_scene_types.h"
 #include "DNA_mesh_types.h"
+#include "DNA_meta_types.h"
 #include "DNA_curve_types.h"
 #include "DNA_object_types.h"
 #include "DNA_particle_types.h"
@@ -576,6 +577,8 @@ Gwn_Batch **DRW_cache_object_surface_material_get(
 			return DRW_cache_surf_surface_shaded_get(ob, gpumat_array, gpumat_array_len);
 		case OB_FONT:
 			return DRW_cache_text_surface_shaded_get(ob, gpumat_array, gpumat_array_len);
+		case OB_MBALL:
+			return DRW_cache_mball_surface_shaded_get(ob, gpumat_array, gpumat_array_len);
 		default:
 			return NULL;
 	}
@@ -2804,6 +2807,14 @@ Gwn_Batch *DRW_cache_mball_surface_get(Object *ob)
 	return DRW_metaball_batch_cache_get_triangles_with_normals(ob);
 }
 
+Gwn_Batch **DRW_cache_mball_surface_shaded_get(
+        Object *ob, struct GPUMaterial **gpumat_array, uint gpumat_array_len)
+{
+	BLI_assert(ob->type == OB_MBALL);
+	MetaBall *mb = ob->data;
+	return DRW_metaball_batch_cache_get_surface_shaded(ob, mb, gpumat_array, gpumat_array_len);
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
diff --git a/source/blender/draw/intern/draw_cache.h b/source/blender/draw/intern/draw_cache.h
index 7a1c14b5076..871da9203ca 100644
--- a/source/blender/draw/intern/draw_cache.h
+++ b/source/blender/draw/intern/draw_cache.h
@@ -187,5 +187,6 @@ struct Gwn_Batch *DRW_cache_particles_get_prim(int type);
 
 /* Metaball */
 struct Gwn_Batch *DRW_cache_mball_surface_get(struct Object *ob);
+struct Gwn_Batch **DRW_cache_mball_surface_shaded_get(struct Object *ob, struct GPUMaterial **gpumat_array, uint gpumat_array_len);
 
 #endif /* __DRAW_CACHE_H__ */
diff --git a/source/blender/draw/intern/draw_cache_impl.h b/source/blender/draw/intern/draw_cache_impl.h
index 0f990c72d01..5773daf8e96 100644
--- a/source/blender/draw/intern/draw_cache_impl.h
+++ b/source/blender/draw/intern/draw_cache_impl.h
@@ -73,6 +73,7 @@ struct Gwn_Batch **DRW_curve_batch_cache_get_surface_shaded(
 
 /* Metaball */
 struct Gwn_Batch *DRW_metaball_batch_cache_get_triangles_with_normals(struct Object *ob);
+struct Gwn_Batch **DRW_metaball_batch_cache_get_surface_shaded(struct Object *ob, struct MetaBall *mb, struct GPUMaterial **gpumat_array, uint gpumat_array_len);
 
 /* Curve (Font) */
 struct Gwn_Batch *DRW_curve_batch_cache_get_overlay_cursor(struct Curve *cu);
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;
+
+}