Subdiv: Some ground work for CCG support

Nothing really interesting, just starting laying down API which
seems to be a decent substitute to CCGDM, without requiring too
much work be done in sculpting area.

1 files changed, 127 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/subdiv_ccg.c b/source/blender/blenkernel/intern/subdiv_ccg.c
new file mode 100644
index 00000000000..647869dca7e
--- /dev/null
+++ b/source/blender/blenkernel/intern/subdiv_ccg.c
@@ -0,0 +1,127 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2018 by Blender Foundation.
+ * All rights reserved.
+ *
+ * Contributor(s): Sergey Sharybin.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/blenkernel/intern/subdiv_ccg.c
+ *  \ingroup bke
+ */
+
+#include "BKE_subdiv_ccg.h"
+
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "BKE_ccg.h"
+#include "BKE_subdiv.h"
+
+static void subdiv_ccg_init_layers(SubdivCCG *subdiv_ccg,
+                                   const SubdivToCCGSettings *settings)
+{
+	/* CCG always contains coordinates. Rest of layers are coming after them. */
+	int layer_offset = sizeof(float) * 3;
+	/* Normals. */
+	if (settings->need_normal) {
+		subdiv_ccg->has_normal = true;
+		subdiv_ccg->normal_offset = layer_offset;
+		layer_offset += sizeof(float) * 3;
+	}
+	else {
+		subdiv_ccg->has_normal = false;
+		subdiv_ccg->normal_offset = -1;
+	}
+	/* Mask. */
+	if (settings->need_mask) {
+		subdiv_ccg->has_mask = true;
+		subdiv_ccg->mask_offset = layer_offset;
+		layer_offset += sizeof(float);
+	}
+	else {
+		subdiv_ccg->has_mask = false;
+		subdiv_ccg->mask_offset = -1;
+	}
+}
+
+static int grid_size_for_level_get(const SubdivCCG *subdiv_ccg, int level)
+{
+	BLI_assert(level >= 1);
+	BLI_assert(level <= subdiv_ccg->level);
+	return (1 << (level - 1)) + 1;
+}
+
+/* Per-vertex element size in bytes. */
+static int element_size_get(const SubdivCCG *subdiv_ccg)
+{
+	/* We always have 3 floats for coordinate. */
+	int num_floats = 3;
+	if (subdiv_ccg->has_normal) {
+		num_floats += 3;
+	}
+	if (subdiv_ccg->has_mask) {
+		num_floats += 1;
+	}
+	return sizeof(float) * num_floats;
+}
+
+SubdivCCG *BKE_subdiv_to_ccg(
+        Subdiv *UNUSED(subdiv),
+        const SubdivToCCGSettings *settings,
+        const Mesh *UNUSED(coarse_mesh))
+{
+	SubdivCCG *subdiv_ccg = MEM_callocN(sizeof(SubdivCCG *), "subdiv ccg");
+	subdiv_ccg->level = settings->resolution >> 1;
+	subdiv_ccg->grid_size =
+	        grid_size_for_level_get(subdiv_ccg, subdiv_ccg->level);
+	subdiv_ccg_init_layers(subdiv_ccg, settings);
+	return NULL;
+}
+
+void BKE_subdiv_ccg_destroy(SubdivCCG *subdiv_ccg)
+{
+	MEM_SAFE_FREE(subdiv_ccg->grids);
+	MEM_SAFE_FREE(subdiv_ccg->edges);
+	MEM_SAFE_FREE(subdiv_ccg->vertices);
+	MEM_freeN(subdiv_ccg);
+}
+
+void BKE_subdiv_ccg_key(CCGKey *key, const SubdivCCG *subdiv_ccg, int level)
+{
+	key->level = level;
+	key->elem_size = element_size_get(subdiv_ccg);
+	key->grid_size = grid_size_for_level_get(subdiv_ccg, level);
+	key->grid_area = key->grid_size * key->grid_size;
+	key->grid_bytes = key->elem_size * key->grid_area;
+
+	key->normal_offset = subdiv_ccg->normal_offset;
+	key->mask_offset = subdiv_ccg->mask_offset;
+
+	key->has_normals = subdiv_ccg->has_normal;
+	key->has_mask = subdiv_ccg->has_mask;
+}
+
+void BKE_subdiv_ccg_key_top_level(CCGKey *key, const SubdivCCG *subdiv_ccg)
+{
+	BKE_subdiv_ccg_key(key, subdiv_ccg, subdiv_ccg->level);
+}