1 files changed, 93 insertions, 0 deletions
diff --git a/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_skin_roots.cc b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_skin_roots.cc
new file mode 100644
index 00000000000..d7a01ee607f
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+++ b/source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_skin_roots.cc
@@ -0,0 +1,93 @@
+/*
+ * 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) 2021 by Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup draw
+ */
+
+#include "draw_cache_extract_mesh_private.h"
+
+namespace blender::draw {
+
+/* ---------------------------------------------------------------------- */
+/** \name Extract Skin Modifier Roots
+ * \{ */
+
+struct SkinRootData {
+  float size;
+  float local_pos[3];
+};
+
+static void extract_skin_roots_init(const MeshRenderData *mr,
+                                    struct MeshBatchCache *UNUSED(cache),
+                                    void *buf,
+                                    void *UNUSED(tls_data))
+{
+  GPUVertBuf *vbo = static_cast<GPUVertBuf *>(buf);
+  /* Exclusively for edit mode. */
+  BLI_assert(mr->bm);
+
+  static GPUVertFormat format = {0};
+  if (format.attr_len == 0) {
+    GPU_vertformat_attr_add(&format, "size", GPU_COMP_F32, 1, GPU_FETCH_FLOAT);
+    GPU_vertformat_attr_add(&format, "local_pos", GPU_COMP_F32, 3, GPU_FETCH_FLOAT);
+  }
+
+  GPU_vertbuf_init_with_format(vbo, &format);
+  GPU_vertbuf_data_alloc(vbo, mr->bm->totvert);
+
+  SkinRootData *vbo_data = (SkinRootData *)GPU_vertbuf_get_data(vbo);
+
+  int root_len = 0;
+  int cd_ofs = CustomData_get_offset(&mr->bm->vdata, CD_MVERT_SKIN);
+
+  BMIter iter;
+  BMVert *eve;
+  BM_ITER_MESH (eve, &iter, mr->bm, BM_VERTS_OF_MESH) {
+    const MVertSkin *vs = (const MVertSkin *)BM_ELEM_CD_GET_VOID_P(eve, cd_ofs);
+    if (vs->flag & MVERT_SKIN_ROOT) {
+      vbo_data->size = (vs->radius[0] + vs->radius[1]) * 0.5f;
+      copy_v3_v3(vbo_data->local_pos, bm_vert_co_get(mr, eve));
+      vbo_data++;
+      root_len++;
+    }
+  }
+
+  /* It's really unlikely that all verts will be roots. Resize to avoid losing VRAM. */
+  GPU_vertbuf_data_len_set(vbo, root_len);
+}
+
+constexpr MeshExtract create_extractor_skin_roots()
+{
+  MeshExtract extractor = {nullptr};
+  extractor.init = extract_skin_roots_init;
+  extractor.data_type = MR_DATA_NONE;
+  extractor.data_size = 0;
+  extractor.use_threading = false;
+  extractor.mesh_buffer_offset = offsetof(MeshBufferCache, vbo.skin_roots);
+  return extractor;
+}
+
+/** \} */
+
+}  // namespace blender::draw
+
+extern "C" {
+const MeshExtract extract_skin_roots = blender::draw::create_extractor_skin_roots();
+}