BVH frustum culling, sidecar cache, per-model buffers, progressive upload

Phase 2 performance: BVH acceleration with median-split build, per-model trees, and EBO re-sorting for GPU cache coherence. Raw binary .ifcview sidecar stores full geometry + BVH for instant subsequent loads (skip tessellation entirely). Per-model GPU buffers (VAO/VBO/EBO per model) eliminate cross-model buffer copies on growth. Sidecar reads happen on a background thread. Bulk GPU uploads are progressive (48 MB/frame chunks) so the viewport stays interactive while multi-GB models stream in. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-09-09 13:52:23 +00:00 · 2026-04-12 09:09:32 +10:00
parent 5b4c1089cf
commit 1dace18d26
9 changed files with 1541 additions and 327 deletions
@@ -0,0 +1,76 @@
+/********************************************************************************
+ *                                                                              *
+ * This file is part of IfcOpenShell.                                           *
+ *                                                                              *
+ * IfcOpenShell is free software: you can redistribute it and/or modify         *
+ * it under the terms of the Lesser GNU General Public License as published by  *
+ * the Free Software Foundation, either version 3.0 of the License, or          *
+ * (at your option) any later version.                                          *
+ *                                                                              *
+ * IfcOpenShell 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                 *
+ * Lesser GNU General Public License for more details.                          *
+ *                                                                              *
+ * You should have received a copy of the Lesser GNU General Public License     *
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.         *
+ *                                                                              *
+ ********************************************************************************/
+
+#ifndef SIDECARCACHE_H
+#define SIDECARCACHE_H
+
+#include "BvhAccel.h"
+
+#include <cstdint>
+#include <optional>
+#include <string>
+#include <vector>
+
+static constexpr uint32_t SIDECAR_MAGIC   = 0x49465657;  // "IFVW"
+static constexpr uint32_t SIDECAR_VERSION = 3;
+static constexpr uint32_t SIDECAR_ENDIAN  = 0x01020304;
+
+// Fixed-size element record for the sidecar.  Strings are stored as
+// (offset, length) pairs into a separate string table.
+struct PackedElementInfo {
+    uint32_t object_id;
+    uint32_t model_id;
+    int32_t  ifc_id;
+    int32_t  parent_id;
+    uint32_t guid_offset;
+    uint32_t guid_length;
+    uint32_t name_offset;
+    uint32_t name_length;
+    uint32_t type_offset;
+    uint32_t type_length;
+};
+
+// Everything the viewer needs to display a model without tessellating.
+struct SidecarData {
+    // GPU geometry (ready to upload as-is)
+    std::vector<float>    vertices;      // interleaved, 8 floats per vertex
+    std::vector<uint32_t> indices;       // global (already remapped)
+
+    // Per-object metadata
+    std::vector<ObjectDrawInfo> draw_info;
+
+    // Element tree metadata
+    std::vector<PackedElementInfo> elements;
+    std::string string_table;            // concatenated UTF-8
+
+    // BVH acceleration
+    std::shared_ptr<BvhSet> bvh_set;
+};
+
+// Write a full sidecar next to the IFC file.
+// Returns true on success.
+bool writeSidecar(const std::string& ifc_path,
+                  const SidecarData& data,
+                  uint64_t ifc_file_size);
+
+// Read a sidecar.  Returns nullopt on any failure (missing, stale, corrupt).
+std::optional<SidecarData> readSidecar(const std::string& ifc_path,
+                                       uint64_t ifc_file_size);
+
+#endif // SIDECARCACHE_H