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https://github.com/IfcOpenShell/IfcOpenShell.git
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76 lines
3.3 KiB
C++
76 lines
3.3 KiB
C++
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/********************************************************************************
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* *
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* This file is part of IfcOpenShell. *
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* *
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* IfcOpenShell is free software: you can redistribute it and/or modify *
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* it under the terms of the Lesser GNU General Public License as published by *
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* the Free Software Foundation, either version 3.0 of the License, or *
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* (at your option) any later version. *
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* *
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* IfcOpenShell is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* Lesser GNU General Public License for more details. *
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* *
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* You should have received a copy of the Lesser GNU General Public License *
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* along with this program. If not, see <http://www.gnu.org/licenses/>. *
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* *
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********************************************************************************/
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#ifndef BVHACCEL_H
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#define BVHACCEL_H
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#include <cstdint>
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#include <vector>
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#include <unordered_map>
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#include <unordered_set>
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#include <memory>
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struct ObjectDrawInfo {
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uint32_t index_offset; // byte offset into EBO
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uint32_t index_count; // number of indices
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uint32_t model_id; // which model this object belongs to
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float aabb_min[3]; // world-space AABB
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float aabb_max[3];
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};
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static constexpr uint32_t BVH_MAX_LEAF_SIZE = 8;
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static constexpr uint32_t BVH_MIN_OBJECTS = 32;
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struct BvhNode {
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float aabb_min[3];
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float aabb_max[3];
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uint32_t right_or_first; // interior: right child index (left is always this_index+1); leaf: first object index
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uint16_t count; // 0 = interior; >0 = leaf with this many objects
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uint16_t axis; // split axis (0/1/2) for interior; unused for leaf
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};
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static_assert(sizeof(BvhNode) == 32, "BvhNode must be 32 bytes for cache alignment and sidecar format");
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struct ModelBvh {
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uint32_t model_id = 0;
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std::vector<BvhNode> nodes;
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std::vector<uint32_t> object_indices; // indices into object_draw_info_
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};
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struct BvhSet {
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std::unordered_map<uint32_t, ModelBvh> models;
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std::unordered_set<uint32_t> bvh_model_ids;
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};
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struct EboReorderResult {
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std::vector<uint32_t> reordered_ebo;
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std::vector<ObjectDrawInfo> reordered_draw_info;
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};
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// Build BVH trees for all models in the given draw info snapshot.
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// Only builds the tree structure; does not touch EBO data.
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std::shared_ptr<BvhSet> buildBvhSet(const std::vector<ObjectDrawInfo>& draw_info);
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// Reorder the EBO so objects within each BVH leaf are contiguous.
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// Must be called with the CURRENT run's EBO and draw_info (not cached).
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EboReorderResult reorderEbo(const BvhSet& bvh_set,
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const std::vector<ObjectDrawInfo>& draw_info,
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const std::vector<uint32_t>& original_ebo);
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#endif // BVHACCEL_H
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