Add MeshAccelerationStructure utility for robust triangles geometry queries

2022-02-27 13:29:58 +01:00
parent 3fe1e2c763
commit 8271a2b718
2 changed files with 597 additions and 0 deletions
--- a/Source/Engine/Tools/ModelTool/MeshAccelerationStructure.h
+++ b/Source/Engine/Tools/ModelTool/MeshAccelerationStructure.h
@@ -0,0 +1,75 @@
+// Copyright (c) 2012-2022 Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if COMPILE_WITH_MODEL_TOOL
+
+#include "Engine/Core/Math/Triangle.h"
+#include "Engine/Core/Math/BoundingBox.h"
+#include "Engine/Core/Types/DataContainer.h"
+#include "Engine/Core/Collections/Array.h"
+
+class Model;
+
+/// <summary>
+/// Acceleration Structure utility for robust ray tracing mesh geometry with optimized data structure.
+/// </summary>
+class FLAXENGINE_API MeshAccelerationStructure
+{
+private:
+    struct Mesh
+    {
+        BytesContainer IndexBuffer, VertexBuffer;
+        int32 Indices, Vertices;
+        bool Use16BitIndexBuffer;
+        BoundingBox Bounds;
+    };
+
+    struct BVH
+    {
+        BoundingBox Bounds;
+
+        union
+        {
+            struct
+            {
+                uint32 IsLeaf : 1;
+                uint16 TriangleCount : 15;
+                uint16 MeshIndex : 16;
+                uint32 TriangleIndex;
+            } Leaf;
+
+            struct
+            {
+                uint32 IsLeaf : 1;
+                uint32 ChildrenCount : 31;
+                int32 ChildIndex;
+            } Node;
+        };
+    };
+
+    Array<Mesh, InlinedAllocation<16>> _meshes;
+    Array<BVH> _bvh;
+
+    void BuildBVH(int32 node, int32 maxLeafSize, Array<byte>& scratch);
+    bool PointQueryBVH(int32 node, const Vector3& point, float& hitDistance, Vector3& hitPoint, Triangle& hitTriangle) const;
+    bool RayCastBVH(int32 node, const Ray& ray, float& hitDistance, Vector3& hitNormal, Triangle& hitTriangle) const;
+
+public:
+    // Adds the model geometry for the build to the structure.
+    void Add(Model* model, int32 lodIndex);
+
+    // Adds the triangles geometry for the build to the structure.
+    void Add(Vector3* vb, int32 vertices, void* ib, int32 indices, bool use16BitIndex, bool copy = false);
+
+    // Builds Bounding Volume Hierarchy (BVH) structure for accelerated geometry queries.
+    void BuildBVH(int32 maxLeafSize = 16);
+
+    // Queries the closest triangle.
+    bool PointQuery(const Vector3& point, float& hitDistance, Vector3& hitPoint, Triangle& hitTriangle, float maxDistance = MAX_float) const;
+
+    // Ray traces the triangles.
+    bool RayCast(const Ray& ray, float& hitDistance, Vector3& hitNormal, Triangle& hitTriangle, float maxDistance = MAX_float) const;
+};
+
+#endif