Engine directory for ticket #1

Engine/source/util/quadTreeTracer.h

@@ -0,0 +1,104 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) 2012 GarageGames, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//-----------------------------------------------------------------------------
+
+#ifndef _QUADTREETRACER_H_
+#define _QUADTREETRACER_H_
+
+#include "platform/platform.h"
+#include "math/mPoint3.h"
+#include "scene/sceneObject.h"
+
+/// Helper class to perform a fast, recursive ray cast against a set of
+/// hierarchical bounding boxes.
+///
+/// This class assumes that it is working on a unit quadtree (ie, one that
+/// extends from 0..1 in the XY dimensions. Z scale is unaffected).
+///
+/// Node indexing is done TGE Terrain style - 0 is the largest level of the
+/// quadtree, while coordinates are always in the full range of the quadtree
+/// (in a 6 deep tree, 0..63, for instance). This allows the quadtree descent
+/// to be very fast!
+class QuadTreeTracer
+{
+protected:
+
+   struct StackNode
+   {
+      Point2I squarePos;
+      U32     level;
+   };
+
+   struct RayStackNode : StackNode
+   {
+      F32     startT;
+      F32     endT;
+   };
+
+   U32 mTreeDepth;
+
+   QuadTreeTracer(U32 treeDepth)
+      : mTreeDepth(treeDepth)
+   {
+   }
+
+   /// Children better implement these! They return min/max height bounds
+   /// of the specified square.
+   virtual const F32 getSquareMin(const U32 &level, const Point2I &pos) const = 0;
+   virtual const F32 getSquareMax(const U32 &level, const Point2I &pos) const = 0;
+
+   /// And this does checks on leaf nodes.
+   virtual bool castLeafRay(const Point2I pos, const Point3F &start, const Point3F &end, const F32 &startT, const F32 &endT, RayInfo *info) = 0;
+
+   /// Helper function to calculate intercepts.
+   inline const F32 calcIntercept(const F32 vStart, const F32 invDeltaV, const F32 intercept) const
+   {
+      return (intercept - vStart) * invDeltaV;
+   }
+
+public:
+
+   /// Size of a quadtree of depth.
+   static inline const U32 getNodeCount(const U32 depth)
+   {
+      return 0x55555555 & ((1 << depth*2) - 1);
+   }
+
+   /// Index of a node at given position in a quadtree.
+   static inline const U32 getNodeIndex(const U32 level, const Point2I pos)
+   {
+      //AssertFatal(level < mTreeDepth, "QuadTreeTracer::getNodeIndex - out of range level!)
+      AssertFatal(pos.x < BIT(level) && pos.x >= 0 , "QuadTreeTracer::getNodeIndex - out of range x for level!");
+      AssertFatal(pos.y < BIT(level) && pos.y >= 0 , "QuadTreeTracer::getNodeIndex - out of range y for level!");
+
+      const U32 base = getNodeCount(level);
+      return base + (pos.x << level) + pos.y;
+   }
+
+   /// Cast a ray against a quadtree of hierarchical bounding boxes.
+   ///
+   /// This method assumes the quadtree extends from (0..1) along the
+   /// X and Y axes. Z is unscaled. You may need to adjust the points
+   /// you pass into this method to get the proper results.
+   bool castRay(const Point3F &start, const Point3F &end, RayInfo *info);
+};
+
+#endif