Changeset 2430 for code/branches/physics/src/bullet/BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h

Timestamp:

Dec 13, 2008, 11:45:51 PM (16 years ago)

Author:

rgrieder

Message:

Updated to Bullet 2.73 (first part).

File:

• code/branches/physics/src/bullet/BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h (modified) (3 diffs)

code/branches/physics/src/bullet/BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h

@@ -19 +19 @@
 #include "btConcaveShape.h"
 
-///The btHeightfieldTerrainShape simulates a 2D heightfield terrain collision shape. You can also use the more general btBvhTriangleMeshShape instead.
-///An example implementation of btHeightfieldTerrainShape is provided in Demos/VehicleDemo/VehicleDemo.cpp
+///btHeightfieldTerrainShape simulates a 2D heightfield terrain
+/**
+  The caller is responsible for maintaining the heightfield array; this
+  class does not make a copy.
+
+  The heightfield can be dynamic so long as the min/max height values
+  capture the extremes (heights must always be in that range).
+
+  The local origin of the heightfield is assumed to be the exact
+  center (as determined by width and length and height, with each
+  axis multiplied by the localScaling).
+
+  Most (but not all) rendering and heightfield libraries assume upAxis = 1
+  (that is, the y-axis is "up").  This class allows any of the 3 coordinates
+  to be "up".  Make sure your choice of axis is consistent with your rendering
+  system.
+
+  The heightfield heights are determined from the data type used for the
+  heightfieldData array.  
+
+   - PHY_UCHAR: height at a point is the uchar value at the
+       grid point, multipled by heightScale.  uchar isn't recommended
+       because of its inability to deal with negative values, and
+       low resolution (8-bit).
+
+   - PHY_SHORT: height at a point is the short int value at that grid
+       point, multipled by heightScale.
+
+   - PHY_FLOAT: height at a point is the float value at that grid
+       point.  heightScale is ignored when using the float heightfield
+       data type.
+
+  Whatever the caller specifies as minHeight and maxHeight will be honored.
+  The class will not inspect the heightfield to discover the actual minimum
+  or maximum heights.  These values are used to determine the heightfield's
+  axis-aligned bounding box, multiplied by localScaling.
+
+  For usage and testing see the TerrainDemo.
+ */
 class btHeightfieldTerrainShape : public btConcaveShape
 {
@@ -26 +63 @@
         btVector3       m_localAabbMin;
         btVector3       m_localAabbMax;
-        
+        btVector3       m_localOrigin;
+
         ///terrain data
         int     m_heightStickWidth;
         int m_heightStickLength;
+        btScalar        m_minHeight;
         btScalar        m_maxHeight;
         btScalar m_width;
         btScalar m_length;
+        btScalar m_heightScale;
         union
         {
                 unsigned char*  m_heightfieldDataUnsignedChar;
+                short*          m_heightfieldDataShort;
                 btScalar*                       m_heightfieldDataFloat;
                 void*                   m_heightfieldDataUnknown;
         };
-        
-        bool    m_useFloatData;
+
+        PHY_ScalarType  m_heightDataType;       
         bool    m_flipQuadEdges;
   bool  m_useDiamondSubdivision;
@@ -52 +93 @@
         void            getVertex(int x,int y,btVector3& vertex) const;
 
-        inline bool testQuantizedAabbAgainstQuantizedAabb(int* aabbMin1, int* aabbMax1,const  int* aabbMin2,const  int* aabbMax2) const
-        {
-                bool overlap = true;
-                overlap = (aabbMin1[0] > aabbMax2[0] || aabbMax1[0] < aabbMin2[0]) ? false : overlap;
-                overlap = (aabbMin1[2] > aabbMax2[2] || aabbMax1[2] < aabbMin2[2]) ? false : overlap;
-                overlap = (aabbMin1[1] > aabbMax2[1] || aabbMax1[1] < aabbMin2[1]) ? false : overlap;
-                return overlap;
-        }
+
+
+        /// protected initialization
+        /**
+          Handles the work of constructors so that public constructors can be
+          backwards-compatible without a lot of copy/paste.
+         */
+        void initialize(int heightStickWidth, int heightStickLength,
+                        void* heightfieldData, btScalar heightScale,
+                        btScalar minHeight, btScalar maxHeight, int upAxis,
+                        PHY_ScalarType heightDataType, bool flipQuadEdges);
 
 public:
-        btHeightfieldTerrainShape(int heightStickWidth,int heightStickHeight,void* heightfieldData, btScalar maxHeight,int upAxis,bool useFloatData,bool flipQuadEdges);
+        /// preferred constructor
+        /**
+          This constructor supports a range of heightfield
+          data types, and allows for a non-zero minimum height value.
+          heightScale is needed for any integer-based heightfield data types.
+         */
+        btHeightfieldTerrainShape(int heightStickWidth,int heightStickLength,
+                                  void* heightfieldData, btScalar heightScale,
+                                  btScalar minHeight, btScalar maxHeight,
+                                  int upAxis, PHY_ScalarType heightDataType,
+                                  bool flipQuadEdges);
+
+        /// legacy constructor
+        /**
+          The legacy constructor assumes the heightfield has a minimum height
+          of zero.  Only unsigned char or floats are supported.  For legacy
+          compatibility reasons, heightScale is calculated as maxHeight / 65535 
+          (and is only used when useFloatData = false).
+         */
+        btHeightfieldTerrainShape(int heightStickWidth,int heightStickLength,void* heightfieldData, btScalar maxHeight,int upAxis,bool useFloatData,bool flipQuadEdges);
 
         virtual ~btHeightfieldTerrainShape();