//=============================================================================
  // d3dUtil.h by Frank Luna (C) 2005 All Rights Reserved.
  //
  // Contains various utility code for DirectX applications, such as, clean up
  // and debugging code.
  //=============================================================================
  
  ifndef D3DUTIL_H
  define D3DUTIL_H
  
  // Enable extra D3D debugging in debug builds if using the debug DirectX runtime.  
  // This makes D3D objects work well in the debugger watch window, but slows down 
  // performance slightly.
  if defined(DEBUG) | defined(_DEBUG)
  ifndef D3D_DEBUG_INFO
  define D3D_DEBUG_INFO
  endif
  endif
  
  include <d3d9.h>
  include <d3dx9.h>
  include <dxerr9.h>
  include <string>
  include <sstream>
  include <vector>
  
  //===============================================================
  // Globals for convenient access.
  class D3DApp;
  extern D3DApp* gd3dApp;
  extern IDirect3DDevice9* gd3dDevice;
  
  //===============================================================
  // Clean up
  
  define ReleaseCOM(x) { if(x){ x->Release();x = 0; } }
  
  //===============================================================
  // Geometry generation.
  
  void GenTriGrid(int numVertRows, int numVertCols, 
          float dx, float dz, const D3DXVECTOR3& center, 
          std::vector<D3DXVECTOR3>& verts, std::vector<DWORD>& indices);
  
  //===============================================================
  // Colors and Materials
  
  const D3DXCOLOR WHITE(1.0f, 1.0f, 1.0f, 1.0f);
  const D3DXCOLOR BLACK(0.0f, 0.0f, 0.0f, 1.0f);
  const D3DXCOLOR RED(1.0f, 0.0f, 0.0f, 1.0f);
  const D3DXCOLOR GREEN(0.0f, 1.0f, 0.0f, 1.0f);
  const D3DXCOLOR BLUE(0.0f, 0.0f, 1.0f, 1.0f);
  
  struct Mtrl
  {
          Mtrl()
                  :ambient(WHITE), diffuse(WHITE), spec(WHITE), specPower(8.0f){}
          Mtrl(const D3DXCOLOR& a, const D3DXCOLOR& d, 
                   const D3DXCOLOR& s, float power)
                  :ambient(a), diffuse(d), spec(s), specPower(power){}
  
          D3DXCOLOR ambient;
          D3DXCOLOR diffuse;
          D3DXCOLOR spec;
          float specPower;
  };
  
  struct DirLight
  {
          D3DXCOLOR ambient;
          D3DXCOLOR diffuse;
          D3DXCOLOR spec;
          D3DXVECTOR3 dirW;
  };
  
  //===============================================================
  // .X Files
  
  void LoadXFile(
          const std::string& filename, 
          ID3DXMesh** meshOut, 
          std::vector<Mtrl>& mtrls, 
          std::vector<IDirect3DTexture9*>& texs);
  
  //===============================================================
  // Math Constants
  
  const float INFINITY = FLT_MAX;
  const float EPSILON  = 0.001f;
  
  //===============================================================
  // Bounding Volumes
  
  struct AABB 
  {
          // Initialize to an infinitely small bounding box.
          AABB()
                  : minPt(INFINITY, INFINITY, INFINITY),
                    maxPt(-INFINITY, -INFINITY, -INFINITY){}
  
      D3DXVECTOR3 center()
          {
                  return 0.5f*(minPt+maxPt);
          }
  
          D3DXVECTOR3 minPt;
          D3DXVECTOR3 maxPt;
  };
  
  struct BoundingSphere 
  {
          BoundingSphere()
                  : pos(0.0f, 0.0f, 0.0f), radius(0.0f){}
  
          D3DXVECTOR3 pos;
          float radius;
  };
  
  //===============================================================
  // Debug
  
  if defined(DEBUG) | defined(_DEBUG)
          #ifndef HR
          #define HR(x)                                      \
          {                                                  \
                  HRESULT hr = x;                                \
                  if(FAILED(hr))                                 \
                  {                                              \
                          DXTrace(__FILE__, __LINE__, hr, #x, TRUE); \
                  }                                              \
          }
          #endif
  
  else
          #ifndef HR
          #define HR(x) x;
          #endif
  endif 
  
  endif // D3DUTIL_H