//=============================================================================
  // XFileDemo.cpp by Frank Luna (C) 2005 All Rights Reserved.
  //
  // Demonstrates how to load and render the geometry stored in a .X file.
  //
  // Controls: Use mouse to orbit and zoom; use the 'W' and 'S' keys to 
  //           alter the height of the camera.
  //=============================================================================
  
  include <d3dApp.h>
  include <DirectInput.h>
  include <crtdbg.h>
  include <GfxStats.h>
  include <list>
  include <Vertex.h>
  
  class XFileDemo : public D3DApp
  {
  public:
          XFileDemo(HINSTANCE hInstance, std::string winCaption, D3DDEVTYPE devType, DWORD requestedVP);
          ~XFileDemo();
  
          bool checkDeviceCaps();
          void onLostDevice();
          void onResetDevice();
          void updateScene(float dt);
          void drawScene();
  
          // Helper methods
          void buildFX();
          void buildViewMtx();
          void buildProjMtx();
  
  private:
          GfxStats* mGfxStats;
          
          ID3DXMesh* mMesh;
          std::vector<Mtrl> mMtrl;
          std::vector<IDirect3DTexture9*> mTex;
  
          IDirect3DTexture9* mWhiteTex;
  
          ID3DXEffect* mFX;
          D3DXHANDLE   mhTech;
          D3DXHANDLE   mhWVP;
          D3DXHANDLE   mhWorldInvTrans;
          D3DXHANDLE   mhEyePos;
          D3DXHANDLE   mhWorld;
          D3DXHANDLE   mhTex;
          D3DXHANDLE   mhMtrl;
          D3DXHANDLE   mhLight;
  
          DirLight mLight;
  
          float mCameraRotationY;
          float mCameraRadius;
          float mCameraHeight;
  
          D3DXMATRIX mWorld;
  
          D3DXMATRIX mView;
          D3DXMATRIX mProj;
  };
  
  int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE prevInstance,
                                     PSTR cmdLine, int showCmd)
  {
          // Enable run-time memory check for debug builds.
          #if defined(DEBUG) | defined(_DEBUG)
                  _CrtSetDbgFlag( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );
          #endif
  
          XFileDemo app(hInstance, "XFile Demo", D3DDEVTYPE_HAL, D3DCREATE_HARDWARE_VERTEXPROCESSING);
          gd3dApp = &app;
  
          DirectInput di(DISCL_NONEXCLUSIVE|DISCL_FOREGROUND, DISCL_NONEXCLUSIVE|DISCL_FOREGROUND);
          gDInput = &di;
  
      return gd3dApp->run();
  }
  
  XFileDemo::XFileDemo(HINSTANCE hInstance, std::string winCaption, D3DDEVTYPE devType, DWORD requestedVP)
  : D3DApp(hInstance, winCaption, devType, requestedVP)
  {
          if(!checkDeviceCaps())
          {
                  MessageBox(0, "checkDeviceCaps() Failed", 0, 0);
                  PostQuitMessage(0);
          }
  
          InitAllVertexDeclarations();
  
          mGfxStats = new GfxStats();
          
          mCameraRadius    = 12.0f;
          mCameraRotationY = 1.2 * D3DX_PI;
          mCameraHeight    = 6.0f;
  
          mLight.dirW    = D3DXVECTOR3(0.0f, 1.0f, 2.0f);
          D3DXVec3Normalize(&mLight.dirW, &mLight.dirW);
          mLight.ambient = D3DXCOLOR(0.5f, 0.5f, 0.5f, 1.0f);
          mLight.diffuse = D3DXCOLOR(0.8f, 0.8f, 0.8f, 1.0f);
          mLight.spec    = D3DXCOLOR(0.8f, 0.8f, 0.8f, 1.0f);
  
          LoadXFile(<skullocc.x>, &mMesh, mMtrl, mTex);
          D3DXMatrixIdentity(&mWorld);
  
          HR(D3DXCreateTextureFromFile(gd3dDevice, "whitetex.dds", &mWhiteTex));
  
          mGfxStats->addVertices(mMesh->GetNumVertices());
          mGfxStats->addTriangles(mMesh->GetNumFaces());
  
          buildFX();
  
          onResetDevice();
  }
  
  XFileDemo::~XFileDemo()
  {
          delete mGfxStats;
          
          ReleaseCOM(mFX);
  
          ReleaseCOM(mMesh);
          for(int i = 0; i < mTex.size(); ++i)
                  ReleaseCOM(mTex[i]);
  
          ReleaseCOM(mWhiteTex);
  
          DestroyAllVertexDeclarations();
  }
  
  bool XFileDemo::checkDeviceCaps()
  {
          D3DCAPS9 caps;
          HR(gd3dDevice->GetDeviceCaps(&caps));
  
          // Check for vertex shader version 2.0 support.
          if( caps.VertexShaderVersion < D3DVS_VERSION(2, 0) )
                  return false;
  
          // Check for pixel shader version 2.0 support.
          if( caps.PixelShaderVersion < D3DPS_VERSION(2, 0) )
                  return false;
  
          return true;
  }
  
  void XFileDemo::onLostDevice()
  {
          mGfxStats->onLostDevice();
          HR(mFX->OnLostDevice());
  }
  
  void XFileDemo::onResetDevice()
  {
          mGfxStats->onResetDevice();
          HR(mFX->OnResetDevice());
  
          // The aspect ratio depends on the backbuffer dimensions, which can 
          // possibly change after a reset.  So rebuild the projection matrix.
          buildProjMtx();
  }
  
  void XFileDemo::updateScene(float dt)
  {
          mGfxStats->update(dt);
  
          // Get snapshot of input devices.
          gDInput->poll();
  
          // Check input.
          if( gDInput->keyDown(DIK_W) )         
                  mCameraHeight   += 25.0f * dt;
          if( gDInput->keyDown(DIK_S) )         
                  mCameraHeight   -= 25.0f * dt;
  
          // Divide by 50 to make mouse less sensitive. 
          mCameraRotationY += gDInput->mouseDX() / 100.0f;
          mCameraRadius    += gDInput->mouseDY() / 25.0f;
  
          // If we rotate over 360 degrees, just roll back to 0
          if( fabsf(mCameraRotationY) >= 2.0f * D3DX_PI ) 
                  mCameraRotationY = 0.0f;
  
          // Don't let radius get too small.
          if( mCameraRadius < 2.0f )
                  mCameraRadius = 2.0f;
  
          // The camera position/orientation relative to world space can 
          // change every frame based on input, so we need to rebuild the
          // view matrix every frame with the latest changes.
          buildViewMtx();
  }
  
  void XFileDemo::drawScene()
  {
          // Clear the backbuffer and depth buffer.
          HR(gd3dDevice->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffeeeeee, 1.0f, 0));
  
          HR(gd3dDevice->BeginScene());
  
          HR(mFX->SetValue(mhLight, &mLight, sizeof(DirLight)));
          HR(mFX->SetMatrix(mhWVP, &(mWorld*mView*mProj)));
          D3DXMATRIX worldInvTrans;
          D3DXMatrixInverse(&worldInvTrans, 0, &mWorld);
          D3DXMatrixTranspose(&worldInvTrans, &worldInvTrans);
          HR(mFX->SetMatrix(mhWorldInvTrans, &worldInvTrans));
          HR(mFX->SetMatrix(mhWorld, &mWorld));
  
          HR(mFX->SetTechnique(mhTech));
          UINT numPasses = 0;
          HR(mFX->Begin(&numPasses, 0));
          HR(mFX->BeginPass(0));
  
          for(int j = 0; j < mMtrl.size(); ++j)
          {
                  HR(mFX->SetValue(mhMtrl, &mMtrl[j], sizeof(Mtrl)));
          
                  // If there is a texture, then use.
                  if(mTex[j] != 0)
                  {
                          HR(mFX->SetTexture(mhTex, mTex[j]));
                  }
  
                  // But if not, then set a pure white texture.  When the texture color
                  // is multiplied by the color from lighting, it is like multiplying by
                  // 1 and won't change the color from lighting.
                  else
                  {
                          HR(mFX->SetTexture(mhTex, mWhiteTex));
                  }
          
                  HR(mFX->CommitChanges());
                  HR(mMesh->DrawSubset(j));
          }
          HR(mFX->EndPass());
          HR(mFX->End());
          
          mGfxStats->display();
  
          HR(gd3dDevice->EndScene());
  
          // Present the backbuffer.
          HR(gd3dDevice->Present(0, 0, 0, 0));
  }
  
  void XFileDemo::buildFX()
  {
          // Create the FX from a .fx file.
          ID3DXBuffer* errors = 0;
          HR(D3DXCreateEffectFromFile(gd3dDevice, "PhongDirLtTex.fx", 
                  0, 0, D3DXSHADER_DEBUG, 0, &mFX, &errors));
          if( errors )
                  MessageBox(0, (char*)errors->GetBufferPointer(), 0, 0);
  
          // Obtain handles.
          mhTech            = mFX->GetTechniqueByName("PhongDirLtTexTech");
          mhWVP             = mFX->GetParameterByName(0, "gWVP");
          mhWorldInvTrans   = mFX->GetParameterByName(0, "gWorldInvTrans");
          mhMtrl            = mFX->GetParameterByName(0, "gMtrl");
          mhLight           = mFX->GetParameterByName(0, "gLight");
          mhEyePos          = mFX->GetParameterByName(0, "gEyePosW");
          mhWorld           = mFX->GetParameterByName(0, "gWorld");
          mhTex             = mFX->GetParameterByName(0, "gTex");
  }
  
  void XFileDemo::buildViewMtx()
  {
          float x = mCameraRadius * cosf(mCameraRotationY);
          float z = mCameraRadius * sinf(mCameraRotationY);
          D3DXVECTOR3 pos(x, mCameraHeight, z);
          D3DXVECTOR3 target(0.0f, 2.0f, 0.0f);
          D3DXVECTOR3 up(0.0f, 1.0f, 0.0f);
          D3DXMatrixLookAtLH(&mView, &pos, &target, &up);
  
          HR(mFX->SetValue(mhEyePos, &pos, sizeof(D3DXVECTOR3)));
  }
  
  void XFileDemo::buildProjMtx()
  {
          float w = (float)md3dPP.BackBufferWidth;
          float h = (float)md3dPP.BackBufferHeight;
          D3DXMatrixPerspectiveFovLH(&mProj, D3DX_PI * 0.25f, w/h, 1.0f, 5000.0f);
  }