//=============================================================================
  // AmbientDiffuseDemo.cpp by Frank Luna (C) 2005 All Rights Reserved.
  //
  // Demonstrates diffuse and ambient lighting.
  //
  // 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 AmbientDiffuseDemo : public D3DApp
  {
  public:
          AmbientDiffuseDemo(HINSTANCE hInstance, std::string winCaption, D3DDEVTYPE devType, DWORD requestedVP);
          ~AmbientDiffuseDemo();
  
          bool checkDeviceCaps();
          void onLostDevice();
          void onResetDevice();
          void updateScene(float dt);
          void drawScene();
  
          // Helper methods
          void buildFX();
          void buildViewMtx();
          void buildProjMtx();
  
  private:
          GfxStats* mGfxStats;
          
          ID3DXMesh*   mTeapot;
          ID3DXEffect* mFX;
          D3DXHANDLE   mhTech;
          D3DXHANDLE   mhWVP;
          D3DXHANDLE   mhWorldInverseTranspose;
          D3DXHANDLE   mhLightVecW;
          D3DXHANDLE   mhDiffuseMtrl;
          D3DXHANDLE   mhDiffuseLight;
          D3DXHANDLE   mhAmbientMtrl;
          D3DXHANDLE   mhAmbientLight;
  
          D3DXVECTOR3 mLightVecW;
          D3DXCOLOR   mAmbientMtrl;
          D3DXCOLOR   mAmbientLight;
          D3DXCOLOR   mDiffuseMtrl;
          D3DXCOLOR   mDiffuseLight;
  
          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
  
          AmbientDiffuseDemo app(hInstance, "Ambient-Diffuse Demo", D3DDEVTYPE_HAL, D3DCREATE_HARDWARE_VERTEXPROCESSING);
          gd3dApp = &app;
  
          DirectInput di(DISCL_NONEXCLUSIVE|DISCL_FOREGROUND, DISCL_NONEXCLUSIVE|DISCL_FOREGROUND);
          gDInput = &di;
  
      return gd3dApp->run();
  }
  
  AmbientDiffuseDemo::AmbientDiffuseDemo(HINSTANCE hInstance, std::string winCaption, D3DDEVTYPE devType, DWORD requestedVP)
  : D3DApp(hInstance, winCaption, devType, requestedVP)
  {
          if(!checkDeviceCaps())
          {
                  MessageBox(0, "checkDeviceCaps() Failed", 0, 0);
                  PostQuitMessage(0);
          }
  
          mGfxStats = new GfxStats();
  
          mCameraRadius    = 10.0f;
          mCameraRotationY = 1.2 * D3DX_PI;
          mCameraHeight    = 5.0f;
  
          mLightVecW    = D3DXVECTOR3(0.0, 0.0f, -1.0f);
          mDiffuseMtrl  = D3DXCOLOR(0.0f, 0.0f, 1.0f, 1.0f);
          mDiffuseLight = D3DXCOLOR(1.0f, 1.0f, 1.0f, 1.0f);
          mAmbientMtrl  = D3DXCOLOR(0.0f, 0.0f, 1.0f, 1.0f);
          mAmbientLight = D3DXCOLOR(0.4f, 0.4f, 0.4f, 1.0f);
  
          D3DXMatrixIdentity(&mWorld);
  
          HR(D3DXCreateTeapot(gd3dDevice, &mTeapot, 0));
          buildFX();
  
          onResetDevice();
  
          InitAllVertexDeclarations();
  }
  
  AmbientDiffuseDemo::~AmbientDiffuseDemo()
  {
          delete mGfxStats;
          ReleaseCOM(mTeapot);
          ReleaseCOM(mFX);
  
          DestroyAllVertexDeclarations();
  }
  
  bool AmbientDiffuseDemo::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 AmbientDiffuseDemo::onLostDevice()
  {
          mGfxStats->onLostDevice();
          HR(mFX->OnLostDevice());
  }
  
  void AmbientDiffuseDemo::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 AmbientDiffuseDemo::updateScene(float dt)
  {
          mGfxStats->setVertexCount(mTeapot->GetNumVertices());
          mGfxStats->setTriCount(mTeapot->GetNumFaces());
          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 < 5.0f )
                  mCameraRadius = 5.0f;
  
          // 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 AmbientDiffuseDemo::drawScene()
  {
          // Clear the backbuffer and depth buffer.
          HR(gd3dDevice->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffeeeeee, 1.0f, 0));
  
          HR(gd3dDevice->BeginScene());
  
          // Setup the rendering FX
          HR(mFX->SetTechnique(mhTech));
  
          HR(mFX->SetMatrix(mhWVP, &(mWorld*mView*mProj)));
          D3DXMATRIX worldInverseTranspose;
          D3DXMatrixInverse(&worldInverseTranspose, 0, &mWorld);
          D3DXMatrixTranspose(&worldInverseTranspose, &worldInverseTranspose);
          HR(mFX->SetMatrix(mhWorldInverseTranspose, &worldInverseTranspose));
          HR(mFX->SetValue(mhLightVecW, &mLightVecW, sizeof(D3DXVECTOR3)));
          HR(mFX->SetValue(mhDiffuseMtrl, &mDiffuseMtrl, sizeof(D3DXCOLOR)));
          HR(mFX->SetValue(mhDiffuseLight, &mDiffuseLight, sizeof(D3DXCOLOR)));
          HR(mFX->SetValue(mhAmbientMtrl, &mAmbientMtrl, sizeof(D3DXCOLOR)));
          HR(mFX->SetValue(mhAmbientLight, &mAmbientLight, sizeof(D3DXCOLOR)));
  
          // Begin passes.
          UINT numPasses = 0;
          HR(mFX->Begin(&numPasses, 0));
          for(UINT i = 0; i < numPasses; ++i)
          {
                  HR(mFX->BeginPass(i));
                  HR(mTeapot->DrawSubset(0));
                  HR(mFX->EndPass());
          }
          HR(mFX->End());
  
          
          mGfxStats->display();
  
          HR(gd3dDevice->EndScene());
  
          // Present the backbuffer.
          HR(gd3dDevice->Present(0, 0, 0, 0));
  }
  
  void AmbientDiffuseDemo::buildFX()
  {
          // Create the FX from a .fx file.
          ID3DXBuffer* errors = 0;
          HR(D3DXCreateEffectFromFile(gd3dDevice, "ambientdiffuse.fx", 
                  0, 0, D3DXSHADER_DEBUG, 0, &mFX, &errors));
          if( errors )
                  MessageBox(0, (char*)errors->GetBufferPointer(), 0, 0);
  
          // Obtain handles.
          mhTech                  = mFX->GetTechniqueByName("AmbientDiffuseTech");
          mhWVP                   = mFX->GetParameterByName(0, "gWVP");
          mhWorldInverseTranspose = mFX->GetParameterByName(0, "gWorldInverseTranspose");
          mhLightVecW             = mFX->GetParameterByName(0, "gLightVecW");
          mhDiffuseMtrl           = mFX->GetParameterByName(0, "gDiffuseMtrl");
          mhDiffuseLight          = mFX->GetParameterByName(0, "gDiffuseLight");
          mhAmbientMtrl           = mFX->GetParameterByName(0, "gAmbientMtrl");
          mhAmbientLight          = mFX->GetParameterByName(0, "gAmbientLight");
  }
  
  void AmbientDiffuseDemo::buildViewMtx()
  {
          float x = mCameraRadius * cosf(mCameraRotationY);
          float z = mCameraRadius * sinf(mCameraRotationY);
          D3DXVECTOR3 pos(x, mCameraHeight, z);
          D3DXVECTOR3 target(0.0f, 0.0f, 0.0f);
          D3DXVECTOR3 up(0.0f, 1.0f, 0.0f);
          D3DXMatrixLookAtLH(&mView, &pos, &target, &up);
  }
  
  void AmbientDiffuseDemo::buildProjMtx()
  {
          float w = (float)md3dPP.BackBufferWidth;
          float h = (float)md3dPP.BackBufferHeight;
          D3DXMatrixPerspectiveFovLH(&mProj, D3DX_PI * 0.25f, w/h, 1.0f, 5000.0f);
  }