//=============================================================================
  // CubeDemo.cpp by Frank Luna (C) 2005 All Rights Reserved.
  //
  // Demonstrates how to create the geometry of a cube and draw it.
  //
  // 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 CubeDemo : public D3DApp
  {
  public:
          CubeDemo(HINSTANCE hInstance, std::string winCaption, D3DDEVTYPE devType, DWORD requestedVP);
          ~CubeDemo();
  
          bool checkDeviceCaps();
          void onLostDevice();
          void onResetDevice();
          void updateScene(float dt);
          void drawScene();
  
          // Helper methods
          void buildVertexBuffer();
          void buildIndexBuffer();
          void buildViewMtx();
          void buildProjMtx();
  
  private:
          GfxStats* mGfxStats;
          
          IDirect3DVertexBuffer9* mVB;
          IDirect3DIndexBuffer9*  mIB;
  
          float mCameraRotationY;
          float mCameraRadius;
          float mCameraHeight;
  
          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
  
          CubeDemo app(hInstance, "Cube Demo", D3DDEVTYPE_HAL, D3DCREATE_HARDWARE_VERTEXPROCESSING);
          gd3dApp = &app;
  
          DirectInput di(DISCL_NONEXCLUSIVE|DISCL_FOREGROUND, DISCL_NONEXCLUSIVE|DISCL_FOREGROUND);
          gDInput = &di;
  
          return gd3dApp->run();
  }
  
  CubeDemo::CubeDemo(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;
  
          buildVertexBuffer();
          buildIndexBuffer();
  
          onResetDevice();
  
          InitAllVertexDeclarations();
  }
  
  CubeDemo::~CubeDemo()
  {
          delete mGfxStats;
          ReleaseCOM(mVB);
          ReleaseCOM(mIB);
  
          DestroyAllVertexDeclarations();
  }
  
  bool CubeDemo::checkDeviceCaps()
  {
          return true;
  }
  
  void CubeDemo::onLostDevice()
  {
          mGfxStats->onLostDevice();
  }
  
  void CubeDemo::onResetDevice()
  {
          mGfxStats->onResetDevice();
  
          // The aspect ratio depends on the backbuffer dimensions, which can 
          // possibly change after a reset.  So rebuild the projection matrix.
          buildProjMtx();
  }
  
  void CubeDemo::updateScene(float dt)
  {
          // One cube has 8 vertice and 12 triangles.
          mGfxStats->setVertexCount(8);
          mGfxStats->setTriCount(12);
          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 CubeDemo::drawScene()
  {
          // Clear the backbuffer and depth buffer.
          HR(gd3dDevice->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffffffff, 1.0f, 0));
  
          HR(gd3dDevice->BeginScene());
  
          // Let Direct3D know the vertex buffer, index buffer and vertex 
          // declaration we are using.
          HR(gd3dDevice->SetStreamSource(0, mVB, 0, sizeof(VertexPos)));
          HR(gd3dDevice->SetIndices(mIB));
          HR(gd3dDevice->SetVertexDeclaration(VertexPos::Decl));
  
          // World matrix is identity.
          D3DXMATRIX W;
          D3DXMatrixIdentity(&W);
          HR(gd3dDevice->SetTransform(D3DTS_WORLD, &W));
          HR(gd3dDevice->SetTransform(D3DTS_VIEW, &mView));
          HR(gd3dDevice->SetTransform(D3DTS_PROJECTION, &mProj));
  
          HR(gd3dDevice->SetRenderState(D3DRS_FILLMODE, D3DFILL_WIREFRAME));
          HR(gd3dDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, 0, 0, 8, 0, 12));
          
          mGfxStats->display();
  
          HR(gd3dDevice->EndScene());
  
          // Present the backbuffer.
          HR(gd3dDevice->Present(0, 0, 0, 0));
  }
  
  void CubeDemo::buildVertexBuffer()
  {
          // Obtain a pointer to a new vertex buffer.
          HR(gd3dDevice->CreateVertexBuffer(8 * sizeof(VertexPos), D3DUSAGE_WRITEONLY,
                  0, D3DPOOL_MANAGED, &mVB, 0));
  
          // Now lock it to obtain a pointer to its internal data, and write the
          // cube's vertex data.
  
          VertexPos* v = 0;
          HR(mVB->Lock(0, 0, (void**)&v, 0));
  
          v[0] = VertexPos(-1.0f, -1.0f, -1.0f);
          v[1] = VertexPos(-1.0f,  1.0f, -1.0f);
          v[2] = VertexPos( 1.0f,  1.0f, -1.0f);
          v[3] = VertexPos( 1.0f, -1.0f, -1.0f);
          v[4] = VertexPos(-1.0f, -1.0f,  1.0f);
          v[5] = VertexPos(-1.0f,  1.0f,  1.0f);
          v[6] = VertexPos( 1.0f,  1.0f,  1.0f);
          v[7] = VertexPos( 1.0f, -1.0f,  1.0f);
  
          HR(mVB->Unlock());
  }
  
  void CubeDemo::buildIndexBuffer()
  {
          // Obtain a pointer to a new index buffer.
          HR(gd3dDevice->CreateIndexBuffer(36 * sizeof(WORD), D3DUSAGE_WRITEONLY,
                  D3DFMT_INDEX16, D3DPOOL_MANAGED, &mIB, 0));
  
          // Now lock it to obtain a pointer to its internal data, and write the
          // cube's index data.
  
          WORD* k = 0;
  
          HR(mIB->Lock(0, 0, (void**)&k, 0));
  
          // Front face.
          k[0] = 0; k[1] = 1; k[2] = 2;
          k[3] = 0; k[4] = 2; k[5] = 3;
  
          // Back face.
          k[6] = 4; k[7]  = 6; k[8]  = 5;
          k[9] = 4; k[10] = 7; k[11] = 6;
  
          // Left face.
          k[12] = 4; k[13] = 5; k[14] = 1;
          k[15] = 4; k[16] = 1; k[17] = 0;
  
          // Right face.
          k[18] = 3; k[19] = 2; k[20] = 6;
          k[21] = 3; k[22] = 6; k[23] = 7;
  
          // Top face.
          k[24] = 1; k[25] = 5; k[26] = 6;
          k[27] = 1; k[28] = 6; k[29] = 2;
  
          // Bottom face.
          k[30] = 4; k[31] = 0; k[32] = 3;
          k[33] = 4; k[34] = 3; k[35] = 7;
  
          HR(mIB->Unlock());
  }
  
  void CubeDemo::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 CubeDemo::buildProjMtx()
  {
          float w = (float)md3dPP.BackBufferWidth;
          float h = (float)md3dPP.BackBufferHeight;
          D3DXMatrixPerspectiveFovLH(&mProj, D3DX_PI * 0.25f, w/h, 1.0f, 5000.0f);
  }