//=============================================================================
  // CloudDemo.cpp by Frank Luna (C) 2005 All Rights Reserved.
  //
  // Demonstrates texture animation by scrolling two cloud textures.
  //
  // 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 CloudDemo : public D3DApp
  {
  public:
          CloudDemo(HINSTANCE hInstance, std::string winCaption, D3DDEVTYPE devType, DWORD requestedVP);
          ~CloudDemo();
  
          bool checkDeviceCaps();
          void onLostDevice();
          void onResetDevice();
          void updateScene(float dt);
          void drawScene();
  
          // Helper methods
          void buildGridGeometry();
          void buildFX();
          void buildViewMtx();
          void buildProjMtx();
  
  private:
          GfxStats* mGfxStats;
  
          DWORD mNumGridVertices;
          DWORD mNumGridTriangles;
          
          IDirect3DVertexBuffer9* mGridVB;
          IDirect3DIndexBuffer9*  mGridIB;
          IDirect3DTexture9*      mCloudTex0;
          IDirect3DTexture9*      mCloudTex1;
  
          ID3DXEffect* mFX;
          D3DXHANDLE   mhTech;
          D3DXHANDLE   mhWVP;
          D3DXHANDLE   mhCloudTex0;
          D3DXHANDLE   mhCloudTex1;
          D3DXHANDLE   mhTexOffset0;
          D3DXHANDLE   mhTexOffset1;
  
          D3DXVECTOR2 mTexOffset0;
          D3DXVECTOR2 mTexOffset1;
  
          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
  
          CloudDemo app(hInstance, "Cloud Demo", D3DDEVTYPE_HAL, D3DCREATE_HARDWARE_VERTEXPROCESSING);
          gd3dApp = &app;
  
          DirectInput di(DISCL_NONEXCLUSIVE|DISCL_FOREGROUND, DISCL_NONEXCLUSIVE|DISCL_FOREGROUND);
          gDInput = &di;
  
      return gd3dApp->run();
  }
  
  CloudDemo::CloudDemo(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    = 30.0f;
          mCameraRotationY = 1.2 * D3DX_PI;
          mCameraHeight    = 15.0f;
  
          D3DXMatrixIdentity(&mWorld);
  
          HR(D3DXCreateTextureFromFile(gd3dDevice, "cloud0.dds", &mCloudTex0));
          HR(D3DXCreateTextureFromFile(gd3dDevice, "cloud1.dds", &mCloudTex1));
  
          mTexOffset0 = D3DXVECTOR2(0.0f, 0.0f);
          mTexOffset1 = D3DXVECTOR2(0.0f, 0.0f);
  
          buildGridGeometry();
          mGfxStats->addVertices(mNumGridVertices);
          mGfxStats->addTriangles(mNumGridTriangles);
  
          buildFX();
  
          onResetDevice();
  
          InitAllVertexDeclarations();
  }
  
  CloudDemo::~CloudDemo()
  {
          delete mGfxStats;
          ReleaseCOM(mGridVB);
          ReleaseCOM(mGridIB);
          ReleaseCOM(mCloudTex0);
          ReleaseCOM(mCloudTex1);
          ReleaseCOM(mFX);
  
          DestroyAllVertexDeclarations();
  }
  
  bool CloudDemo::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 CloudDemo::onLostDevice()
  {
          mGfxStats->onLostDevice();
          HR(mFX->OnLostDevice());
  }
  
  void CloudDemo::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 CloudDemo::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 < 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();
  
          // Update texture coordinate offsets.  These offsets are added to the
          // texture coordinates in the vertex shader to animate them.
          mTexOffset0 += D3DXVECTOR2(0.11f, 0.05f) * dt;
          mTexOffset1 += D3DXVECTOR2(0.25f, 0.1f) * dt;
  
          // Textures repeat every 1.0 unit, so reset back down to zero
          // so the coordinates do not grow.
          if(mTexOffset0.x >= 1.0f || mTexOffset0.x <= -1.0f)
                  mTexOffset0.x = 0.0f;
          if(mTexOffset1.x >= 1.0f || mTexOffset1.x <= -1.0f)
                  mTexOffset1.x = 0.0f;
          if(mTexOffset0.y >= 1.0f || mTexOffset0.y <= -1.0f)
                  mTexOffset0.y = 0.0f;
          if(mTexOffset1.y >= 1.0f || mTexOffset1.y <= -1.0f)
                  mTexOffset1.y = 0.0f;
  }
  
  void CloudDemo::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)));
          HR(mFX->SetTexture(mhCloudTex0, mCloudTex0));
          HR(mFX->SetTexture(mhCloudTex1, mCloudTex1));
          HR(mFX->SetValue(mhTexOffset0, &mTexOffset0, sizeof(D3DXVECTOR2)));
          HR(mFX->SetValue(mhTexOffset1, &mTexOffset1, sizeof(D3DXVECTOR2)));
  
          HR(gd3dDevice->SetVertexDeclaration(VertexPT::Decl));
          HR(gd3dDevice->SetStreamSource(0, mGridVB, 0, sizeof(VertexPT)));
          HR(gd3dDevice->SetIndices(mGridIB));
  
          // Begin passes.
          UINT numPasses = 0;
          HR(mFX->Begin(&numPasses, 0));
          for(UINT i = 0; i < numPasses; ++i)
          {
                  HR(mFX->BeginPass(i));
                  HR(gd3dDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, 0, 0, mNumGridVertices, 0, mNumGridTriangles));
                  HR(mFX->EndPass());
          }
          HR(mFX->End());
  
          
          mGfxStats->display();
  
          HR(gd3dDevice->EndScene());
  
          // Present the backbuffer.
          HR(gd3dDevice->Present(0, 0, 0, 0));
  }
  
  void CloudDemo::buildGridGeometry()
  {
          std::vector<D3DXVECTOR3> verts;
          std::vector<DWORD> indices;
  
          GenTriGrid(100, 100, 1.0f, 1.0f, 
                  D3DXVECTOR3(0.0f, 0.0f, 0.0f), verts, indices);
  
          // Save vertex count and triangle count for DrawIndexedPrimitive arguments.
          mNumGridVertices  = 100*100;
          mNumGridTriangles = 99*99*2;
  
          // Obtain a pointer to a new vertex buffer.
          HR(gd3dDevice->CreateVertexBuffer(mNumGridVertices * sizeof(VertexPT), 
                  D3DUSAGE_WRITEONLY,        0, D3DPOOL_MANAGED, &mGridVB, 0));
  
          // Now lock it to obtain a pointer to its internal data, and write the
          // grid's vertex data.
          VertexPT* v = 0;
          HR(mGridVB->Lock(0, 0, (void**)&v, 0));
  
          float texScale = 0.02f;
          for(int i = 0; i < 100; ++i)
          {
                  for(int j = 0; j < 100; ++j)
                  {
                          DWORD index = i * 100 + j;
                          v[index].pos  = verts[index];
                          v[index].tex0 = D3DXVECTOR2((float)j, (float)i) * texScale;
                  }
          }
  
          HR(mGridVB->Unlock());
  
          // Obtain a pointer to a new index buffer.
          HR(gd3dDevice->CreateIndexBuffer(mNumGridTriangles*3*sizeof(WORD), D3DUSAGE_WRITEONLY,
                  D3DFMT_INDEX16, D3DPOOL_MANAGED, &mGridIB, 0));
  
          // Now lock it to obtain a pointer to its internal data, and write the
          // grid's index data.
  
          WORD* k = 0;
          HR(mGridIB->Lock(0, 0, (void**)&k, 0));
  
          for(DWORD i = 0; i < mNumGridTriangles*3; ++i)
                  k[i] = (WORD)indices[i];
  
          HR(mGridIB->Unlock());
  }
  
  void CloudDemo::buildFX()
  {
          // Create the FX from a .fx file.
          ID3DXBuffer* errors = 0;
          HR(D3DXCreateEffectFromFile(gd3dDevice, "clouds.fx", 
                  0, 0, D3DXSHADER_DEBUG, 0, &mFX, &errors));
          if( errors )
                  MessageBox(0, (char*)errors->GetBufferPointer(), 0, 0);
  
          // Obtain handles.
          mhTech       = mFX->GetTechniqueByName("CloudsTech");
          mhWVP        = mFX->GetParameterByName(0, "gWVP");
          mhCloudTex0  = mFX->GetParameterByName(0, "gCloudTex0");
          mhCloudTex1  = mFX->GetParameterByName(0, "gCloudTex1");
          mhTexOffset0 = mFX->GetParameterByName(0, "gTexOffset0");
          mhTexOffset1 = mFX->GetParameterByName(0, "gTexOffset1");
  }
  
  void CloudDemo::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 CloudDemo::buildProjMtx()
  {
          float w = (float)md3dPP.BackBufferWidth;
          float h = (float)md3dPP.BackBufferHeight;
          D3DXMatrixPerspectiveFovLH(&mProj, D3DX_PI * 0.25f, w/h, 1.0f, 5000.0f);
  }