//=============================================================================
  // SolarSysDemo.cpp by Frank Luna (C) 2005 All Rights Reserved.
  //
  // Another demonstrates of how to animate mesh hierarchies.
  //
  // 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>
  
  // We classify the objects in our scene as one of three types.
  enum SolarType
  {
          SUN,
          PLANET,
          MOON
  };
  
  struct SolarObject
  {
          void set(SolarType type, D3DXVECTOR3 p, float yRot, int parentIndex, float s, IDirect3DTexture9* t)
          {
                  typeID = type;
                  pos    = p;
                  yAngle = yRot;
                  parent = parentIndex;
                  size   = s;
                  tex    = t;
          }
  
          // Note: The root's "parent" frame is the world space.
  
          SolarType typeID;
          D3DXVECTOR3 pos;  // Relative to parent frame.
          float yAngle;     // Relative to parent frame.
          int parent;       // Index to parent frame (-1 if root, i.e., no parent)
          float size;       // Relative to world frame.
          IDirect3DTexture9* tex;
          D3DXMATRIX toParentXForm;
          D3DXMATRIX toWorldXForm;
  };
  
  class SolarSysDemo : public D3DApp
  {
  public:
          SolarSysDemo(HINSTANCE hInstance, std::string winCaption, D3DDEVTYPE devType, DWORD requestedVP);
          ~SolarSysDemo();
  
          bool checkDeviceCaps();
          void onLostDevice();
          void onResetDevice();
          void updateScene(float dt);
          void drawScene();
  
          // Helper methods
          void buildFX();
          void buildViewMtx();
          void buildProjMtx();
  
          void buildObjectWorldTransforms();
  
          void genSphericalTexCoords();
  
  private:
          GfxStats* mGfxStats;
          
          // We only need one sphere mesh.  To draw several solar objects we just 
          // draw the same mesh several times, but with a different transformation
          // applied so that it is drawn in a different place.
          ID3DXMesh* mSphere;
   
          static const int NUM_OBJECTS = 10;
          SolarObject mObject[NUM_OBJECTS];
          
          IDirect3DTexture9* mSunTex;
          IDirect3DTexture9* mPlanet1Tex;
          IDirect3DTexture9* mPlanet2Tex;
          IDirect3DTexture9* mPlanet3Tex;
          IDirect3DTexture9* mMoonTex;
  
          // Use a white material--the color will come from the texture.
          Mtrl mWhiteMtrl;
  
          DirLight mLight;
  
          ID3DXEffect* mFX;
          D3DXHANDLE   mhTech;
          D3DXHANDLE   mhWVP;
          D3DXHANDLE   mhWorldInvTrans;
          D3DXHANDLE   mhEyePos;
          D3DXHANDLE   mhWorld;
          D3DXHANDLE   mhTex;
          D3DXHANDLE   mhMtrl;
          D3DXHANDLE   mhLight;
  
          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
  
          SolarSysDemo app(hInstance, "Solar System Demo", D3DDEVTYPE_HAL, D3DCREATE_HARDWARE_VERTEXPROCESSING);
          gd3dApp = &app;
  
          DirectInput di(DISCL_NONEXCLUSIVE|DISCL_FOREGROUND, DISCL_NONEXCLUSIVE|DISCL_FOREGROUND);
          gDInput = &di;
  
      return gd3dApp->run();
  }
  
  SolarSysDemo::SolarSysDemo(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();
          
          // Initialize Camera Settings
          mCameraRadius    = 25.0f;
          mCameraRotationY = 1.2f * D3DX_PI;
          mCameraHeight    = 10.0f;
  
          // Setup a directional light.
          mLight.dirW    = D3DXVECTOR3(0.0f, 1.0f, 2.0f);
          D3DXVec3Normalize(&mLight.dirW, &mLight.dirW);
          mLight.ambient = D3DXCOLOR(1.0f, 1.0f, 1.0f, 1.0f);
          mLight.diffuse = D3DXCOLOR(1.0f, 1.0f, 1.0f, 1.0f);
          mLight.spec    = D3DXCOLOR(0.6f, 0.6f, 0.6f, 1.0f);
  
          // Create a sphere to represent a solar object.
          HR(D3DXCreateSphere(gd3dDevice, 1.0f, 30, 30, &mSphere, 0));
          genSphericalTexCoords();
          D3DXMatrixIdentity(&mWorld);
  
          // Create the textures.
          HR(D3DXCreateTextureFromFile(gd3dDevice, "sun.dds", &mSunTex));
          HR(D3DXCreateTextureFromFile(gd3dDevice, "planet1.dds", &mPlanet1Tex));
          HR(D3DXCreateTextureFromFile(gd3dDevice, "planet2.dds", &mPlanet2Tex));
          HR(D3DXCreateTextureFromFile(gd3dDevice, "planet3.dds", &mPlanet3Tex));
          HR(D3DXCreateTextureFromFile(gd3dDevice, "moon.dds", &mMoonTex));
  
          // Initialize default white material.
          mWhiteMtrl.ambient = WHITE;
          mWhiteMtrl.diffuse = WHITE;
          mWhiteMtrl.spec    = WHITE * 0.5f;
          mWhiteMtrl.specPower = 48.0f;
  
          //==================================================
          // Specify how the solar object frames are related.
  
          D3DXVECTOR3 pos[NUM_OBJECTS] = 
          {
                  D3DXVECTOR3(0.0f, 0.0f, 0.0f),
                  D3DXVECTOR3(7.0f, 0.0f, 7.0f),
                  D3DXVECTOR3(-9.0f, 0.0f, 0.0f),
                  D3DXVECTOR3(7.0f, 0.0f, -6.0f),
                  D3DXVECTOR3(5.0f, 0.0f, 0.0f),
                  D3DXVECTOR3(-5.0f, 0.0f, 0.0f),
                  D3DXVECTOR3(3.0f, 0.0f, 0.0f),
                  D3DXVECTOR3(2.0f, 0.0f, -2.0f),
                  D3DXVECTOR3(-2.0f, 0.0f, 0.0f),
                  D3DXVECTOR3(0.0f, 0.0f, 2.0f)
          };
  
          mObject[0].set(SUN, pos[0], 0.0f, -1, 2.5f, mSunTex);  // Sun
          mObject[1].set(PLANET, pos[1], 0.0f, 0, 1.5f, mPlanet1Tex);// P1
          mObject[2].set(PLANET, pos[2], 0.0f, 0, 1.2f, mPlanet2Tex);// P2
          mObject[3].set(PLANET, pos[3], 0.0f, 0, 0.8f, mPlanet3Tex);// P3
  
          mObject[4].set(MOON, pos[4], 0.0f, 1, 0.5f, mMoonTex); // M1P1
          mObject[5].set(MOON, pos[5], 0.0f, 1, 0.5f, mMoonTex); // M2P1
          mObject[6].set(MOON, pos[6], 0.0f, 2, 0.4f, mMoonTex); // M1P2
          mObject[7].set(MOON, pos[7], 0.0f, 3, 0.3f, mMoonTex); // M1P3
          mObject[8].set(MOON, pos[8], 0.0f, 3, 0.3f, mMoonTex); // M2P3
          mObject[9].set(MOON, pos[9], 0.0f, 3, 0.3f, mMoonTex); // M3P3
  
          //==================================================
   
          mGfxStats->addVertices(mSphere->GetNumVertices() * NUM_OBJECTS);
          mGfxStats->addTriangles(mSphere->GetNumFaces() * NUM_OBJECTS);
  
          buildFX();
  
          onResetDevice();
  }
  
  SolarSysDemo::~SolarSysDemo()
  {
          delete mGfxStats;
          
          ReleaseCOM(mFX);
          ReleaseCOM(mSphere);
          ReleaseCOM(mSunTex);
          ReleaseCOM(mPlanet1Tex);
          ReleaseCOM(mPlanet2Tex);
          ReleaseCOM(mPlanet3Tex);
          ReleaseCOM(mMoonTex);
  
          DestroyAllVertexDeclarations();
  }
  
  bool SolarSysDemo::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 SolarSysDemo::onLostDevice()
  {
          mGfxStats->onLostDevice();
          HR(mFX->OnLostDevice());
  }
  
  void SolarSysDemo::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 SolarSysDemo::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();
  
          //================================================
          // Animate the solar objects with respect to time.
  
          for(int i = 0; i < NUM_OBJECTS; ++i)
          {
                  switch(mObject[i].typeID)
                  {
                  case SUN:
                          mObject[i].yAngle += 1.5f * dt;
                          break;
                  case PLANET:
                          mObject[i].yAngle += 2.0f * dt;
                          break;
                  case MOON:
                          mObject[i].yAngle += 2.5f * dt;
                          break;
                  }
  
                  // If we rotate over 360 degrees, just roll back to 0.
                  if(mObject[i].yAngle >= 2.0f*D3DX_PI)
                          mObject[i].yAngle = 0.0f;
          }
  }
  
  void SolarSysDemo::drawScene()
  {
          // Clear the backbuffer and depth buffer.
          HR(gd3dDevice->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xff000000, 1.0f, 0));
  
          HR(gd3dDevice->BeginScene());
  
          HR(mFX->SetValue(mhLight, &mLight, sizeof(DirLight)));
  
          HR(mFX->SetTechnique(mhTech));
          UINT numPasses = 0;
          HR(mFX->Begin(&numPasses, 0));
          HR(mFX->BeginPass(0));
  
          // Wrap the texture coordinates that get assigned to TEXCOORD2 in the pixel shader.
          HR(gd3dDevice->SetRenderState(D3DRS_WRAP2, D3DWRAP_U));
  
          // Build the world transforms for each frame, then render them.
          buildObjectWorldTransforms();
          D3DXMATRIX S;
          for(int i = 0; i < NUM_OBJECTS; ++i)
          {
                  float s = mObject[i].size;
                  D3DXMatrixScaling(&S, s, s, s);
  
                  // Prefix the frame matrix with a scaling transformation to
                  // size it relative to the world.
                  mWorld = S * mObject[i].toWorldXForm;
                  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->SetValue(mhMtrl, &mWhiteMtrl, sizeof(Mtrl)));
                  HR(mFX->SetTexture(mhTex, mObject[i].tex));        
                  HR(mFX->CommitChanges());
                  
                  mSphere->DrawSubset(0);
          }
          HR(gd3dDevice->SetRenderState(D3DRS_WRAP2, 0));
          HR(mFX->EndPass());
          HR(mFX->End());
          
          mGfxStats->display();
  
          HR(gd3dDevice->EndScene());
  
          // Present the backbuffer.
          HR(gd3dDevice->Present(0, 0, 0, 0));
  }
  
  void SolarSysDemo::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 SolarSysDemo::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);
  
          HR(mFX->SetValue(mhEyePos, &pos, sizeof(D3DXVECTOR3)));
  }
  
  void SolarSysDemo::buildProjMtx()
  {
          float w = (float)md3dPP.BackBufferWidth;
          float h = (float)md3dPP.BackBufferHeight;
          D3DXMatrixPerspectiveFovLH(&mProj, D3DX_PI * 0.25f, w/h, 1.0f, 5000.0f);
  }
  
  void SolarSysDemo::buildObjectWorldTransforms()
  {
          // First, construct the transformation matrix that transforms
          // the ith bone into the coordinate system of its parent.
  
          D3DXMATRIX R, T;
          D3DXVECTOR3 p;
          for(int i = 0; i < NUM_OBJECTS; ++i) 
          {
                  p = mObject[i].pos;
                  D3DXMatrixRotationY(&R, mObject[i].yAngle);
                  D3DXMatrixTranslation(&T, p.x, p.y, p.z);
                  mObject[i].toParentXForm = R * T;
          }
  
          // For each object...
          for(int i = 0; i < NUM_OBJECTS; ++i)
          {
                  // Initialize to identity matrix.
                  D3DXMatrixIdentity(&mObject[i].toWorldXForm);
  
                  // The ith object's world transform is given by its 
                  // to-parent transform, followed by its parent's to-parent transform, 
                  // followed by its grandparent's to-parent transform, and
                  // so on, up to the root's to-parent transform.
                  int k = i;
                  while( k != -1 )
                  {
                          mObject[i].toWorldXForm *= mObject[k].toParentXForm;
                          k = mObject[k].parent;
                  }
          }
  }
  
  void SolarSysDemo::genSphericalTexCoords()
  {
          // D3DXCreate* functions generate vertices with position 
          // and normal data.  But for texturing, we also need
          // tex-coords.  So clone the mesh to change the vertex
          // format to a format with tex-coords.
  
          D3DVERTEXELEMENT9 elements[64];
          UINT numElements = 0;
          VertexPNT::Decl->GetDeclaration(elements, &numElements);
  
          ID3DXMesh* temp = 0;
          HR(mSphere->CloneMesh(D3DXMESH_SYSTEMMEM, 
                  elements, gd3dDevice, &temp));
  
          ReleaseCOM(mSphere);
  
          // Now generate texture coordinates for each vertex.
          VertexPNT* vertices = 0;
          HR(temp->LockVertexBuffer(0, (void**)&vertices));
  
          for(UINT i = 0; i < temp->GetNumVertices(); ++i)
          {
                  // Convert to spherical coordinates.
                  D3DXVECTOR3 p = vertices[i].pos;
          
   
                  float theta = atan2f(p.z, p.x);
                  float phi   = acosf(p.y / sqrtf(p.x*p.x+p.y*p.y+p.z*p.z));
  
                  // Phi and theta give the texture coordinates, but are not in 
                  // the range [0, 1], so scale them into that range.
  
                  float u = theta / (2.0f*D3DX_PI);
                  float v = phi   / D3DX_PI;
                  
                  // Save texture coordinates.
                  
                  vertices[i].tex0.x = u;
                  vertices[i].tex0.y = v;
          }
          HR(temp->UnlockVertexBuffer());
  
          // Clone back to a hardware mesh.
          HR(temp->CloneMesh(D3DXMESH_MANAGED | D3DXMESH_WRITEONLY,
                  elements, gd3dDevice, &mSphere));
  
          ReleaseCOM(temp);
  }