//-----------------------------------------------------------------------------
TCHAR* D3DUtil_D3DFormatToString( D3DFORMAT format, bool bWithPrefix )
{
    TCHAR* pstr = NULL;
    switch( format )
    {
    case D3DFMT_UNKNOWN:         pstr = TEXT("D3DFMT_UNKNOWN"); break;
    case D3DFMT_R8G8B8:          pstr = TEXT("D3DFMT_R8G8B8"); break;
    case D3DFMT_A8R8G8B8:        pstr = TEXT("D3DFMT_A8R8G8B8"); break;
    case D3DFMT_X8R8G8B8:        pstr = TEXT("D3DFMT_X8R8G8B8"); break;
    case D3DFMT_R5G6B5:          pstr = TEXT("D3DFMT_R5G6B5"); break;
    case D3DFMT_X1R5G5B5:        pstr = TEXT("D3DFMT_X1R5G5B5"); break;
    case D3DFMT_A1R5G5B5:        pstr = TEXT("D3DFMT_A1R5G5B5"); break;
    case D3DFMT_A4R4G4B4:        pstr = TEXT("D3DFMT_A4R4G4B4"); break;
    case D3DFMT_R3G3B2:          pstr = TEXT("D3DFMT_R3G3B2"); break;
    case D3DFMT_A8:              pstr = TEXT("D3DFMT_A8"); break;
    case D3DFMT_A8R3G3B2:        pstr = TEXT("D3DFMT_A8R3G3B2"); break;
    case D3DFMT_X4R4G4B4:        pstr = TEXT("D3DFMT_X4R4G4B4"); break;
    case D3DFMT_A2B10G10R10:     pstr = TEXT("D3DFMT_A2B10G10R10"); break;
    case D3DFMT_A8B8G8R8:        pstr = TEXT("D3DFMT_A8B8G8R8"); break;
    case D3DFMT_X8B8G8R8:        pstr = TEXT("D3DFMT_X8B8G8R8"); break;
    case D3DFMT_G16R16:          pstr = TEXT("D3DFMT_G16R16"); break;
    case D3DFMT_A2R10G10B10:     pstr = TEXT("D3DFMT_A2R10G10B10"); break;
    case D3DFMT_A16B16G16R16:    pstr = TEXT("D3DFMT_A16B16G16R16"); break;
    case D3DFMT_A8P8:            pstr = TEXT("D3DFMT_A8P8"); break;
    case D3DFMT_P8:              pstr = TEXT("D3DFMT_P8"); break;
    case D3DFMT_L8:              pstr = TEXT("D3DFMT_L8"); break;
    case D3DFMT_A8L8:            pstr = TEXT("D3DFMT_A8L8"); break;
    case D3DFMT_A4L4:            pstr = TEXT("D3DFMT_A4L4"); break;
    case D3DFMT_V8U8:            pstr = TEXT("D3DFMT_V8U8"); break;
    case D3DFMT_L6V5U5:          pstr = TEXT("D3DFMT_L6V5U5"); break;
    case D3DFMT_X8L8V8U8:        pstr = TEXT("D3DFMT_X8L8V8U8"); break;
    case D3DFMT_Q8W8V8U8:        pstr = TEXT("D3DFMT_Q8W8V8U8"); break;
    case D3DFMT_V16U16:          pstr = TEXT("D3DFMT_V16U16"); break;
    case D3DFMT_A2W10V10U10:     pstr = TEXT("D3DFMT_A2W10V10U10"); break;
    case D3DFMT_UYVY:            pstr = TEXT("D3DFMT_UYVY"); break;
    case D3DFMT_YUY2:            pstr = TEXT("D3DFMT_YUY2"); break;
    case D3DFMT_DXT1:            pstr = TEXT("D3DFMT_DXT1"); break;
    case D3DFMT_DXT2:            pstr = TEXT("D3DFMT_DXT2"); break;
    case D3DFMT_DXT3:            pstr = TEXT("D3DFMT_DXT3"); break;
    case D3DFMT_DXT4:            pstr = TEXT("D3DFMT_DXT4"); break;
    case D3DFMT_DXT5:            pstr = TEXT("D3DFMT_DXT5"); break;
    case D3DFMT_D16_LOCKABLE:    pstr = TEXT("D3DFMT_D16_LOCKABLE"); break;
    case D3DFMT_D32:             pstr = TEXT("D3DFMT_D32"); break;
    case D3DFMT_D15S1:           pstr = TEXT("D3DFMT_D15S1"); break;
    case D3DFMT_D24S8:           pstr = TEXT("D3DFMT_D24S8"); break;
    case D3DFMT_D24X8:           pstr = TEXT("D3DFMT_D24X8"); break;
    case D3DFMT_D24X4S4:         pstr = TEXT("D3DFMT_D24X4S4"); break;
    case D3DFMT_D16:             pstr = TEXT("D3DFMT_D16"); break;
    case D3DFMT_L16:             pstr = TEXT("D3DFMT_L16"); break;
    case D3DFMT_VERTEXDATA:      pstr = TEXT("D3DFMT_VERTEXDATA"); break;
    case D3DFMT_INDEX16:         pstr = TEXT("D3DFMT_INDEX16"); break;
    case D3DFMT_INDEX32:         pstr = TEXT("D3DFMT_INDEX32"); break;
    case D3DFMT_Q16W16V16U16:    pstr = TEXT("D3DFMT_Q16W16V16U16"); break;
    case D3DFMT_MULTI2_ARGB8:    pstr = TEXT("D3DFMT_MULTI2_ARGB8"); break;
    case D3DFMT_R16F:            pstr = TEXT("D3DFMT_R16F"); break;
    case D3DFMT_G16R16F:         pstr = TEXT("D3DFMT_G16R16F"); break;
    case D3DFMT_A16B16G16R16F:   pstr = TEXT("D3DFMT_A16B16G16R16F"); break;
    case D3DFMT_R32F:            pstr = TEXT("D3DFMT_R32F"); break;
    case D3DFMT_G32R32F:         pstr = TEXT("D3DFMT_G32R32F"); break;
    case D3DFMT_A32B32G32R32F:   pstr = TEXT("D3DFMT_A32B32G32R32F"); break;
    case D3DFMT_CxV8U8:          pstr = TEXT("D3DFMT_CxV8U8"); break;
    default:                     pstr = TEXT("Unknown format"); break;
    }
    if( bWithPrefix || _tcsstr( pstr, TEXT("D3DFMT_") )== NULL )
        return pstr;
    else
        return pstr + lstrlen( TEXT("D3DFMT_") );
}


//-----------------------------------------------------------------------------
// Name: D3DXQuaternionUnitAxisToUnitAxis2
// Desc: Axis to axis quaternion double angle (no normalization)
//       Takes two points on unit sphere an angle THETA apart, returns
//       quaternion that represents a rotation around cross product by 2*THETA.
//-----------------------------------------------------------------------------
inline D3DXQUATERNION* WINAPI D3DXQuaternionUnitAxisToUnitAxis2
( D3DXQUATERNION *pOut, const D3DXVECTOR3 *pvFrom, const D3DXVECTOR3 *pvTo)
{
    D3DXVECTOR3 vAxis;
    D3DXVec3Cross(&vAxis, pvFrom, pvTo);    // proportional to sin(theta)
    pOut->x = vAxis.x;
    pOut->y = vAxis.y;
    pOut->z = vAxis.z;
    pOut->w = D3DXVec3Dot( pvFrom, pvTo );
    return pOut;
}




//-----------------------------------------------------------------------------
// Name: D3DXQuaternionAxisToAxis
// Desc: Axis to axis quaternion 
//       Takes two points on unit sphere an angle THETA apart, returns
//       quaternion that represents a rotation around cross product by theta.
//-----------------------------------------------------------------------------
inline D3DXQUATERNION* WINAPI D3DXQuaternionAxisToAxis
( D3DXQUATERNION *pOut, const D3DXVECTOR3 *pvFrom, const D3DXVECTOR3 *pvTo)
{
    D3DXVECTOR3 vA, vB;
    D3DXVec3Normalize(&vA, pvFrom);
    D3DXVec3Normalize(&vB, pvTo);
    D3DXVECTOR3 vHalf(vA + vB);
    D3DXVec3Normalize(&vHalf, &vHalf);
    return D3DXQuaternionUnitAxisToUnitAxis2(pOut, &vA, &vHalf);
}




//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
CD3DArcBall::CD3DArcBall()
{
    Init();
}




//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
void CD3DArcBall::Init()
{
    D3DXQuaternionIdentity( &m_qDown );
    D3DXQuaternionIdentity( &m_qNow );
    D3DXMatrixIdentity( &m_matRotation );
    D3DXMatrixIdentity( &m_matRotationDelta );
    D3DXMatrixIdentity( &m_matTranslation );
    D3DXMatrixIdentity( &m_matTranslationDelta );
    m_bDrag = FALSE;
    m_fRadiusTranslation = 1.0f;
    m_bRightHanded = FALSE;
}




//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
VOID CD3DArcBall::SetWindow( int iWidth, int iHeight, float fRadius )
{
    // Set ArcBall info
    m_iWidth  = iWidth;
    m_iHeight = iHeight;
    m_fRadius = fRadius;
}




//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
D3DXVECTOR3 CD3DArcBall::ScreenToVector( int sx, int sy )
{
    // Scale to screen
    FLOAT x   = -(sx - m_iWidth/2)  / (m_fRadius*m_iWidth/2);
    FLOAT y   =  (sy - m_iHeight/2) / (m_fRadius*m_iHeight/2);

    if( m_bRightHanded )
    {
        x = -x;
        y = -y;
    }

    FLOAT z   = 0.0f;
    FLOAT mag = x*x + y*y;

    if( mag > 1.0f )
    {
        FLOAT scale = 1.0f/sqrtf(mag);
        x *= scale;
        y *= scale;
    }
    else
        z = sqrtf( 1.0f - mag );

    // Return vector
    return D3DXVECTOR3( x, y, z );
}




//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
VOID CD3DArcBall::SetRadius( FLOAT fRadius )
{
    m_fRadiusTranslation = fRadius;
}




//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
LRESULT CD3DArcBall::HandleMouseMessages( HWND hWnd, UINT uMsg, WPARAM wParam,
                                          LPARAM lParam )
{
    UNREFERENCED_PARAMETER( hWnd );

    static int         iCurMouseX;      // Saved mouse position
    static int         iCurMouseY;
    static D3DXVECTOR3 s_vDown;         // Button down vector

    // Current mouse position
    int iMouseX = GET_X_LPARAM(lParam);
    int iMouseY = GET_Y_LPARAM(lParam);

    switch( uMsg )
    {
        case WM_RBUTTONDOWN:
        case WM_MBUTTONDOWN:
            // Store off the position of the cursor when the button is pressed
            iCurMouseX = iMouseX;
            iCurMouseY = iMouseY;
            return TRUE;

        case WM_LBUTTONDOWN:
            // Start drag mode
            m_bDrag = TRUE;
            s_vDown = ScreenToVector( iMouseX, iMouseY );
            m_qDown = m_qNow;
            return TRUE;

        case WM_LBUTTONUP:
            // End drag mode
            m_bDrag = FALSE;
            return TRUE;

        case WM_MOUSEMOVE:
            // Drag object
            if( MK_LBUTTON&wParam )
            {
                if( m_bDrag )
                {
                    // recompute m_qNow
                    D3DXVECTOR3 vCur = ScreenToVector( iMouseX, iMouseY );
                    D3DXQUATERNION qAxisToAxis;
                    D3DXQuaternionAxisToAxis(&qAxisToAxis, &s_vDown, &vCur);
                    m_qNow = m_qDown;
                    m_qNow *= qAxisToAxis;
                    D3DXMatrixRotationQuaternion(&m_matRotationDelta, &qAxisToAxis);
                }
                else
                    D3DXMatrixIdentity(&m_matRotationDelta);
                D3DXMatrixRotationQuaternion(&m_matRotation, &m_qNow);
                m_bDrag = TRUE;
            }
            else if( (MK_RBUTTON&wParam) || (MK_MBUTTON&wParam) )
            {
                // Normalize based on size of window and bounding sphere radius
                FLOAT fDeltaX = ( iCurMouseX-iMouseX ) * m_fRadiusTranslation / m_iWidth;
                FLOAT fDeltaY = ( iCurMouseY-iMouseY ) * m_fRadiusTranslation / m_iHeight;

                if( wParam & MK_RBUTTON )
                {
                    D3DXMatrixTranslation( &m_matTranslationDelta, -2*fDeltaX, 2*fDeltaY, 0.0f );
                    D3DXMatrixMultiply( &m_matTranslation, &m_matTranslation, &m_matTranslationDelta );
                }
                else  // wParam & MK_MBUTTON
                {
                    D3DXMatrixTranslation( &m_matTranslationDelta, 0.0f, 0.0f, 5*fDeltaY );
                    D3DXMatrixMultiply( &m_matTranslation, &m_matTranslation, &m_matTranslationDelta );
                }

                // Store mouse coordinate
                iCurMouseX = iMouseX;
                iCurMouseY = iMouseY;
            }
            return TRUE;
    }

    return FALSE;
}




//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
CD3DCamera::CD3DCamera()
{
    // Set attributes for the view matrix
    D3DXVECTOR3 vEyePt(0.0f,0.0f,0.0f);
    D3DXVECTOR3 vLookatPt(0.0f,0.0f,1.0f);
    D3DXVECTOR3 vUpVec(0.0f,1.0f,0.0f);
    SetViewParams( vEyePt, vLookatPt, vUpVec );

    // Set attributes for the projection matrix
    SetProjParams( D3DX_PI/4, 1.0f, 1.0f, 1000.0f );
}




//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
VOID CD3DCamera::SetViewParams( D3DXVECTOR3 &vEyePt, D3DXVECTOR3& vLookatPt,
                                D3DXVECTOR3& vUpVec )
{
    // Set attributes for the view matrix
    m_vEyePt    = vEyePt;
    m_vLookatPt = vLookatPt;
    m_vUpVec    = vUpVec;
    D3DXVECTOR3 vDir = m_vLookatPt - m_vEyePt;
    D3DXVec3Normalize( &m_vView, &vDir );
    D3DXVec3Cross( &m_vCross, &m_vView, &m_vUpVec );

    D3DXMatrixLookAtLH( &m_matView, &m_vEyePt, &m_vLookatPt, &m_vUpVec );
    D3DXMatrixInverse( &m_matBillboard, NULL, &m_matView );
    m_matBillboard._41 = 0.0f;
    m_matBillboard._42 = 0.0f;
    m_matBillboard._43 = 0.0f;
}




//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
VOID CD3DCamera::SetProjParams( FLOAT fFOV, FLOAT fAspect, FLOAT fNearPlane,
                                FLOAT fFarPlane )
{
    // Set attributes for the projection matrix
    m_fFOV        = fFOV;
    m_fAspect     = fAspect;
    m_fNearPlane  = fNearPlane;
    m_fFarPlane   = fFarPlane;

    D3DXMatrixPerspectiveFovLH( &m_matProj, fFOV, fAspect, fNearPlane, fFarPlane );
}