dxutmisc.cpp

游戏编程精粹6的光盘源代码

    {
        case WM_KEYDOWN:
        {
            // Map this key to a D3DUtil_CameraKeys enum and update the
            // state of m_aKeys[] by adding the KEY_WAS_DOWN_MASK|KEY_IS_DOWN_MASK mask
            // only if the key is not down
            D3DUtil_CameraKeys mappedKey = MapKey( (UINT)wParam );
            if( mappedKey != CAM_UNKNOWN )
            {
                if( FALSE == IsKeyDown(m_aKeys[mappedKey]) )
                {
                    m_aKeys[ mappedKey ] = KEY_WAS_DOWN_MASK | KEY_IS_DOWN_MASK;
                    ++m_cKeysDown;
                }
            }
            break;
        }

        case WM_KEYUP:
        {
            // Map this key to a D3DUtil_CameraKeys enum and update the
            // state of m_aKeys[] by removing the KEY_IS_DOWN_MASK mask.
            D3DUtil_CameraKeys mappedKey = MapKey( (UINT)wParam );
            if( mappedKey != CAM_UNKNOWN && (DWORD)mappedKey < 8 )
            {
                m_aKeys[ mappedKey ] &= ~KEY_IS_DOWN_MASK;
                --m_cKeysDown;
            }
            break;
        }

        case WM_RBUTTONDOWN:
        case WM_MBUTTONDOWN:
        case WM_LBUTTONDOWN:
        case WM_RBUTTONDBLCLK:
        case WM_MBUTTONDBLCLK:
        case WM_LBUTTONDBLCLK:
        {
            // Compute the drag rectangle in screen coord.
            POINT ptCursor = { (short)LOWORD(lParam), (short)HIWORD(lParam) };

            // Update member var state
            if( ( uMsg == WM_LBUTTONDOWN || uMsg == WM_LBUTTONDBLCLK ) && PtInRect( &m_rcDrag, ptCursor ) )
                { m_bMouseLButtonDown = true; m_nCurrentButtonMask |= MOUSE_LEFT_BUTTON; }
            if( ( uMsg == WM_MBUTTONDOWN || uMsg == WM_MBUTTONDBLCLK ) && PtInRect( &m_rcDrag, ptCursor ) )
                { m_bMouseMButtonDown = true; m_nCurrentButtonMask |= MOUSE_MIDDLE_BUTTON; }
            if( ( uMsg == WM_RBUTTONDOWN || uMsg == WM_RBUTTONDBLCLK ) && PtInRect( &m_rcDrag, ptCursor ) )
                { m_bMouseRButtonDown = true; m_nCurrentButtonMask |= MOUSE_RIGHT_BUTTON; }

            // Capture the mouse, so if the mouse button is 
            // released outside the window, we'll get the WM_LBUTTONUP message
            SetCapture(hWnd);
            GetCursorPos( &m_ptLastMousePosition );
            return TRUE;
        }

        case WM_RBUTTONUP: 
        case WM_MBUTTONUP: 
        case WM_LBUTTONUP:   
        {
            // Update member var state
            if( uMsg == WM_LBUTTONUP ) { m_bMouseLButtonDown = false; m_nCurrentButtonMask &= ~MOUSE_LEFT_BUTTON; }
            if( uMsg == WM_MBUTTONUP ) { m_bMouseMButtonDown = false; m_nCurrentButtonMask &= ~MOUSE_MIDDLE_BUTTON; }
            if( uMsg == WM_RBUTTONUP ) { m_bMouseRButtonDown = false; m_nCurrentButtonMask &= ~MOUSE_RIGHT_BUTTON; }

            // Release the capture if no mouse buttons down
            if( !m_bMouseLButtonDown  && 
                !m_bMouseRButtonDown &&
                !m_bMouseMButtonDown )
            {
                ReleaseCapture();
            }
            break;
        }

        case WM_MOUSEWHEEL: 
            // Update member var state
            m_nMouseWheelDelta = (short)HIWORD(wParam) / 120;
            break;
    }

    return FALSE;
}




//--------------------------------------------------------------------------------------
// Figure out the mouse delta based on mouse movement
//--------------------------------------------------------------------------------------
void CBaseCamera::UpdateMouseDelta( float fElapsedTime )
{
    UNREFERENCED_PARAMETER( fElapsedTime );

    POINT ptCurMouseDelta;
    POINT ptCurMousePos;
    
    // Get current position of mouse
    GetCursorPos( &ptCurMousePos );

    // Calc how far it's moved since last frame
    ptCurMouseDelta.x = ptCurMousePos.x - m_ptLastMousePosition.x;
    ptCurMouseDelta.y = ptCurMousePos.y - m_ptLastMousePosition.y;

    // Record current position for next time
    m_ptLastMousePosition = ptCurMousePos;

    if( m_bResetCursorAfterMove && DXUTIsActive() )
    {
        // Set position of camera to center of desktop, 
        // so it always has room to move.  This is very useful
        // if the cursor is hidden.  If this isn't done and cursor is hidden, 
        // then invisible cursor will hit the edge of the screen 
        // and the user can't tell what happened
        POINT ptCenter;
        RECT rcDesktop;
        GetWindowRect( GetDesktopWindow(), &rcDesktop );
        ptCenter.x = (rcDesktop.right - rcDesktop.left) / 2;
        ptCenter.y = (rcDesktop.bottom - rcDesktop.top) / 2;   
        SetCursorPos( ptCenter.x, ptCenter.y );
        m_ptLastMousePosition = ptCenter;
    }

    // Smooth the relative mouse data over a few frames so it isn't 
    // jerky when moving slowly at low frame rates.
    float fPercentOfNew =  1.0f / m_fFramesToSmoothMouseData;
    float fPercentOfOld =  1.0f - fPercentOfNew;
    m_vMouseDelta.x = m_vMouseDelta.x*fPercentOfOld + ptCurMouseDelta.x*fPercentOfNew;
    m_vMouseDelta.y = m_vMouseDelta.y*fPercentOfOld + ptCurMouseDelta.y*fPercentOfNew;

    m_vRotVelocity = m_vMouseDelta * m_fRotationScaler;
}




//--------------------------------------------------------------------------------------
// Figure out the velocity based on keyboard input & drag if any
//--------------------------------------------------------------------------------------
void CBaseCamera::UpdateVelocity( float fElapsedTime )
{
    D3DXMATRIX mRotDelta;
    D3DXVECTOR3 vAccel = D3DXVECTOR3(0,0,0);

    if( m_bEnablePositionMovement )
    {
        // Update acceleration vector based on keyboard state
        if( IsKeyDown(m_aKeys[CAM_MOVE_FORWARD]) )
            vAccel.z += 1.0f;
        if( IsKeyDown(m_aKeys[CAM_MOVE_BACKWARD]) )
            vAccel.z -= 1.0f;
        if( m_bEnableYAxisMovement )
        {
            if( IsKeyDown(m_aKeys[CAM_MOVE_UP]) )
                vAccel.y += 1.0f;
            if( IsKeyDown(m_aKeys[CAM_MOVE_DOWN]) )
                vAccel.y -= 1.0f;
        }
        if( IsKeyDown(m_aKeys[CAM_STRAFE_RIGHT]) )
            vAccel.x += 1.0f;
        if( IsKeyDown(m_aKeys[CAM_STRAFE_LEFT]) )
            vAccel.x -= 1.0f;
    }

    // Normalize vector so if moving 2 dirs (left & forward), 
    // the camera doesn't move faster than if moving in 1 dir
    D3DXVec3Normalize( &vAccel, &vAccel );

    // Scale the acceleration vector
    vAccel *= m_fMoveScaler;

    if( m_bMovementDrag )
    {
        // Is there any acceleration this frame?
        if( D3DXVec3LengthSq( &vAccel ) > 0 )
        {
            // If so, then this means the user has pressed a movement key\
            // so change the velocity immediately to acceleration 
            // upon keyboard input.  This isn't normal physics
            // but it will give a quick response to keyboard input
            m_vVelocity = vAccel;
            m_fDragTimer = m_fTotalDragTimeToZero;
            m_vVelocityDrag = vAccel / m_fDragTimer;
        }
        else 
        {
            // If no key being pressed, then slowly decrease velocity to 0
            if( m_fDragTimer > 0 )
            {
                // Drag until timer is <= 0
                m_vVelocity -= m_vVelocityDrag * fElapsedTime;
                m_fDragTimer -= fElapsedTime;
            }
            else
            {
                // Zero velocity
                m_vVelocity = D3DXVECTOR3(0,0,0);
            }
        }
    }
    else
    {
        // No drag, so immediately change the velocity
        m_vVelocity = vAccel;
    }
}




//--------------------------------------------------------------------------------------
// Clamps pV to lie inside m_vMinBoundary & m_vMaxBoundary
//--------------------------------------------------------------------------------------
void CBaseCamera::ConstrainToBoundary( D3DXVECTOR3* pV )
{
    // Constrain vector to a bounding box 
    pV->x = __max(pV->x, m_vMinBoundary.x);
    pV->y = __max(pV->y, m_vMinBoundary.y);
    pV->z = __max(pV->z, m_vMinBoundary.z);

    pV->x = __min(pV->x, m_vMaxBoundary.x);
    pV->y = __min(pV->y, m_vMaxBoundary.y);
    pV->z = __min(pV->z, m_vMaxBoundary.z);
}




//--------------------------------------------------------------------------------------
// Maps a windows virtual key to an enum
//--------------------------------------------------------------------------------------
D3DUtil_CameraKeys CBaseCamera::MapKey( UINT nKey )
{
    // This could be upgraded to a method that's user-definable but for 
    // simplicity, we'll use a hardcoded mapping.
    switch( nKey )
    {
        case VK_CONTROL:  return CAM_CONTROLDOWN;
        case VK_LEFT:  return CAM_STRAFE_LEFT;
        case VK_RIGHT: return CAM_STRAFE_RIGHT;
        case VK_UP:    return CAM_MOVE_FORWARD;
        case VK_DOWN:  return CAM_MOVE_BACKWARD;
        case VK_PRIOR: return CAM_MOVE_UP;        // pgup
        case VK_NEXT:  return CAM_MOVE_DOWN;      // pgdn

        case 'A':      return CAM_STRAFE_LEFT;
        case 'D':      return CAM_STRAFE_RIGHT;
        case 'W':      return CAM_MOVE_FORWARD;
        case 'S':      return CAM_MOVE_BACKWARD;
        case 'Q':      return CAM_MOVE_DOWN;
        case 'E':      return CAM_MOVE_UP;

        case VK_NUMPAD4: return CAM_STRAFE_LEFT;
        case VK_NUMPAD6: return CAM_STRAFE_RIGHT;
        case VK_NUMPAD8: return CAM_MOVE_FORWARD;
        case VK_NUMPAD2: return CAM_MOVE_BACKWARD;
        case VK_NUMPAD9: return CAM_MOVE_UP;        
        case VK_NUMPAD3: return CAM_MOVE_DOWN;      

        case VK_HOME:   return CAM_RESET;
    }

    return CAM_UNKNOWN;
}




//--------------------------------------------------------------------------------------
// Reset the camera's position back to the default
//--------------------------------------------------------------------------------------
VOID CBaseCamera::Reset()
{
    SetViewParams( &m_vDefaultEye, &m_vDefaultLookAt );
}




//--------------------------------------------------------------------------------------
// Constructor
//--------------------------------------------------------------------------------------
CFirstPersonCamera::CFirstPersonCamera() :
    m_nActiveButtonMask( 0x07 )
{
	m_bRotateWithoutButtonDown = false;
}




//--------------------------------------------------------------------------------------
// Update the view matrix based on user input & elapsed time
//--------------------------------------------------------------------------------------
VOID CFirstPersonCamera::FrameMove( FLOAT fElapsedTime )
{
    if( DXUTGetGlobalTimer()->IsStopped() )
        fElapsedTime = 1.0f / DXUTGetFPS();

    if( IsKeyDown(m_aKeys[CAM_RESET]) )
        Reset();

    // Get the mouse movement (if any) if the mouse button are down
    if( (m_nActiveButtonMask & m_nCurrentButtonMask) || m_bRotateWithoutButtonDown )
        UpdateMouseDelta( fElapsedTime );

    // Get amount of velocity based on the keyboard input and drag (if any)
    UpdateVelocity( fElapsedTime );

    // Simple euler method to calculate position delta
    D3DXVECTOR3 vPosDelta = m_vVelocity * fElapsedTime;

    // If rotating the camera 
    if( (m_nActiveButtonMask & m_nCurrentButtonMask) || m_bRotateWithoutButtonDown )
    {
        // Update the pitch & yaw angle based on mouse movement
        float fYawDelta   = m_vRotVelocity.x;
        float fPitchDelta = m_vRotVelocity.y;

        // Invert pitch if requested
        if( m_bInvertPitch )
            fPitchDelta = -fPitchDelta;

        m_fCameraPitchAngle += fPitchDelta;
        m_fCameraYawAngle   += fYawDelta;

        // Limit pitch to straight up or straight down
        m_fCameraPitchAngle = __max( -D3DX_PI/2.0f,  m_fCameraPitchAngle );
        m_fCameraPitchAngle = __min( +D3DX_PI/2.0f,  m_fCameraPitchAngle );
    }

    // Make a rotation matrix based on the camera's yaw & pitch
    D3DXMATRIX mCameraRot;
    D3DXMatrixRotationYawPitchRoll( &mCameraRot, m_fCameraYawAngle, m_fCameraPitchAngle, 0 );

    // Transform vectors based on camera's rotation matrix
    D3DXVECTOR3 vWorldUp, vWorldAhead;
    D3DXVECTOR3 vLocalUp    = D3DXVECTOR3(0,1,0);
    D3DXVECTOR3 vLocalAhead = D3DXVECTOR3(0,0,1);
    D3DXVec3TransformCoord( &vWorldUp, &vLocalUp, &mCameraRot );
    D3DXVec3TransformCoord( &vWorldAhead, &vLocalAhead, &mCameraRot );

    // Transform the position delta by the camera's rotation