/*=========================================================================

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkCamera.h,v $
  Language:  C++
  Date:      $Date: 2001/11/18 17:53:25 $
  Version:   $Revision: 1.80 $


Copyright (c) 1993-2001 Ken Martin, Will Schroeder, Bill Lorensen 
All rights reserved.

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modification, are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.

 * Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

 * Modified source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=========================================================================*/
// .NAME vtkCamera - a virtual camera for 3D rendering
// .SECTION Description
// vtkCamera is a virtual camera for 3D rendering. It provides methods
// to position and orient the view point and focal point. Convenience 
// methods for moving about the focal point also are provided. More 
// complex methods allow the manipulation of the computer graphics
// model including view up vector, clipping planes, and 
// camera perspective.
// .SECTION See Also
// vtkPerspectiveTransform

#ifndef __vtkCamera_h
#define __vtkCamera_h

#include "vtkObject.h"
#include "vtkTransform.h"
#include "vtkPerspectiveTransform.h"

class vtkRenderer;

class VTK_RENDERING_EXPORT vtkCamera : public vtkObject
{
 public:
  void PrintSelf(ostream& os, vtkIndent indent);
  vtkTypeMacro(vtkCamera,vtkObject);

  // Description:
  // Construct camera instance with its focal point at the origin, 
  // and position=(0,0,1). The view up is along the y-axis, 
  // view angle is 30 degrees, and the clipping range is (.1,1000).
  static vtkCamera *New();

  // Description:
  // Set/Get the position of the camera in world coordinates.
  // The default position is (0,0,1).
  void SetPosition(double x, double y, double z);
  void SetPosition(const double a[3]) {
    this->SetPosition(a[0], a[1], a[2]); };
  void SetPosition(const float a[3]) {
    this->SetPosition(a[0], a[1], a[2]); };
  vtkGetVector3Macro(Position,double);
  void GetPosition(float a[3]) {
    double tmp[3]; this->GetPosition(tmp); 
    a[0] = tmp[0]; a[1] = tmp[1]; a[2] = tmp[2]; };     

  // Description:
  // Set/Get the focal of the camera in world coordinates.
  // The default focal point is the origin.
  void SetFocalPoint(double x, double y, double z);
  void SetFocalPoint(const double a[3]) {
    this->SetFocalPoint(a[0], a[1], a[2]);};
  void SetFocalPoint(const float a[3]) {
    this->SetFocalPoint(a[0], a[1], a[2]);};
  vtkGetVector3Macro(FocalPoint,double);
  void GetFocalPoint(float a[3]) {
    double tmp[3]; this->GetFocalPoint(tmp); 
    a[0] = tmp[0]; a[1] = tmp[1]; a[2] = tmp[2]; }; 
  
  // Description:
  // Set/Get the view up direction for the camera.  The default
  // is (0,1,0).  
  void SetViewUp(double vx, double vy, double vz);
  void SetViewUp(const double a[3]) {
    this->SetViewUp(a[0], a[1], a[2]); }
  void SetViewUp(const float a[3]) {
    this->SetViewUp(a[0], a[1], a[2]); }
  vtkGetVector3Macro(ViewUp,double);
  void GetViewUp(float a[3]) {
    double tmp[3]; this->GetViewUp(tmp); 
    a[0] = tmp[0]; a[1] = tmp[1]; a[2] = tmp[2]; }; 

  // Description:
  // Recompute the ViewUp vector to force it to be perpendicular to
  // camera->focalpoint vector.  Unless you are going to use
  // Yaw or Azimuth on the camera, there is no need to do this.
  void OrthogonalizeViewUp();

  // Description:
  // Move the focal point so that it is the specified distance from
  // the camera position.  This distance must be positive.
  void SetDistance(double);
  vtkGetMacro(Distance,double);

  // Description:
  // Get the vector in the direction from the camera position to the
  // focal point.  This is usually the opposite of the ViewPlaneNormal,
  // the vector perpendicular to the screen, unless the view is oblique.
  vtkGetVector3Macro(DirectionOfProjection,double);
  void GetDirectionOfProjection(float a[3]) {
    double tmp[3]; this->GetDirectionOfProjection(tmp); 
    a[0] = tmp[0]; a[1] = tmp[1]; a[2] = tmp[2]; }; 

  // Description:
  // Move the position of the camera along the direction of projection. Moving
  // towards the focal point (e.g., greater than 1) is a dolly-in, moving away 
  // from the focal point (e.g., less than 1) is a dolly-out.
  void Dolly(double distance);

  // Description:
  // Set the roll angle of the camera about the direction of projection.
  void SetRoll(double angle);
  double GetRoll();

  // Description:
  // Rotate the camera about the direction of projection.
  void Roll(double angle);

  // Description:
  // Rotate the camera about the view up vector centered at the focal point.
  // Note that the view up vector is not necessarily perpendicular to the
  // direction of projection.
  void Azimuth(double angle);

  // Description:
  // Rotate the focal point about the view up vector centered at the camera's 
  // position.  Note that the view up vector is not necessarily perpendicular
  // to the direction of projection.
  void Yaw(double angle);

  // Description:
  // Rotate the camera about the cross product of the direction of projection
  // and the view up vector centered on the focal point.
  void Elevation(double angle);

  // Description:
  // Rotate the focal point about the cross product of the view up vector 
  // and the direction of projection, centered at the camera's position.
  void Pitch(double angle);

  // Description: 
  // Set/Get the value of the ParallelProjection instance variable. This
  // determines if the camera should do a perspective or parallel projection.
  void SetParallelProjection(int flag);
  vtkGetMacro(ParallelProjection,int);
  vtkBooleanMacro(ParallelProjection,int);

  // Description:
  // Set/Get the camera view angle, which is the angular height of the
  // camera view measured in degrees.  The default angle is 30 degrees.  
  // This method has no effect in parallel projection mode.
  // The formula for setting the angle up for perfect perspective viewing 
  // is: angle = 2*atan((h/2)/d) where h is the height of the RenderWindow 
  // (measured in mm by holding a ruler up to your screen) and d is the
  // distance from your eyes to the screen. 
  void SetViewAngle(double angle);
  vtkGetMacro(ViewAngle,double);

  // Description:
  // Set/Get the scaling used for a parallel projection, i.e. the height
  // of the viewport in world-coordinate distances. The default is 1.
  // Note that the "scale" parameter works as an "inverse scale" ---
  // larger numbers produce smaller images.
  // This method has no effect in perspective projection mode.
  void SetParallelScale(double scale);
  vtkGetMacro(ParallelScale,double);

  // Description:
  // In perspective mode, decrease the view angle by the specified factor.
  // In parallel mode, decrease the parallel scale by the specified factor.
  // A value greater than 1 is a zoom-in, a  value less than 1 is a zoom-out.
  void Zoom(double factor);

  // Description:
  // Set/Get the location of the near and far clipping planes along the
  // direction of projection.  Both of these values must be positive.
  // How the clipping planes are set can have a large impact on how 
  // well z-buffering works.  In particular the front clipping
  // plane can make a very big difference. Setting it to 0.01 when it
  // really could be 1.0 can have a big impact on your z-buffer resolution
  // farther away.  The default clipping range is (0.1,1000).
  void SetClippingRange(double near, double far);
  void SetClippingRange(const double a[2]) {
    this->SetClippingRange(a[0], a[1]); };
  void SetClippingRange(const float a[2]) {
    this->SetClippingRange(a[0], a[1]); };
  vtkGetVector2Macro(ClippingRange,double);
  void GetClippingRange(float a[2]) {
    double tmp[2]; this->GetClippingRange(tmp); 
    a[0] = tmp[0]; a[1] = tmp[1]; }; 

  // Description:
  // Set the distance between clipping planes.  This method adjusts the 
  // far clipping plane to be set a distance 'thickness' beyond the
  // near clipping plane.
  void SetThickness(double);
  vtkGetMacro(Thickness,double);

  // Description:
  // Set/Get the center of the window in viewport coordinates.
  // The viewport coordinate range is ([-1,+1],[-1,+1]).  This method
  // is for if you have one window which consists of several viewports,
  // or if you have several screens which you want to act together as
  // one large screen.
  void SetWindowCenter(double x, double y);
  vtkGetVector2Macro(WindowCenter,double);

  // Description:
  // Get/Set the oblique viewing angles.  The first angle, alpha, is the
  // angle (measured from the horizontal) that rays along the direction
  // of projection will follow once projected onto the 2D screen.  
  // The second angle, beta, is the angle between the view plane and
  // the direction of projection.  This creates a shear transform
  // x' = x + dz*cos(alpha)/tan(beta), y' = dz*sin(alpha)/tan(beta)
  // where dz is the distance of the point from the focal plane.
  // The angles are (45,90) by default.  Oblique projections 
  // commonly use (30,63.435).
  void SetObliqueAngles(double alpha, double beta);

  // Description:
  // Get the ViewPlaneNormal.  This vector will point opposite to
  // the direction of projection, unless you have created an sheared output
  // view using SetViewShear/SetObliqueAngles.
  vtkGetVector3Macro(ViewPlaneNormal,double);
  void GetViewPlaneNormal(float a[3]) {
    double tmp[3]; this->GetViewPlaneNormal(tmp); 
    a[0] = tmp[0]; a[1] = tmp[1]; a[2] = tmp[2]; }; 


  // Description:
  // Set/get the shear transform of the viewing frustum.  Parameters are
  // dx/dz, dy/dz, and center.  center is a factor that describes where
  // to shear around. The distance dshear from the camera where
  // no shear occurs is given by (dshear = center * FocalDistance).
  void SetViewShear(double dxdz, double dydz, double center);
  void SetViewShear(double d[3]);
  vtkGetVector3Macro(ViewShear, double);

  // Description:
  // Set/Get the separation between eyes (in degrees). This is used
  // when generating stereo images.
  vtkSetMacro(EyeAngle,double);
  vtkGetMacro(EyeAngle,double);

  // Description:
  // Set the size of the cameras lens in world coordinates. This is only 
  // used when the renderer is doing focal depth rendering. When that is 
  // being done the size of the focal disk will effect how significant the
  // depth effects will be.
  vtkSetMacro(FocalDisk,double);
  vtkGetMacro(FocalDisk,double);

  // Description:
  // Return the matrix of the view transform.
  vtkMatrix4x4 *GetViewTransformMatrix() { 
    return this->ViewTransform->GetMatrix(); };
  
  // Description:
  // Return the perspective transform matrix, which converts from camera
  // coordinates to viewport coordinates.  The 'aspect' is the
  // width/height for the viewport, and the nearz and farz are the
  // Z-buffer values that map to the near and far clipping planes.
  // The viewport coordinates are in the range ([-1,+1],[-1,+1],[nearz,farz]).
  vtkMatrix4x4 *GetPerspectiveTransformMatrix(double aspect,
                                              double nearz, 
                                              double farz);

  // Description:
  // Return the concatenation of the ViewTransform and the 
  // PerspectiveTransform.  This transform will convert world
  // coordinates to viewport coordinates.  The 'aspect' is the
  // width/height for the viewport, and the nearz and farz are the
  // Z-buffer values that map to the near and far clipping planes.
  // The viewport coordinates are in the range ([-1,+1],[-1,+1],[nearz,farz]).
  vtkMatrix4x4 *GetCompositePerspectiveTransformMatrix(double aspect, 
                                                       double nearz, 
                                                       double farz);

  // Description:
  // This method causes the camera to set up whatever is required for
  // viewing the scene. This is actually handled by an subclass of
  // vtkCamera, which is created through New()
  virtual void Render(vtkRenderer *) {};

  // Description:
  // Return the MTime that concerns recomputing the view rays of the camera.
  unsigned long GetViewingRaysMTime();

  // Description:
  // Mark that something has changed which requires the view rays
  // to be recomputed.
  void ViewingRaysModified();

  // Description:
  // Get the plane equations that bound the view frustum.
  // The plane normals point inward. The planes array contains six
  // plane equations of the form (Ax+By+Cz+D=0), the first four
  // values are (A,B,C,D) which repeats for each of the planes.
  // The aspect of the viewport is needed to correctly compute the planes
  void GetFrustumPlanes(float aspect, float planes[24]);

  // Description:
  // Get the orientation of the camera.
  float *GetOrientation() { 
    return this->ViewTransform->GetOrientation(); };
  float *GetOrientationWXYZ() { 
    return this->ViewTransform->GetOrientationWXYZ(); };

  // Description:
  // These methods have been deprecated.  The view plane normal is 
  // automatically set from the DirectionOfProjection according to
  // the ViewShear.
  void SetViewPlaneNormal(double x, double y, double z);
  void SetViewPlaneNormal(const double a[3]) {
    this->SetViewPlaneNormal(a[0], a[1], a[2]); };
  void SetViewPlaneNormal(const float a[3]) {
    this->SetViewPlaneNormal(a[0], a[1], a[2]); };

  // Description:
  // This method is called automatically whenever necessary, it
  // should never be used outside of vtkCamera.cxx.  
  void ComputeViewPlaneNormal();

  // Description:
  // Returns a transformation matrix for a coordinate frame attached to
  // the camera, where the camera is located at (0, 0, 1) looking at the
  // focal point at (0, 0, 0), with up being (0, 1, 0).
  vtkMatrix4x4 *GetCameraLightTransformMatrix();
  
  // Description:
  // Update the viewport
  virtual void UpdateViewport(vtkRenderer *vtkNotUsed(ren)) {}
  
#ifndef VTK_REMOVE_LEGACY_CODE
  // Description:
  // For legacy compatibility. Do not use.
  vtkMatrix4x4 &GetViewTransform()
    {VTK_LEGACY_METHOD(GetViewTransformMatrix,"3.2"); return *this->GetViewTransformMatrix();}
  vtkMatrix4x4 &GetPerspectiveTransform(double aspect,double nearz,double farz) 
    {VTK_LEGACY_METHOD(GetPerspectiveTransformMatrix,"3.2"); return *this->GetPerspectiveTransformMatrix(aspect, nearz, farz);}
  vtkMatrix4x4 &GetCompositePerspectiveTransform(double aspect, double nearz, double farz) 
    {VTK_LEGACY_METHOD(GetCompositePerspectiveTransformMatrix,"3.2"); return *this->GetCompositePerspectiveTransformMatrix(aspect,nearz,farz);}
#endif

  vtkTransform *GetViewTransformObject() {return this->ViewTransform;};
  
protected:
  vtkCamera();
  ~vtkCamera();

  // Description:
  // These methods should only be used within vtkCamera.cxx.
  void ComputeDistance();
  void ComputeViewTransform();
  void ComputePerspectiveTransform(double aspect, double nearz, double farz);
  void ComputeCompositePerspectiveTransform(double aspect, 
                                            double nearz, double farz);
  void ComputeCameraLightTransform();

  double WindowCenter[2];
  double ObliqueAngles[2];
  double FocalPoint[3];
  double Position[3];
  double ViewUp[3];
  double ViewAngle;
  double ClippingRange[2];
  double EyeAngle;
  int    ParallelProjection;
  double ParallelScale;
  int    Stereo;
  int    LeftEye;
  double Thickness;
  double Distance;
  double DirectionOfProjection[3];
  double ViewPlaneNormal[3];
  double ViewShear[3];

  vtkTransform *ViewTransform;
  vtkPerspectiveTransform *PerspectiveTransform;
  vtkPerspectiveTransform *Transform;
  vtkTransform *CameraLightTransform;

  double FocalDisk;

  // ViewingRaysMtime keeps track of camera modifications which will 
  // change the calculation of viewing rays for the camera before it is 
  // transformed to the camera's location and orientation. 
  vtkTimeStamp ViewingRaysMTime;
private:
  vtkCamera(const vtkCamera&);  // Not implemented.
  void operator=(const vtkCamera&);  // Not implemented.
};

#endif

