Trackball Class Reference

#include <trackball.h>

Public Types
enum	Mode { Around , Local }

Public Member Functions
	Trackball ()
void	start (Mode m=Around)
void	setCamera (Camera *pCam)
void	track (const Eigen::Vector2i &newPoint2D)

Protected Member Functions
bool	mapToSphere (const Eigen::Vector2i &p2, Eigen::Vector3f &v3)

Protected Attributes
Camera *	mpCamera
Eigen::Vector3f	mLastPoint3D
Mode	mMode
bool	mLastPointOk

Member Enumeration Documentation

Mode

enum Trackball::Mode

Enumerator
Around
Local

{ Around, Local };

Constructor & Destructor Documentation

Trackball()

Trackball::Trackball ( )

inline

: mpCamera(0) {}

Member Function Documentation

mapToSphere()

bool Trackball::mapToSphere ( const Eigen::Vector2i &  p2, Eigen::Vector3f &  v3  )

protected

                                                            {
  if ((p2.x() >= 0) && (p2.x() <= int(mpCamera->vpWidth())) && (p2.y() >= 0) && (p2.y() <= int(mpCamera->vpHeight()))) {
    double x = (double)(p2.x() - 0.5 * mpCamera->vpWidth()) / (double)mpCamera->vpWidth();
    double y = (double)(0.5 * mpCamera->vpHeight() - p2.y()) / (double)mpCamera->vpHeight();
    double sinx = sin(M_PI * x * 0.5);
    double siny = sin(M_PI * y * 0.5);
    double sinx2siny2 = sinx * sinx + siny * siny;
 
    v3.x() = sinx;
    v3.y() = siny;
    v3.z() = sinx2siny2 < 1.0 ? sqrt(1.0 - sinx2siny2) : 0.0;
 
    return true;
  } else
    return false;
}

References M_PI, sin(), sqrt(), plotDoE::x, and y.

setCamera()

void Trackball::setCamera ( Camera *  pCam )

inline

{ mpCamera = pCam; }

References mpCamera.

start()

void Trackball::start ( Mode  m = Around )

inline

                              {
    mMode = m;
    mLastPointOk = false;
  }

References m, mLastPointOk, and mMode.

track()

void Trackball::track

(

const Eigen::Vector2i &

newPoint2D

)

                                             {
  if (mpCamera == 0) return;
  Vector3f newPoint3D;
  bool newPointOk = mapToSphere(point2D, newPoint3D);
 
  if (mLastPointOk && newPointOk) {
    Vector3f axis = mLastPoint3D.cross(newPoint3D).normalized();
    float cos_angle = mLastPoint3D.dot(newPoint3D);
    if (std::abs(cos_angle) < 1.0) {
      float angle = 2. * acos(cos_angle);
      if (mMode == Around)
        mpCamera->rotateAroundTarget(Quaternionf(AngleAxisf(angle, axis)));
      else
        mpCamera->localRotate(Quaternionf(AngleAxisf(-angle, axis)));
    }
  }
 
  mLastPoint3D = newPoint3D;
  mLastPointOk = newPointOk;
}

References abs(), acos(), and Jeffery_Solution::angle().

Member Data Documentation

mLastPoint3D

Eigen::Vector3f Trackball::mLastPoint3D

protected

mLastPointOk

bool Trackball::mLastPointOk

protected

Referenced by start().

mMode

Mode Trackball::mMode

protected

Referenced by start().

mpCamera

Camera* Trackball::mpCamera

protected

Referenced by setCamera().

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The documentation for this class was generated from the following files:

• trackball.h
• trackball.cpp