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Arc Class Reference

#include <GeometricalObjects.h>

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Public Member Functions

 Arc ()
 Arc (const Vector2D &c, const double r1, const double r2, const double a1, const double a2)
 ~Arc ()
double get_distance (const Vector2D &pos, const Vector2D &dir, const double size)
bool within_distance (const Vector2D &pos, const double size)
Vector2D get_normal (const Vector2D &pos)
void draw_shape (bool erase)
double get_inner_radius ()
double get_outer_radius ()
Vector2D get_center ()
double get_start_angle ()
double get_end_angle ()

Protected Attributes

Vector2D center
double inner_radius
double outer_radius
double start_angle
double end_angle
Vector2D last_drawn_center

Private Member Functions

bool within_angle (const double a)

Private Attributes

double mid_radiussqr

Constructor & Destructor Documentation

Arc::Arc (   ) 
 

Definition at line 276 of file GeometricalObjects.cc.

References center, end_angle, infinity, inner_radius, last_drawn_center, mid_radiussqr, outer_radius, and start_angle.

00277 {
00278   center = Vector2D(0.0, 0.0);
00279   inner_radius = outer_radius = mid_radiussqr = 0.0;
00280   start_angle = -M_PI; end_angle = M_PI;
00281   last_drawn_center = Vector2D(-infinity,-infinity);
00282   //  last_drawn_radius = 0.0;
00283 }

Arc::Arc (  const Vector2D &  c,
const double  r1,
const double  r2,
const double  a1,
const double  a2
) 
 

Definition at line 285 of file GeometricalObjects.cc.

References center, end_angle, inner_radius, last_drawn_center, mid_radiussqr, outer_radius, and start_angle.

00287 {
00288   last_drawn_center = center = c;
00289   inner_radius = r1;
00290   outer_radius = r2;
00291   mid_radiussqr = 0.25 * (r1 + r2) * (r1 + r2);
00292   start_angle = a1;
00293   end_angle = a2;
00294 }

Arc::~Arc (   )  [inline]
 

Definition at line 137 of file GeometricalObjects.h.

00137 {}

Member Function Documentation

void Arc::draw_shape (  bool  erase  )  [virtual]
 

Implements Shape.

Definition at line 384 of file GeometricalObjects.cc.

References center, ArenaWindow::draw_arc(), end_angle, Gui::get_arenawindow_p(), Gui::get_bg_gdk_colour_p(), inner_radius, last_drawn_center, outer_radius, start_angle, and the_gui.

00385 {
00386 
00387   if( erase )
00388     the_gui.get_arenawindow_p()->draw_arc( last_drawn_center,
00389                                            inner_radius, outer_radius,
00390                                            start_angle, end_angle,
00391                                            *(the_gui.get_bg_gdk_colour_p()) );
00392   last_drawn_center = center;
00393 
00394   
00395   the_gui.get_arenawindow_p()->draw_arc( center, 
00396                                          inner_radius, outer_radius,
00397                                          start_angle, end_angle,
00398                                          gdk_colour );
00399 }

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Vector2D Arc::get_center (   )  [inline]
 

Definition at line 149 of file GeometricalObjects.h.

00149 { return center; }

double Arc::get_distance (  const Vector2D &  pos,
const Vector2D &  dir,
const double  size
)  [inline, virtual]
 

Implements Shape.

Definition at line 305 of file GeometricalObjects.cc.

References center, dot(), lengthsqr(), max, vec2angle(), and within_angle().

00306 {
00307   Vector2D d = center - pos;
00308   double speedsqr = lengthsqr(vel);
00309   if( speedsqr == 0.0 ) return infinity;
00310 
00311   double c, r, t;
00312   double dt = dot(vel, d);
00313 
00314   if( lengthsqr( d ) > mid_radiussqr )
00315     {
00316       // Outside circle
00317   
00318       r = size + outer_radius;
00319       c = dt*dt + speedsqr * (r*r - lengthsqr(d));
00320       if( c < 0.0 || dt <= 0.0) return infinity;
00321       t = max( (dt - sqrt(c))/speedsqr, 0);
00322 
00323       if( within_angle( vec2angle( vel * t - d ) ) )
00324         return t;
00325 
00326       // Did hit the outer circle, but not within the angles.
00327       // Can still hit inner circle.
00328     }
00329 
00330   
00331 
00332   // Test inner circle
00333       
00334   r = size - inner_radius;
00335   
00336   c = dt*dt + speedsqr*( r*r - lengthsqr(d) );
00337   if( c < 0.0 ) return infinity;  // Can happen if object outside circle
00338   
00339   t =  max( (dt + sqrt(c))/speedsqr, 0 );
00340   
00341   if( !within_angle( vec2angle( vel * t - d  ) ) )
00342     return infinity;
00343 
00344 
00345   return t;
00346 }

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double Arc::get_end_angle (   )  [inline]
 

Definition at line 152 of file GeometricalObjects.h.

00152 { return end_angle; }

double Arc::get_inner_radius (   )  [inline]
 

Definition at line 147 of file GeometricalObjects.h.

00147 { return inner_radius; }

Vector2D Arc::get_normal (  const Vector2D &  pos  )  [virtual]
 

Implements Shape.

Definition at line 371 of file GeometricalObjects.cc.

References center, lengthsqr(), and unit().

00372 {
00373   Vector2D d = center - pos;
00374 
00375   if( lengthsqr( d ) < mid_radiussqr )
00376     return unit( d );
00377   else
00378     return unit( -d );
00379 }

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double Arc::get_outer_radius (   )  [inline]
 

Definition at line 148 of file GeometricalObjects.h.

00148 { return outer_radius; }

double Arc::get_start_angle (   )  [inline]
 

Definition at line 151 of file GeometricalObjects.h.

00151 { return start_angle; }

bool Arc::within_angle (  const double  a  )  [private]
 

Definition at line 362 of file GeometricalObjects.cc.

References start_angle.

Referenced by get_distance(), and within_distance().

00363 {
00364   if( start_angle <= end_angle )
00365     return ( a >= start_angle && a <= end_angle );
00366   else
00367     return ( a >= start_angle || a <= end_angle );
00368 }

bool Arc::within_distance (  const Vector2D &  pos,
const double  size
)  [virtual]
 

Implements Shape.

Definition at line 349 of file GeometricalObjects.cc.

References lengthsqr(), vec2angle(), and within_angle().

00350 {
00351   Vector2D d = pos - center;
00352   double l = lengthsqr( d );
00353 
00354   return( l <= (size + outer_radius)*(size + outer_radius) &&
00355           ( l >= (size - inner_radius)*(size - inner_radius) || size >= inner_radius ) &&
00356           within_angle( vec2angle( d ) ) );
00357 }

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Field Documentation

Vector2D Arc::center [protected]
 

Definition at line 156 of file GeometricalObjects.h.

Referenced by Arc(), draw_shape(), get_distance(), and get_normal().

double Arc::end_angle [protected]
 

Definition at line 162 of file GeometricalObjects.h.

Referenced by Arc(), and draw_shape().

double Arc::inner_radius [protected]
 

Definition at line 157 of file GeometricalObjects.h.

Referenced by Arc(), and draw_shape().

Vector2D Arc::last_drawn_center [protected]
 

Definition at line 164 of file GeometricalObjects.h.

Referenced by Arc(), and draw_shape().

double Arc::mid_radiussqr [private]
 

Definition at line 170 of file GeometricalObjects.h.

Referenced by Arc().

double Arc::outer_radius [protected]
 

Definition at line 158 of file GeometricalObjects.h.

Referenced by Arc(), and draw_shape().

double Arc::start_angle [protected]
 

Definition at line 161 of file GeometricalObjects.h.

Referenced by Arc(), draw_shape(), and within_angle().

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