112 lines
1.8 KiB
C++
Executable File
112 lines
1.8 KiB
C++
Executable File
/*
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(c) 2013 Nicolaus Anderson
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*/
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#include <irrlicht.h>
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#ifndef _CIRCLE2D_
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#define _CIRCLE2D_
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namespace irr
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{
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namespace core
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{
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//! Class circle 2D
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/*
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A 2D circle.
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*/
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template<class T>
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class circle2d
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{
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public:
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vector2d<T> center;
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T radius;
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circle2d()
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: radius( (T)0 )
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{}
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circle2d( T x, T y, T r )
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: center( vector2d<T>(x,y) )
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, radius( r )
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{}
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circle2d( vector2d<T> origin, T r )
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: center( origin )
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, radius( r )
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{}
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//! Set
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void set( T x, T y, T r )
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{
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center = vector2d<T>(x,y);
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radius = r;
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}
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//! Set
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void set( vector2d<T> origin, T r )
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{
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center = origin;
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radius = r;
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}
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//! Top point
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/* Returns a vector that gives the top-most point on the circle. */
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vector2d<T> topPoint()
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{
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return vector2d<T>( center.X, center.Y + radius);
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}
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//! Get area
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T getArea()
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{
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return PI * radius * radius;
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}
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//! Circumference
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inline T getCircumference()
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{
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return 2 * PI * radius;
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}
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//! Point inside?
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bool isPointInside( vector2d<T> point )
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{
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return ( point - center ).getLengthSQ() <= radius * radius;
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}
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//! Get horizon
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/* Returns the horizontal secant line of the circle at the given
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distance from the top.
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The line goes from the left side of the circle to the right side. */
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line2d<T> getHorizon( T distDown )
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{
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line2d<T> ret;
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ret.start.Y = center.Y + radius - distDown;
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ret.end.Y = ret.start.Y;
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ret.end.X = (T) squareroot( (irr::f64)
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( radius * radius ) - ret.start.Y
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);
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ret.start.X = - ret.end.X; // get the negative of the sqrt
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// correct origin offset
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ret.start.X += center.X;
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ret.end.X += center.X;
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return ret;
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}
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};
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typedef circle2d<irr::s32> circle2di;
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typedef circle2d<irr::f32> circle2df;
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} // end namespace core
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} // end namespace irr
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#endif // #ifndef _CIRCLE2D_
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