143 lines
4.2 KiB
C++
143 lines
4.2 KiB
C++
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#ifndef __WINDING2D_H__
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#define __WINDING2D_H__
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/*
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===============================================================================
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A 2D winding is an arbitrary convex 2D polygon defined by an array of points.
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===============================================================================
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*/
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#define MAX_POINTS_ON_WINDING_2D 16
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class idWinding2D {
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public:
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idWinding2D( void );
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idWinding2D & operator=( const idWinding2D &winding );
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const idVec2 & operator[]( const int index ) const;
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idVec2 & operator[]( const int index );
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void Clear( void );
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void AddPoint( const idVec2 &point );
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int GetNumPoints( void ) const;
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void Expand( const float d );
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void ExpandForAxialBox( const idVec2 bounds[2] );
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// splits the winding into a front and back winding, the winding itself stays unchanged
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// returns a SIDE_?
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int Split( const idVec3 &plane, const float epsilon, idWinding2D **front, idWinding2D **back ) const;
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// cuts off the part at the back side of the plane, returns true if some part was at the front
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// if there is nothing at the front the number of points is set to zero
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bool ClipInPlace( const idVec3 &plane, const float epsilon = ON_EPSILON, const bool keepOn = false );
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idWinding2D * Copy( void ) const;
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idWinding2D * Reverse( void ) const;
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float GetArea( void ) const;
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idVec2 GetCenter( void ) const;
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float GetRadius( const idVec2 ¢er ) const;
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void GetBounds( idVec2 bounds[2] ) const;
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bool IsTiny( void ) const;
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bool IsHuge( void ) const; // base winding for a plane is typically huge
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void Print( void ) const;
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float PlaneDistance( const idVec3 &plane ) const;
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int PlaneSide( const idVec3 &plane, const float epsilon = ON_EPSILON ) const;
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bool PointInside( const idVec2 &point, const float epsilon ) const;
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bool LineIntersection( const idVec2 &start, const idVec2 &end ) const;
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bool RayIntersection( const idVec2 &start, const idVec2 &dir, float &scale1, float &scale2, int *edgeNums = NULL ) const;
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static idVec3 Plane2DFromPoints( const idVec2 &start, const idVec2 &end, const bool normalize = false );
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static idVec3 Plane2DFromVecs( const idVec2 &start, const idVec2 &dir, const bool normalize = false );
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static bool Plane2DIntersection( const idVec3 &plane1, const idVec3 &plane2, idVec2 &point );
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private:
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int numPoints;
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idVec2 p[MAX_POINTS_ON_WINDING_2D];
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};
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ID_INLINE idWinding2D::idWinding2D( void ) {
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numPoints = 0;
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}
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ID_INLINE idWinding2D &idWinding2D::operator=( const idWinding2D &winding ) {
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int i;
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for ( i = 0; i < winding.numPoints; i++ ) {
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p[i] = winding.p[i];
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}
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numPoints = winding.numPoints;
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return *this;
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}
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ID_INLINE const idVec2 &idWinding2D::operator[]( const int index ) const {
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return p[ index ];
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}
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ID_INLINE idVec2 &idWinding2D::operator[]( const int index ) {
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return p[ index ];
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}
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ID_INLINE void idWinding2D::Clear( void ) {
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numPoints = 0;
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}
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ID_INLINE void idWinding2D::AddPoint( const idVec2 &point ) {
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p[numPoints++] = point;
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}
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ID_INLINE int idWinding2D::GetNumPoints( void ) const {
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return numPoints;
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}
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ID_INLINE idVec3 idWinding2D::Plane2DFromPoints( const idVec2 &start, const idVec2 &end, const bool normalize ) {
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idVec3 plane;
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plane.x = start.y - end.y;
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plane.y = end.x - start.x;
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if ( normalize ) {
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plane.ToVec2().Normalize();
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}
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plane.z = - ( start.x * plane.x + start.y * plane.y );
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return plane;
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}
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ID_INLINE idVec3 idWinding2D::Plane2DFromVecs( const idVec2 &start, const idVec2 &dir, const bool normalize ) {
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idVec3 plane;
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plane.x = -dir.y;
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plane.y = dir.x;
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if ( normalize ) {
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plane.ToVec2().Normalize();
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}
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plane.z = - ( start.x * plane.x + start.y * plane.y );
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return plane;
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}
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ID_INLINE bool idWinding2D::Plane2DIntersection( const idVec3 &plane1, const idVec3 &plane2, idVec2 &point ) {
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float n00, n01, n11, det, invDet, f0, f1;
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n00 = plane1.x * plane1.x + plane1.y * plane1.y;
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n01 = plane1.x * plane2.x + plane1.y * plane2.y;
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n11 = plane2.x * plane2.x + plane2.y * plane2.y;
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det = n00 * n11 - n01 * n01;
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if ( idMath::Fabs(det) < 1e-6f ) {
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return false;
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}
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invDet = 1.0f / det;
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f0 = ( n01 * plane2.z - n11 * plane1.z ) * invDet;
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f1 = ( n01 * plane1.z - n00 * plane2.z ) * invDet;
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point.x = f0 * plane1.x + f1 * plane2.x;
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point.y = f0 * plane1.y + f1 * plane2.y;
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return true;
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}
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#endif /* !__WINDING2D_H__ */
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