qafGeom.h

/* 
** Qaf Framework 1.2
** June 2006
** 
** Pedro Luchini de Moraes, Public Domain - Free Lunch Code
*/

#ifndef QAF_UTIL_GEOM_H
#define QAF_UTIL_GEOM_H

#include "qafContainer.h"
#include "qafVector2D.h"
#include "../qafDef.h"


namespace qaf {

    class Geom {
        public:
            
            static bool segmentIntersection ( float s1x1, float s1y1,
                                              float s1x2, float s1y2,
                                              float s2x1, float s2y1, 
                                              float s2x2, float s2y2,
                                              Vector2D * point = NULL );
            
            

            static bool insidePolygon ( const Vector2D & p, const Vector2D * points, int nPoints);
            
            static inline bool insidePolygon ( const Vector2D & p, const Container<Vector2D> & points ) {
                return insidePolygon( p, points.getData(), points.getCount() );
            }
            
            

            static void renderPolygon ( const Vector2D * points, int nPoints, float translateX, float translateY, unsigned long color );
            
            static inline void renderPolygon ( const Container<Vector2D> & points, float translateX, float translateY, unsigned long color ) {
                renderPolygon( points.getData(), points.getCount(), translateX, translateY, color );
            }
            
            
            static int segmentCircleIntersection ( float xCenter, float yCenter,
                                                   float radius,
                                                   float x1, float y1,
                                                   float x2, float y2,
                                                   Vector2D * pvIntPoint1 = NULL,
                                                   Vector2D * pvIntPoint2 = NULL );
            
            
            static void renderCircle ( float xCenter, float yCenter, float radius, unsigned int color );
            
            
            static inline float invSqrt ( float x ) {
                float xhalf = 0.5f*x;
                int i = *(int*)&x; // get bits for floating value
                i = 0x5f3759df - (i>>1); // gives initial guess y0
                x = *(float*)&i; // convert bits back to float
                x = x*(1.5f-xhalf*x*x); // Newton step, repeating increases accuracy
                
                return x;
            }
            
            
            static void clipPolygon ( Container<Vector2D> * poly,
                                      const Vector2D & planeP,
                                      const Vector2D & planeN );
            
    };
    
}



#endif

---