1 2//---------------------------------------------------------------------------- 3// Anti-Grain Geometry - Version 2.3 4// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com) 5// 6// Permission to copy, use, modify, sell and distribute this software 7// is granted provided this copyright notice appears in all copies. 8// This software is provided "as is" without express or implied 9// warranty, and with no claim as to its suitability for any purpose. 10// 11//---------------------------------------------------------------------------- 12// Contact: mcseem@antigrain.com 13// mcseemagg@yahoo.com 14// http://www.antigrain.com 15//---------------------------------------------------------------------------- 16// Bessel function (besj) was adapted for use in AGG library by Andy Wilk 17// Contact: castor.vulgaris@gmail.com 18//---------------------------------------------------------------------------- 19#ifndef AGG_MATH_INCLUDED 20#define AGG_MATH_INCLUDED 21#include "agg_basics.h" 22namespace agg 23{ 24const float intersection_epsilon = 1.0e-30f; 25AGG_INLINE float calc_point_location(float x1, float y1, 26 float x2, float y2, 27 float x, float y) 28{ 29 return ((x - x2) * (y2 - y1)) - ((y - y2) * (x2 - x1)); 30} 31AGG_INLINE float calc_distance(float x1, float y1, float x2, float y2) 32{ 33 float dx = x2 - x1; 34 float dy = y2 - y1; 35 return FXSYS_sqrt2(dx, dy); 36} 37AGG_INLINE float calc_line_point_distance(float x1, float y1, 38 float x2, float y2, 39 float x, float y) 40{ 41 float dx = x2 - x1; 42 float dy = y2 - y1; 43 float d = FXSYS_sqrt2(dx, dy); 44 if(d < intersection_epsilon) { 45 return calc_distance(x1, y1, x, y); 46 } 47 return ((x - x2) * dy / d) - ((y - y2) * dx / d); 48} 49AGG_INLINE bool calc_intersection(float ax, float ay, float bx, float by, 50 float cx, float cy, float dx, float dy, 51 float* x, float* y) 52{ 53 float num = ((ay - cy) * (dx - cx)) - ((ax - cx) * (dy - cy)); 54 float den = ((bx - ax) * (dy - cy)) - ((by - ay) * (dx - cx)); 55 if (fabs(den) < intersection_epsilon) { 56 return false; 57 } 58 *x = ax + ((bx - ax) * num / den); 59 *y = ay + ((by - ay) * num / den); 60 return true; 61} 62} 63#endif 64