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437 lines
14 KiB
437 lines
14 KiB
//---------------------------------------------------------------------------- |
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// Anti-Grain Geometry - Version 2.4 |
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// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com) |
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// |
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// Permission to copy, use, modify, sell and distribute this software |
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// is granted provided this copyright notice appears in all copies. |
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// This software is provided "as is" without express or implied |
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// warranty, and with no claim as to its suitability for any purpose. |
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// |
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//---------------------------------------------------------------------------- |
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// Contact: mcseem@antigrain.com |
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// mcseemagg@yahoo.com |
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// http://www.antigrain.com |
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//---------------------------------------------------------------------------- |
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// Bessel function (besj) was adapted for use in AGG library by Andy Wilk |
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// Contact: castor.vulgaris@gmail.com |
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//---------------------------------------------------------------------------- |
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#ifndef AGG_MATH_INCLUDED |
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#define AGG_MATH_INCLUDED |
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#include <cmath> |
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#include "agg_basics.h" |
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namespace agg |
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{ |
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//------------------------------------------------------vertex_dist_epsilon |
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// Coinciding points maximal distance (Epsilon) |
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const double vertex_dist_epsilon = 1e-14; |
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//-----------------------------------------------------intersection_epsilon |
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// See calc_intersection |
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const double intersection_epsilon = 1.0e-30; |
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//------------------------------------------------------------cross_product |
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AGG_INLINE double cross_product(double x1, double y1, |
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double x2, double y2, |
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double x, double y) |
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{ |
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return (x - x2) * (y2 - y1) - (y - y2) * (x2 - x1); |
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} |
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//--------------------------------------------------------point_in_triangle |
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AGG_INLINE bool point_in_triangle(double x1, double y1, |
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double x2, double y2, |
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double x3, double y3, |
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double x, double y) |
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{ |
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bool cp1 = cross_product(x1, y1, x2, y2, x, y) < 0.0; |
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bool cp2 = cross_product(x2, y2, x3, y3, x, y) < 0.0; |
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bool cp3 = cross_product(x3, y3, x1, y1, x, y) < 0.0; |
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return cp1 == cp2 && cp2 == cp3 && cp3 == cp1; |
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} |
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//-----------------------------------------------------------calc_distance |
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AGG_INLINE double calc_distance(double x1, double y1, double x2, double y2) |
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{ |
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double dx = x2-x1; |
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double dy = y2-y1; |
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return std::sqrt(dx * dx + dy * dy); |
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} |
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//--------------------------------------------------------calc_sq_distance |
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AGG_INLINE double calc_sq_distance(double x1, double y1, double x2, double y2) |
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{ |
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double dx = x2-x1; |
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double dy = y2-y1; |
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return dx * dx + dy * dy; |
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} |
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//------------------------------------------------calc_line_point_distance |
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AGG_INLINE double calc_line_point_distance(double x1, double y1, |
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double x2, double y2, |
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double x, double y) |
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{ |
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double dx = x2-x1; |
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double dy = y2-y1; |
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double d = std::sqrt(dx * dx + dy * dy); |
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if(d < vertex_dist_epsilon) |
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{ |
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return calc_distance(x1, y1, x, y); |
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} |
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return ((x - x2) * dy - (y - y2) * dx) / d; |
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} |
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//-------------------------------------------------------calc_line_point_u |
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AGG_INLINE double calc_segment_point_u(double x1, double y1, |
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double x2, double y2, |
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double x, double y) |
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{ |
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double dx = x2 - x1; |
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double dy = y2 - y1; |
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if(dx == 0 && dy == 0) |
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{ |
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return 0; |
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} |
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double pdx = x - x1; |
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double pdy = y - y1; |
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return (pdx * dx + pdy * dy) / (dx * dx + dy * dy); |
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} |
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//---------------------------------------------calc_line_point_sq_distance |
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AGG_INLINE double calc_segment_point_sq_distance(double x1, double y1, |
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double x2, double y2, |
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double x, double y, |
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double u) |
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{ |
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if(u <= 0) |
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{ |
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return calc_sq_distance(x, y, x1, y1); |
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} |
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else |
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if(u >= 1) |
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{ |
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return calc_sq_distance(x, y, x2, y2); |
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} |
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return calc_sq_distance(x, y, x1 + u * (x2 - x1), y1 + u * (y2 - y1)); |
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} |
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//---------------------------------------------calc_line_point_sq_distance |
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AGG_INLINE double calc_segment_point_sq_distance(double x1, double y1, |
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double x2, double y2, |
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double x, double y) |
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{ |
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return |
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calc_segment_point_sq_distance( |
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x1, y1, x2, y2, x, y, |
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calc_segment_point_u(x1, y1, x2, y2, x, y)); |
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} |
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//-------------------------------------------------------calc_intersection |
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AGG_INLINE bool calc_intersection(double ax, double ay, double bx, double by, |
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double cx, double cy, double dx, double dy, |
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double* x, double* y) |
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{ |
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double num = (ay-cy) * (dx-cx) - (ax-cx) * (dy-cy); |
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double den = (bx-ax) * (dy-cy) - (by-ay) * (dx-cx); |
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if(std::fabs(den) < intersection_epsilon) return false; |
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double r = num / den; |
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*x = ax + r * (bx-ax); |
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*y = ay + r * (by-ay); |
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return true; |
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} |
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//-----------------------------------------------------intersection_exists |
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AGG_INLINE bool intersection_exists(double x1, double y1, double x2, double y2, |
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double x3, double y3, double x4, double y4) |
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{ |
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// It's less expensive but you can't control the |
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// boundary conditions: Less or LessEqual |
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double dx1 = x2 - x1; |
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double dy1 = y2 - y1; |
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double dx2 = x4 - x3; |
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double dy2 = y4 - y3; |
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return ((x3 - x2) * dy1 - (y3 - y2) * dx1 < 0.0) != |
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((x4 - x2) * dy1 - (y4 - y2) * dx1 < 0.0) && |
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((x1 - x4) * dy2 - (y1 - y4) * dx2 < 0.0) != |
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((x2 - x4) * dy2 - (y2 - y4) * dx2 < 0.0); |
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// It's is more expensive but more flexible |
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// in terms of boundary conditions. |
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//-------------------- |
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//double den = (x2-x1) * (y4-y3) - (y2-y1) * (x4-x3); |
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//if(fabs(den) < intersection_epsilon) return false; |
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//double nom1 = (x4-x3) * (y1-y3) - (y4-y3) * (x1-x3); |
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//double nom2 = (x2-x1) * (y1-y3) - (y2-y1) * (x1-x3); |
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//double ua = nom1 / den; |
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//double ub = nom2 / den; |
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//return ua >= 0.0 && ua <= 1.0 && ub >= 0.0 && ub <= 1.0; |
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} |
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//--------------------------------------------------------calc_orthogonal |
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AGG_INLINE void calc_orthogonal(double thickness, |
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double x1, double y1, |
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double x2, double y2, |
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double* x, double* y) |
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{ |
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double dx = x2 - x1; |
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double dy = y2 - y1; |
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double d = std::sqrt(dx*dx + dy*dy); |
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*x = thickness * dy / d; |
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*y = -thickness * dx / d; |
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} |
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//--------------------------------------------------------dilate_triangle |
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AGG_INLINE void dilate_triangle(double x1, double y1, |
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double x2, double y2, |
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double x3, double y3, |
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double *x, double* y, |
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double d) |
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{ |
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double dx1=0.0; |
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double dy1=0.0; |
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double dx2=0.0; |
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double dy2=0.0; |
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double dx3=0.0; |
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double dy3=0.0; |
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double loc = cross_product(x1, y1, x2, y2, x3, y3); |
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if(std::fabs(loc) > intersection_epsilon) |
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{ |
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if(cross_product(x1, y1, x2, y2, x3, y3) > 0.0) |
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{ |
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d = -d; |
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} |
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calc_orthogonal(d, x1, y1, x2, y2, &dx1, &dy1); |
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calc_orthogonal(d, x2, y2, x3, y3, &dx2, &dy2); |
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calc_orthogonal(d, x3, y3, x1, y1, &dx3, &dy3); |
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} |
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*x++ = x1 + dx1; *y++ = y1 + dy1; |
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*x++ = x2 + dx1; *y++ = y2 + dy1; |
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*x++ = x2 + dx2; *y++ = y2 + dy2; |
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*x++ = x3 + dx2; *y++ = y3 + dy2; |
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*x++ = x3 + dx3; *y++ = y3 + dy3; |
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*x++ = x1 + dx3; *y++ = y1 + dy3; |
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} |
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//------------------------------------------------------calc_triangle_area |
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AGG_INLINE double calc_triangle_area(double x1, double y1, |
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double x2, double y2, |
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double x3, double y3) |
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{ |
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return (x1*y2 - x2*y1 + x2*y3 - x3*y2 + x3*y1 - x1*y3) * 0.5; |
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} |
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//-------------------------------------------------------calc_polygon_area |
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template<class Storage> double calc_polygon_area(const Storage& st) |
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{ |
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unsigned i; |
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double sum = 0.0; |
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double x = st[0].x; |
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double y = st[0].y; |
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double xs = x; |
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double ys = y; |
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for(i = 1; i < st.size(); i++) |
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{ |
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const typename Storage::value_type& v = st[i]; |
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sum += x * v.y - y * v.x; |
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x = v.x; |
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y = v.y; |
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} |
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return (sum + x * ys - y * xs) * 0.5; |
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} |
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//------------------------------------------------------------------------ |
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// Tables for fast sqrt |
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extern int16u g_sqrt_table[1024]; |
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extern int8 g_elder_bit_table[256]; |
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//---------------------------------------------------------------fast_sqrt |
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//Fast integer Sqrt - really fast: no cycles, divisions or multiplications |
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#if defined(_MSC_VER) |
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#pragma warning(push) |
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#pragma warning(disable : 4035) //Disable warning "no return value" |
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#endif |
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AGG_INLINE unsigned fast_sqrt(unsigned val) |
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{ |
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#if defined(_M_IX86) && defined(_MSC_VER) && !defined(AGG_NO_ASM) |
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//For Ix86 family processors this assembler code is used. |
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//The key command here is bsr - determination the number of the most |
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//significant bit of the value. For other processors |
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//(and maybe compilers) the pure C "#else" section is used. |
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__asm |
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{ |
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mov ebx, val |
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mov edx, 11 |
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bsr ecx, ebx |
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sub ecx, 9 |
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jle less_than_9_bits |
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shr ecx, 1 |
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adc ecx, 0 |
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sub edx, ecx |
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shl ecx, 1 |
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shr ebx, cl |
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less_than_9_bits: |
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xor eax, eax |
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mov ax, g_sqrt_table[ebx*2] |
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mov ecx, edx |
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shr eax, cl |
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} |
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#else |
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//This code is actually pure C and portable to most |
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//arcitectures including 64bit ones. |
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unsigned t = val; |
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int bit=0; |
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unsigned shift = 11; |
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//The following piece of code is just an emulation of the |
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//Ix86 assembler command "bsr" (see above). However on old |
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//Intels (like Intel MMX 233MHz) this code is about twice |
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//faster (sic!) then just one "bsr". On PIII and PIV the |
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//bsr is optimized quite well. |
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bit = t >> 24; |
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if(bit) |
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{ |
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bit = g_elder_bit_table[bit] + 24; |
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} |
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else |
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{ |
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bit = (t >> 16) & 0xFF; |
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if(bit) |
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{ |
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bit = g_elder_bit_table[bit] + 16; |
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} |
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else |
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{ |
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bit = (t >> 8) & 0xFF; |
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if(bit) |
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{ |
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bit = g_elder_bit_table[bit] + 8; |
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} |
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else |
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{ |
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bit = g_elder_bit_table[t]; |
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} |
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} |
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} |
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//This code calculates the sqrt. |
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bit -= 9; |
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if(bit > 0) |
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{ |
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bit = (bit >> 1) + (bit & 1); |
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shift -= bit; |
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val >>= (bit << 1); |
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} |
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return g_sqrt_table[val] >> shift; |
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#endif |
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} |
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#if defined(_MSC_VER) |
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#pragma warning(pop) |
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#endif |
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//--------------------------------------------------------------------besj |
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// Function BESJ calculates Bessel function of first kind of order n |
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// Arguments: |
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// n - an integer (>=0), the order |
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// x - value at which the Bessel function is required |
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//-------------------- |
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// C++ Mathematical Library |
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// Convereted from equivalent FORTRAN library |
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// Converetd by Gareth Walker for use by course 392 computational project |
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// All functions tested and yield the same results as the corresponding |
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// FORTRAN versions. |
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// |
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// If you have any problems using these functions please report them to |
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// M.Muldoon@UMIST.ac.uk |
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// |
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// Documentation available on the web |
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// http://www.ma.umist.ac.uk/mrm/Teaching/392/libs/392.html |
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// Version 1.0 8/98 |
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// 29 October, 1999 |
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//-------------------- |
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// Adapted for use in AGG library by Andy Wilk (castor.vulgaris@gmail.com) |
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//------------------------------------------------------------------------ |
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inline double besj(double x, int n) |
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{ |
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if(n < 0) |
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{ |
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return 0; |
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} |
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double d = 1E-6; |
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double b = 0; |
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if(std::fabs(x) <= d) |
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{ |
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if(n != 0) return 0; |
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return 1; |
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} |
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double b1 = 0; // b1 is the value from the previous iteration |
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// Set up a starting order for recurrence |
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int m1 = (int)std::fabs(x) + 6; |
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if(std::fabs(x) > 5) |
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{ |
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m1 = (int)(std::fabs(1.4 * x + 60 / x)); |
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} |
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int m2 = (int)(n + 2 + std::fabs(x) / 4); |
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if (m1 > m2) |
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{ |
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m2 = m1; |
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} |
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// Apply recurrence down from curent max order |
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for(;;) |
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{ |
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double c3 = 0; |
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double c2 = 1E-30; |
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double c4 = 0; |
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int m8 = 1; |
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if (m2 / 2 * 2 == m2) |
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{ |
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m8 = -1; |
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} |
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int imax = m2 - 2; |
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for (int i = 1; i <= imax; i++) |
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{ |
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double c6 = 2 * (m2 - i) * c2 / x - c3; |
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c3 = c2; |
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c2 = c6; |
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if(m2 - i - 1 == n) |
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{ |
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b = c6; |
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} |
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m8 = -1 * m8; |
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if (m8 > 0) |
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{ |
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c4 = c4 + 2 * c6; |
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} |
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} |
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double c6 = 2 * c2 / x - c3; |
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if(n == 0) |
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{ |
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b = c6; |
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} |
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c4 += c6; |
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b /= c4; |
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if(std::fabs(b - b1) < d) |
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{ |
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return b; |
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} |
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b1 = b; |
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m2 += 3; |
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} |
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} |
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} |
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#endif
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