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Diffstat (limited to 'agg/inc/agg_math.h')
| -rwxr-xr-x | agg/inc/agg_math.h | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/agg/inc/agg_math.h b/agg/inc/agg_math.h new file mode 100755 index 000000000000..4aef4df9638e --- /dev/null +++ b/agg/inc/agg_math.h @@ -0,0 +1,247 @@ +//---------------------------------------------------------------------------- +// Anti-Grain Geometry - Version 2.3 +// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com) +// +// Permission to copy, use, modify, sell and distribute this software +// is granted provided this copyright notice appears in all copies. +// This software is provided "as is" without express or implied +// warranty, and with no claim as to its suitability for any purpose. +// +//---------------------------------------------------------------------------- +// Contact: mcseem@antigrain.com +// mcseemagg@yahoo.com +// http://www.antigrain.com +//---------------------------------------------------------------------------- + +#ifndef AGG_MATH_INCLUDED +#define AGG_MATH_INCLUDED + +#include <math.h> +#include "agg_basics.h" + +namespace agg +{ + + const double intersection_epsilon = 1.0e-8; + + //------------------------------------------------------calc_point_location + AGG_INLINE double calc_point_location(double x1, double y1, + double x2, double y2, + double x, double y) + { + return (x - x2) * (y2 - y1) - (y - y2) * (x2 - x1); + } + + + //--------------------------------------------------------point_in_triangle + AGG_INLINE bool point_in_triangle(double x1, double y1, + double x2, double y2, + double x3, double y3, + double x, double y) + { + bool cp1 = calc_point_location(x1, y1, x2, y2, x, y) < 0.0; + bool cp2 = calc_point_location(x2, y2, x3, y3, x, y) < 0.0; + bool cp3 = calc_point_location(x3, y3, x1, y1, x, y) < 0.0; + return cp1 == cp2 && cp2 == cp3 && cp3 == cp1; + } + + + //-----------------------------------------------------------calc_distance + AGG_INLINE double calc_distance(double x1, double y1, double x2, double y2) + { + double dx = x2-x1; + double dy = y2-y1; + return sqrt(dx * dx + dy * dy); + } + + + //------------------------------------------------calc_point_line_distance + AGG_INLINE double calc_point_line_distance(double x1, double y1, + double x2, double y2, + double x, double y) + { + double dx = x2-x1; + double dy = y2-y1; + return ((x - x2) * dy - (y - y2) * dx) / sqrt(dx * dx + dy * dy); + } + + + //-------------------------------------------------------calc_intersection + AGG_INLINE bool calc_intersection(double ax, double ay, double bx, double by, + double cx, double cy, double dx, double dy, + double* x, double* y) + { + double num = (ay-cy) * (dx-cx) - (ax-cx) * (dy-cy); + double den = (bx-ax) * (dy-cy) - (by-ay) * (dx-cx); + if(fabs(den) < intersection_epsilon) return false; + double r = num / den; + *x = ax + r * (bx-ax); + *y = ay + r * (by-ay); + return true; + } + + + //--------------------------------------------------------calc_orthogonal + AGG_INLINE void calc_orthogonal(double thickness, + double x1, double y1, + double x2, double y2, + double* x, double* y) + { + double dx = x2 - x1; + double dy = y2 - y1; + double d = sqrt(dx*dx + dy*dy); + *x = thickness * dy / d; + *y = thickness * dx / d; + } + + + //--------------------------------------------------------dilate_triangle + AGG_INLINE void dilate_triangle(double x1, double y1, + double x2, double y2, + double x3, double y3, + double *x, double* y, + double d) + { + double dx1=0.0; + double dy1=0.0; + double dx2=0.0; + double dy2=0.0; + double dx3=0.0; + double dy3=0.0; + double loc = calc_point_location(x1, y1, x2, y2, x3, y3); + if(fabs(loc) > intersection_epsilon) + { + if(calc_point_location(x1, y1, x2, y2, x3, y3) > 0.0) + { + d = -d; + } + calc_orthogonal(d, x1, y1, x2, y2, &dx1, &dy1); + calc_orthogonal(d, x2, y2, x3, y3, &dx2, &dy2); + calc_orthogonal(d, x3, y3, x1, y1, &dx3, &dy3); + } + *x++ = x1 + dx1; *y++ = y1 - dy1; + *x++ = x2 + dx1; *y++ = y2 - dy1; + *x++ = x2 + dx2; *y++ = y2 - dy2; + *x++ = x3 + dx2; *y++ = y3 - dy2; + *x++ = x3 + dx3; *y++ = y3 - dy3; + *x++ = x1 + dx3; *y++ = y1 - dy3; + } + + //-------------------------------------------------------calc_polygon_area + template<class Storage> double calc_polygon_area(const Storage& st) + { + unsigned i; + double sum = 0.0; + double x = st[0].x; + double y = st[0].y; + double xs = x; + double ys = y; + + for(i = 1; i < st.size(); i++) + { + const typename Storage::value_type& v = st[i]; + sum += x * v.y - y * v.x; + x = v.x; + y = v.y; + } + return (sum + x * ys - y * xs) * 0.5; + } + + //------------------------------------------------------------------------ + // Tables for fast sqrt + extern int16u g_sqrt_table[1024]; + extern int8 g_elder_bit_table[256]; + + + //---------------------------------------------------------------fast_sqrt + //Fast integer Sqrt - really fast: no cycles, divisions or multiplications + #if defined(_MSC_VER) + #pragma warning(push) + #pragma warning(disable : 4035) //Disable warning "no return value" + #endif + AGG_INLINE unsigned fast_sqrt(unsigned val) + { + #if defined(_M_IX86) && defined(_MSC_VER) && !defined(AGG_NO_ASM) + //For Ix86 family processors this assembler code is used. + //The key command here is bsr - determination the number of the most + //significant bit of the value. For other processors + //(and maybe compilers) the pure C "#else" section is used. + __asm + { + mov ebx, val + mov edx, 11 + bsr ecx, ebx + sub ecx, 9 + jle less_than_9_bits + shr ecx, 1 + adc ecx, 0 + sub edx, ecx + shl ecx, 1 + shr ebx, cl + less_than_9_bits: + xor eax, eax + mov ax, g_sqrt_table[ebx*2] + mov ecx, edx + shr eax, cl + } + #else + + //This code is actually pure C and portable to most + //arcitectures including 64bit ones. + unsigned t = val; + int bit=0; + unsigned shift = 11; + + //The following piece of code is just an emulation of the + //Ix86 assembler command "bsr" (see above). However on old + //Intels (like Intel MMX 233MHz) this code is about twice + //faster (sic!) then just one "bsr". On PIII and PIV the + //bsr is optimized quite well. + bit = t >> 24; + if(bit) + { + bit = g_elder_bit_table[bit] + 24; + } + else + { + bit = (t >> 16) & 0xFF; + if(bit) + { + bit = g_elder_bit_table[bit] + 16; + } + else + { + bit = (t >> 8) & 0xFF; + if(bit) + { + bit = g_elder_bit_table[bit] + 8; + } + else + { + bit = g_elder_bit_table[t]; + } + } + } + + //This is calculation sqrt itself. + bit -= 9; + if(bit > 0) + { + bit = (bit >> 1) + (bit & 1); + shift -= bit; + val >>= (bit << 1); + } + return g_sqrt_table[val] >> shift; + #endif + } + #if defined(_MSC_VER) + #pragma warning(pop) + #endif + + + + +} + + +#endif |