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Diffstat (limited to 'agg/inc/agg_span_gouraud.h')
-rwxr-xr-x | agg/inc/agg_span_gouraud.h | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/agg/inc/agg_span_gouraud.h b/agg/inc/agg_span_gouraud.h new file mode 100755 index 000000000000..76747899b5fc --- /dev/null +++ b/agg/inc/agg_span_gouraud.h @@ -0,0 +1,180 @@ +//---------------------------------------------------------------------------- +// 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_SPAN_GOURAUD_INCLUDED +#define AGG_SPAN_GOURAUD_INCLUDED + +#include "agg_basics.h" +#include "agg_math.h" +#include "agg_span_generator.h" + +namespace agg +{ + + //============================================================span_gouraud + template<class ColorT, class Allocator> + class span_gouraud : public span_generator<ColorT, Allocator> + { + public: + typedef ColorT color_type; + typedef Allocator alloc_type; + + struct coord_type + { + double x; + double y; + color_type color; + }; + + //-------------------------------------------------------------------- + span_gouraud(alloc_type& alloc) : + span_generator<color_type, alloc_type>(alloc), + m_vertex(0) + { + m_cmd[0] = path_cmd_stop; + } + + //-------------------------------------------------------------------- + span_gouraud(alloc_type& alloc, + const color_type& c1, + const color_type& c2, + const color_type& c3, + double x1, double y1, + double x2, double y2, + double x3, double y3, + double d) : + span_generator<color_type, alloc_type>(alloc) + { + colors(c1, c2, c3); + triangle(x1, y1, x2, y2, x3, y3, d); + } + + //-------------------------------------------------------------------- + void colors(ColorT c1, ColorT c2, ColorT c3) + { + m_coord[0].color = c1; + m_coord[1].color = c2; + m_coord[2].color = c3; + } + + //-------------------------------------------------------------------- + // Sets the triangle and dilates it if needed. + // The trick here is to calculate beveled joins in the vertices of the + // triangle and render it as a 6-vertex polygon. + // It's necessary to achieve numerical stability. + // However, the coordinates to interpolate colors are calculated + // as miter joins (calc_intersection). + void triangle(double x1, double y1, + double x2, double y2, + double x3, double y3, + double d) + { + m_coord[0].x = m_x[0] = x1; + m_coord[0].y = m_y[0] = y1; + m_coord[1].x = m_x[1] = x2; + m_coord[1].y = m_y[1] = y2; + m_coord[2].x = m_x[2] = x3; + m_coord[2].y = m_y[2] = y3; + m_cmd[0] = path_cmd_move_to; + m_cmd[1] = path_cmd_line_to; + m_cmd[2] = path_cmd_line_to; + m_cmd[3] = path_cmd_stop; + + if(d != 0.0) + { + dilate_triangle(m_coord[0].x, m_coord[0].y, + m_coord[1].x, m_coord[1].y, + m_coord[2].x, m_coord[2].y, + m_x, m_y, d); + + calc_intersection(m_x[4], m_y[4], m_x[5], m_y[5], + m_x[0], m_y[0], m_x[1], m_y[1], + &m_coord[0].x, &m_coord[0].y); + + calc_intersection(m_x[0], m_y[0], m_x[1], m_y[1], + m_x[2], m_y[2], m_x[3], m_y[3], + &m_coord[1].x, &m_coord[1].y); + + calc_intersection(m_x[2], m_y[2], m_x[3], m_y[3], + m_x[4], m_y[4], m_x[5], m_y[5], + &m_coord[2].x, &m_coord[2].y); + m_cmd[3] = path_cmd_line_to; + m_cmd[4] = path_cmd_line_to; + m_cmd[5] = path_cmd_line_to; + m_cmd[6] = path_cmd_stop; + } + } + + //-------------------------------------------------------------------- + // Vertex Source Interface to feed the coordinates to the rasterizer + void rewind(unsigned) + { + m_vertex = 0; + } + + //-------------------------------------------------------------------- + unsigned vertex(double* x, double* y) + { + *x = m_x[m_vertex]; + *y = m_y[m_vertex]; + return m_cmd[m_vertex++]; + } + + + + protected: + //-------------------------------------------------------------------- + void arrange_vertices(coord_type* coord) const + { + coord[0] = m_coord[0]; + coord[1] = m_coord[1]; + coord[2] = m_coord[2]; + + if(m_coord[0].y > m_coord[2].y) + { + coord[0] = m_coord[2]; + coord[2] = m_coord[0]; + } + + coord_type tmp; + if(coord[0].y > coord[1].y) + { + tmp = coord[1]; + coord[1] = coord[0]; + coord[0] = tmp; + } + + if(coord[1].y > coord[2].y) + { + tmp = coord[2]; + coord[2] = coord[1]; + coord[1] = tmp; + } + } + + + private: + //-------------------------------------------------------------------- + coord_type m_coord[3]; + double m_x[8]; + double m_y[8]; + unsigned m_cmd[8]; + unsigned m_vertex; + }; + +} + +#endif + |