src/lua/gui-line.cpp

   1 #include "lua/internal.hpp"
   2 #include "library/framebuffer.hpp"
   3
   4 namespace
   5 {
   6         struct render_object_line : public render_object
   7         {
   8                 render_object_line(int32_t _x1, int32_t _x2, int32_t _y1, int32_t _y2, premultiplied_color _color)
   9                         throw()
  10                         : x1(_x1), y1(_y1), x2(_x2), y2(_y2), color(_color) {}
  11                 ~render_object_line() throw() {}
  12                 template<bool X> void op(struct framebuffer<X>& scr) throw()
  13                 {
  14                         size_t swidth = scr.get_width();
  15                         size_t sheight = scr.get_height();
  16                         int32_t _x1 = x1 + scr.get_origin_x();
  17                         int32_t _x2 = x2 + scr.get_origin_x();
  18                         int32_t _y1 = y1 + scr.get_origin_y();
  19                         int32_t _y2 = y2 + scr.get_origin_y();
  20                         color.set_palette(scr);
  21                         int32_t xdiff = _x2 - _x1;
  22                         int32_t ydiff = _y2 - _y1;
  23                         if(xdiff < 0)
  24                                 xdiff = -xdiff;
  25                         if(ydiff < 0)
  26                                 ydiff = -ydiff;
  27                         if(xdiff >= ydiff) {
  28                                 //X-major line.
  29                                 if(x2 < x1) {
  30                                         //Swap points so that x1 < x2.
  31                                         std::swap(_x1, _x2);
  32                                         std::swap(_y1, _y2);
  33                                 }
  34                                 //The slope of the line is (y2 - y1) / (x2 - x1) = +-ydiff / xdiff
  35                                 int32_t y = _y1;
  36                                 int32_t ysub = 0;
  37                                 for(int32_t x = _x1; x <= _x2; x++) {
  38                                         if(x < 0 || static_cast<uint32_t>(x) >= swidth)
  39                                                 goto nodraw1;
  40                                         if(y < 0 || static_cast<uint32_t>(y) >= sheight)
  41                                                 goto nodraw1;
  42                                         color.apply(scr.rowptr(y)[x]);
  43 nodraw1:
  44                                         ysub += ydiff;
  45                                         if(ysub >= xdiff) {
  46                                                 ysub -= xdiff;
  47                                                 if(_y2 > _y1)
  48                                                         y++;
  49                                                 else
  50                                                         y--;
  51                                         }
  52                                 }
  53                         } else {
  54                                 //Y-major line.
  55                                 if(_x2 < _x1) {
  56                                         //Swap points so that y1 < y2.
  57                                         std::swap(_x1, _x2);
  58                                         std::swap(_y1, _y2);
  59                                 }
  60                                 //The slope of the line is (x2 - x1) / (y2 - y1) = +-xdiff / ydiff
  61                                 int32_t x = _x1;
  62                                 int32_t xsub = 0;
  63                                 for(int32_t y = _y1; y <= _y2; y++) {
  64                                         if(x < 0 || static_cast<uint32_t>(x) >= swidth)
  65                                                 goto nodraw2;
  66                                         if(y < 0 || static_cast<uint32_t>(y) >= sheight)
  67                                                 goto nodraw2;
  68                                         color.apply(scr.rowptr(y)[x]);
  69 nodraw2:
  70                                         xsub += xdiff;
  71                                         if(xsub >= ydiff) {
  72                                                 xsub -= ydiff;
  73                                                 if(_x2 > _x1)
  74                                                         x++;
  75                                                 else
  76                                                         x--;
  77                                         }
  78                                 }
  79                         }
  80                 }
  81                 void operator()(struct framebuffer<true>& scr) throw()  { op(scr); }
  82                 void operator()(struct framebuffer<false>& scr) throw() { op(scr); }
  83         private:
  84                 int32_t x1;
  85                 int32_t y1;
  86                 int32_t x2;
  87                 int32_t y2;
  88                 premultiplied_color color;
  89         };
  90
  91         function_ptr_luafun gui_pixel(LS, "gui.line", [](lua_state& L, const std::string& fname) -> int {
  92                 if(!lua_render_ctx)
  93                         return 0;
  94                 int64_t color = 0xFFFFFFU;
  95                 int32_t x1 = L.get_numeric_argument<int32_t>(1, fname.c_str());
  96                 int32_t y1 = L.get_numeric_argument<int32_t>(2, fname.c_str());
  97                 int32_t x2 = L.get_numeric_argument<int32_t>(3, fname.c_str());
  98                 int32_t y2 = L.get_numeric_argument<int32_t>(4, fname.c_str());
  99                 L.get_numeric_argument<int64_t>(5, color, fname.c_str());
 100                 premultiplied_color pcolor(color);
 101                 lua_render_ctx->queue->create_add<render_object_line>(x1, x2, y1, y2, pcolor);
 102                 return 0;
 103         });
 104 }