src/lua/gui-line.cpp

   1 #include "core/lua-int.hpp"
   2 #include "core/render.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                 void operator()(struct screen& scr) throw()
  13                 {
  14                         color.set_palette(scr);
  15                         int32_t xdiff = x2 - x1;
  16                         int32_t ydiff = y2 - y1;
  17                         if(xdiff < 0)
  18                                 xdiff = -xdiff;
  19                         if(ydiff < 0)
  20                                 ydiff = -ydiff;
  21                         if(xdiff >= ydiff) {
  22                                 //X-major line.
  23                                 if(x2 < x1) {
  24                                         //Swap points so that x1 < x2.
  25                                         std::swap(x1, x2);
  26                                         std::swap(y1, y2);
  27                                 }
  28                                 //The slope of the line is (y2 - y1) / (x2 - x1) = +-ydiff / xdiff
  29                                 int32_t y = y1;
  30                                 int32_t ysub = 0;
  31                                 for(int32_t x = x1; x <= x2; x++) {
  32                                         if(x < 0 || static_cast<uint32_t>(x) >= scr.width)
  33                                                 goto nodraw1;
  34                                         if(y < 0 || static_cast<uint32_t>(y) >= scr.height)
  35                                                 goto nodraw1;
  36                                         color.apply(scr.rowptr(y)[x]);
  37 nodraw1:
  38                                         ysub += ydiff;
  39                                         if(ysub >= xdiff) {
  40                                                 ysub -= xdiff;
  41                                                 if(y2 > y1)
  42                                                         y++;
  43                                                 else
  44                                                         y--;
  45                                         }
  46                                 }
  47                         } else {
  48                                 //Y-major line.
  49                                 if(x2 < x1) {
  50                                         //Swap points so that y1 < y2.
  51                                         std::swap(x1, x2);
  52                                         std::swap(y1, y2);
  53                                 }
  54                                 //The slope of the line is (x2 - x1) / (y2 - y1) = +-xdiff / ydiff
  55                                 int32_t x = x1;
  56                                 int32_t xsub = 0;
  57                                 for(int32_t y = y1; y <= y2; y++) {
  58                                         if(x < 0 || static_cast<uint32_t>(x) >= scr.width)
  59                                                 goto nodraw2;
  60                                         if(y < 0 || static_cast<uint32_t>(y) >= scr.height)
  61                                                 goto nodraw2;
  62                                         color.apply(scr.rowptr(y)[x]);
  63 nodraw2:
  64                                         xsub += xdiff;
  65                                         if(xsub >= ydiff) {
  66                                                 xsub -= ydiff;
  67                                                 if(x2 > x1)
  68                                                         x++;
  69                                                 else
  70                                                         x--;
  71                                         }
  72                                 }
  73                         }
  74                 }
  75         private:
  76                 int32_t x1;
  77                 int32_t y1;
  78                 int32_t x2;
  79                 int32_t y2;
  80                 premultiplied_color color;
  81         };
  82
  83         function_ptr_luafun gui_pixel("gui.line", [](lua_State* LS, const std::string& fname) -> int {
  84                 if(!lua_render_ctx)
  85                         return 0;
  86                 int64_t color = 0xFFFFFFU;
  87                 int32_t x1 = get_numeric_argument<int32_t>(LS, 1, fname.c_str());
  88                 int32_t y1 = get_numeric_argument<int32_t>(LS, 2, fname.c_str());
  89                 int32_t x2 = get_numeric_argument<int32_t>(LS, 3, fname.c_str());
  90                 int32_t y2 = get_numeric_argument<int32_t>(LS, 4, fname.c_str());
  91                 get_numeric_argument<int64_t>(LS, 5, color, fname.c_str());
  92                 premultiplied_color pcolor(color);
  93                 lua_render_ctx->queue->add(*new render_object_line(x1, x2, y1, y2, pcolor));
  94                 return 0;
  95         });
  96 }