src/lua/gui-line.cpp

   1 #include "lua/internal.hpp"
   2 #include "library/framebuffer.hpp"
   3 #include "library/lua-framebuffer.hpp"
   4
   5 namespace
   6 {
   7         struct render_object_line : public framebuffer::object
   8         {
   9                 render_object_line(int32_t _x1, int32_t _x2, int32_t _y1, int32_t _y2, framebuffer::color _color)
  10                         throw()
  11                         : x1(_x1), y1(_y1), x2(_x2), y2(_y2), color(_color) {}
  12                 ~render_object_line() throw() {}
  13                 template<bool X> void op(struct framebuffer::fb<X>& scr) throw()
  14                 {
  15                         size_t swidth = scr.get_width();
  16                         size_t sheight = scr.get_height();
  17                         int32_t _x1 = x1 + scr.get_origin_x();
  18                         int32_t _x2 = x2 + scr.get_origin_x();
  19                         int32_t _y1 = y1 + scr.get_origin_y();
  20                         int32_t _y2 = y2 + scr.get_origin_y();
  21                         color.set_palette(scr);
  22                         int32_t xdiff = _x2 - _x1;
  23                         int32_t ydiff = _y2 - _y1;
  24                         if(xdiff < 0)
  25                                 xdiff = -xdiff;
  26                         if(ydiff < 0)
  27                                 ydiff = -ydiff;
  28                         if(xdiff >= ydiff) {
  29                                 //X-major line.
  30                                 if(x2 < x1) {
  31                                         //Swap points so that x1 < x2.
  32                                         std::swap(_x1, _x2);
  33                                         std::swap(_y1, _y2);
  34                                 }
  35                                 //The slope of the line is (y2 - y1) / (x2 - x1) = +-ydiff / xdiff
  36                                 int32_t y = _y1;
  37                                 int32_t ysub = 0;
  38                                 for(int32_t x = _x1; x <= _x2; x++) {
  39                                         if(x < 0 || static_cast<uint32_t>(x) >= swidth)
  40                                                 goto nodraw1;
  41                                         if(y < 0 || static_cast<uint32_t>(y) >= sheight)
  42                                                 goto nodraw1;
  43                                         color.apply(scr.rowptr(y)[x]);
  44 nodraw1:
  45                                         ysub += ydiff;
  46                                         if(ysub >= xdiff) {
  47                                                 ysub -= xdiff;
  48                                                 if(_y2 > _y1)
  49                                                         y++;
  50                                                 else
  51                                                         y--;
  52                                         }
  53                                 }
  54                         } else {
  55                                 //Y-major line.
  56                                 if(_y2 < _y1) {
  57                                         //Swap points so that y1 < y2.
  58                                         std::swap(_x1, _x2);
  59                                         std::swap(_y1, _y2);
  60                                 }
  61                                 //The slope of the line is (x2 - x1) / (y2 - y1) = +-xdiff / ydiff
  62                                 int32_t x = _x1;
  63                                 int32_t xsub = 0;
  64                                 for(int32_t y = _y1; y <= _y2; y++) {
  65                                         if(x < 0 || static_cast<uint32_t>(x) >= swidth)
  66                                                 goto nodraw2;
  67                                         if(y < 0 || static_cast<uint32_t>(y) >= sheight)
  68                                                 goto nodraw2;
  69                                         color.apply(scr.rowptr(y)[x]);
  70 nodraw2:
  71                                         xsub += xdiff;
  72                                         if(xsub >= ydiff) {
  73                                                 xsub -= ydiff;
  74                                                 if(_x2 > _x1)
  75                                                         x++;
  76                                                 else
  77                                                         x--;
  78                                         }
  79                                 }
  80                         }
  81                 }
  82                 void operator()(struct framebuffer::fb<true>& scr) throw()  { op(scr); }
  83                 void operator()(struct framebuffer::fb<false>& scr) throw() { op(scr); }
  84                 void clone(framebuffer::queue& q) const throw(std::bad_alloc) { q.clone_helper(this); }
  85         private:
  86                 int32_t x1;
  87                 int32_t y1;
  88                 int32_t x2;
  89                 int32_t y2;
  90                 framebuffer::color color;
  91         };
  92
  93         int line(lua::state& L, lua::parameters& P)
  94         {
  95                 int32_t x1, y1, x2, y2;
  96                 framebuffer::color pcolor;
  97
  98                 if(!lua_render_ctx) return 0;
  99
 100                 P(x1, y1, x2, y2, P.optional(pcolor, 0xFFFFFFU));
 101
 102                 lua_render_ctx->queue->create_add<render_object_line>(x1, x2, y1, y2, pcolor);
 103                 return 0;
 104         }
 105
 106         lua::functions line_fns(lua_func_misc, "gui", {
 107                 {"line", line},
 108         });
 109 }