gistfile1.rb

   inline do |builder|
        builder.prefix %{ 
         VALUE
         intersect(VALUE s, VALUE o) { 
                float x, y, y_offset, x_offset, ox, oy, ox_offset, oy_offset;
                
                x = rb_iv_get(s, "@x");
                y = rb_iv_get(s, "@y");
                x_offset = rb_iv_get(s, "@x_offset");
                y_offset = rb_iv_get(s, "@y_offset");
 
                ox = rb_iv_get(o, "@x");
                oy = rb_iv_get(o, "@y");
                ox_offset = rb_iv_get(o, "@x_offset");
                oy_offset = rb_iv_get(o, "@y_offset");
 

                if(y - y_offset < oy + oy_offset && y + y_offset > oy - oy_offset &&
                       x - x_offset < ox + ox_offset && x + x_offset > ox - ox_offset)
                    return Qtrue;
                else
                    return Qfalse;

          }
        }

        builder.c %{
         VALUE
         check_actor_collision() { 
             VALUE world, thing;
             
             world = rb_iv_get(self, "@world");
             
             int i;
             for(i = 0; i < RARRAY(world)->len; i++) { 
                 thing = rb_ary_entry(world, i);
                 
                 if(thing == self) continue;

                 if(intersect(self, thing)) {
                   rb_funcall(self, rb_intern("do_collision"), thing);
                   rb_funcall(thing, rb_intern("do_collision"), self);
                 }
              }
              return Qnil;
          }
        }

    end