//当单位配置中 keepdist = 1 时，攻击时将尽量保持与目标间的距离为自己的攻击距离
public static void update_keep_atk_range(IBaseUnit sprite, long tm_elasped_s)
{
var pl = sprite.get_pack_data();
if (pl.atking == null)
{
return;
}
if (sprite.has_state(pl_state_type.PST_CANT_MOVE))
{
// can't move
return;
}
var gmap = sprite.gmap;
if (gmap.has_sprite_by_iid(pl.atking.tar_iid))
{
//Utility.trace_err("monster["+this.mondata.iid+"] atking tar_iid[" + this.mondata.atking.tar_iid +"] cur tm[" +cur_clock_tm+"] last_trace_tm ["+ last_trace_target_tm +"] \n");
var target = gmap.map_sprites[pl.atking.tar_iid];
var tar_pl = target.get_pack_data();
double dist_x = pl.x - tar_pl.x;
double dist_y = pl.y - tar_pl.y;
var dist2 = dist_x * dist_x + dist_y * dist_y;
var dist = Math.Sqrt(dist2);
var atk_rang2 = pl.atkrange * pl.atkrange;
// 处于最佳攻击距离
var best_atk_rang = pl.atkrange;
if (dist.CompareTo(best_atk_rang) <= 0)
{
//Utility.trace_info("atk_trace stop:"+dist2+"="+atk_rang2+"\n");
if (pl.moving != null)
{
//// 停止移动
////var cur_grid_pos = {x=(pl.x/game_const.map_grid_pixel), y=(pl.y/game_const.map_grid_pixel)}
//var data = {tm=sys.clock_time()- pl.atking.trace_tm_left, iid=pl.iid, x=pl.x, y=pl.y, face=pl.face};
//// send stop move msg to clients
////gmap.broadcast_map_rpc(10, data);
//sprite.broad_cast_zone_msg_and_self(10, data);
//delete pl.moving;
pl.moving = null;
}
}
else
{
//if(dist > best_atk_rang)
//{
// Utility.trace_info("atk_trace:"+dist+">"+best_atk_rang+"\n");
//}
//else if(dist < best_atk_rang)
//{
// Utility.trace_info("atk_trace:"+dist+"<"+best_atk_rang+"\n");
//}
// 保持距离
//var cur_pos = gmap.get_grid_by_pt(pl.x, pl.y);
//var tar_pos = gmap.get_grid_by_pt(tar_pl.x, tar_pl.y);
//var k = (best_atk_rang / dist);
//var best_pos = {};
//best_pos.x <- (tar_pos.x + (cur_pos.x - tar_pos.x) * k);
//best_pos.y <- (tar_pos.y + (cur_pos.y - tar_pos.y) * k);
// 计算和目标之间的角度atan(a)，范围为[-PI/2, PI/2]，为了获得整个圆周的范围，当(x<0)时角度为：PI+atan(a)
/*
* |
* (-,-)|(+,-)
* -----O------>X
* (-,+)|(+,+)
* |
* \/Y
*/
double alpha = 0;
if (dist != 0)
{
alpha = Math.PI / 2;
if (dist_x != 0)
{
alpha = Math.Atan((dist_y / dist_x));
if (dist_x < 0)
{
alpha += Math.PI;
}
}
else if (dist_y < 0)
{
alpha = -Math.PI / 2;
}
}
//Utility.trace_info("atan("+dist_y+"/"+dist_x+"="+k+")="+alpha+"\n");
// 在最佳攻击距离圈上选取最近可达点
var new_pos = gmap.valpoint_on_round(tar_pl.x, tar_pl.y, best_atk_rang, alpha);
if (new_pos != null)
{
new_pos = gmap.get_grid_by_pt(new_pos.x, new_pos.y);
sprite._move_to(new_pos.x, new_pos.y);
}
//Utility.trace_info("keep range pos:("+tar_pos.x+","+tar_pos.y+","+best_atk_rang+")->("+new_pos.x+","+new_pos.y+")\n");
}
}
}