engine/key_handler.js

   1 /*
   2  * key_handler.js
   3  *
   4  * Copyright 2020 Elias Fleckenstein <eliasfleckenstein@web.de>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  19  * MA 02110-1301, USA.
  20  *
  21  *
  22  */
  23 dragonblocks.KeyHandler = class{
  24         constructor(){
  25                 this.locked = {};
  26                 this.upHandlers = {};
  27                 this.downHandlers = {};
  28                 addEventListener("keydown", event => {dragonblocks.keyHandler.handler(event)});
  29                 addEventListener("keyup", event => {dragonblocks.keyHandler.handler(event)});
  30                 addEventListener("wheel", event => {dragonblocks.keyHandler.handler(event)});
  31         }
  32         lock(key){
  33                 this.locked[key] = true;
  34         }
  35         lockAll(){
  36                 for(let key in this.upHandlers)
  37                         this.lock(key);
  38                 for(let key in this.downHandlers)
  39                         this.lock(key);
  40         }
  41         unlock(key){
  42                 dragonblocks.keyHandler.locked[key] = false;
  43         }
  44         unlockAll(){
  45                 for(let key in this.locked)
  46                         this.unlock(key);
  47         }
  48         down(key, func){
  49                 this.downHandlers[key] = func;
  50                 this.lock(key);
  51         }
  52         up(key, func){
  53                 this.upHandlers[key] = func;
  54                 this.lock(key);
  55         }
  56         handler(event){
  57                 switch(event.type){
  58                         case "keydown":
  59                         case "keypress":
  60                                 if(this.locked[event.key])
  61                                         return;
  62                                 if(this.downHandlers[event.key]){
  63                                         event.preventDefault();
  64                                         (this.downHandlers[event.key])();
  65                                 }
  66                                 break;
  67                         case "keyup":
  68                                 if(this.locked[event.key])
  69                                         return;
  70                                 if(this.upHandlers[event.key]){
  71                                         event.preventDefault();
  72                                         (this.upHandlers[event.key])();
  73                                 }
  74                                 break;
  75                         case "wheel":
  76                                 if(this.locked["scroll"])
  77                                         return;
  78                                 if(event.deltaY > 0 && this.downHandlers["scroll"]){
  79                                                 event.preventDefault();
  80                                                 (this.downHandlers["scroll"])();
  81                                 }
  82                                 else if(this.upHandlers["scroll"]){
  83                                                 event.preventDefault();
  84                                                 (this.upHandlers["scroll"])();
  85                                 }
  86                                 break;
  87                 }
  88         }
  89 }
  90 dragonblocks.keyHandler = new dragonblocks.KeyHandler();
  91 dragonblocks.registerOnStarted(_ => {
  92         dragonblocks.keyHandler.unlockAll();
  93 });