reach.js

'use strict';

var ever = require('ever');
var inherits = require('inherits');
var EventEmitter = require('events').EventEmitter;
var fract = require('fract');

module.exports = function(game, opts) {
  return new Reach(game, opts);
};

module.exports.pluginInfo = {
};

function Reach(game, opts) {
  this.game = game;
  opts = opts || {};
  opts.reachDistance = opts.reachDistance || 8;
  opts.mouseButton = opts.mouseButton !== undefined ? opts.mouseButton : 0; // left

  this.opts = opts;
  this.currentTarget = null;
  this.havePointer = false;

  this.enable();
}


Reach.prototype.enable = function() {
  var self = this;

  if (this.game.isClient) {
    if (self.game.shell) {
      // game-shell
      Object.defineProperty(self, 'havePointer', {get: function() {
        return self.game.shell.pointerLock;
      }});
    } else if (this.game.interact) {
      // interact
      this.game.interact.on('attain', function() {
        self.havePointer = true;
      });

      this.game.interact.on('release', function() {
        self.havePointer = false;
      });
    } else {
      throw new Error('voxel-reach requires interact or game-shell');
    }
  }

  // Continuously fired events while button is held down (from voxel-engine)
  function fire(fireTarget, state) {
    /*jshint unused:false*/
    var action, target;

    action = self.action(state);
    if (!action) {
      return;
    }

    target = self.specifyTarget();

    if (action === 'mining' && (self.currentTarget || target)) {
      // changing target while mouse held (moving mouse)
      if (!targetsEqual(target, self.currentTarget)) {
        self.emit('stop mining', self.currentTarget);
        self.emit('start mining', target);
      }
    }
    self.currentTarget = target;

    self.emit(action, target);
  }

  // Edge triggered
  // TODO: refactor
  function mousedown(ev) {
    if (!self.havePointer) return;
    if (ev.button !== self.opts.mouseButton) return; 
    self.emit('start mining', self.specifyTarget());
  }

  function mouseup(ev) {
    if (!self.havePointer) return;
    if (ev.button !== self.opts.mouseButton)  return;
    self.currentTarget = null;
    self.emit('stop mining', self.specifyTarget());
  }

  this.game.on('fire', fire);
  if (this.game.isClient) {
    ever(document.body).on('mousedown', mousedown);
    ever(document.body).on('mouseup', mouseup);
  }

  // Save callbacks for removing in disable()
  this.fire = fire;
  this.mousedown = mousedown;
  this.mouseup = mouseup;
};

Reach.prototype.disable = function() {
  this.game.removeListener('fire', this.fire);
  if (this.game.isClient) {
    ever(document.body).removeListener('mousedown', this.mousedown);
    ever(document.body).removeListener('mouseup', this.mouseup);
  }
};

function targetsEqual(a, b) {
  var strA = (a && a.voxel) ? a.voxel.join(',') : 'none';
  var strB = (b && b.voxel) ? b.voxel.join(',') : 'none';
  return strA === strB;
}

// Raytrace and get the hit voxel, side, and subcoordinates for passing to events
Reach.prototype.specifyTarget = function() {
  var sub, side, hit, value;

  hit = this.game.raycastVoxels(this.game.cameraPosition(), this.game.cameraVector(), this.opts.reachDistance);

  if (!hit) {
    // air
    return false;
  }

  // relative position within voxel where it was hit, range (1..0), for example (0.5, 0.5) is center:

  // (1,1)--(0,1)
  //   |      |
  //   |      |
  // (1,0)--(0,0)

  sub = [fract(hit.position[0]), fract(hit.position[1]), fract(hit.position[2])];
  // remove coordinate from direction, since it is always 0 (within epilson); convert 3D -> 2D
  var fix = ((hit.normal.indexOf(1) + 1) || (hit.normal.indexOf(-1) + 1)) - 1; // TODO: deobfuscate
  sub.splice(fix, 1);

  side = this.normalToCardinal(hit.normal);

  value = this.game.getBlock(hit.voxel);

  return {voxel: hit.voxel, adjacent: hit.adjacent, side: side, sub: sub, normal: hit.normal, value:value};
};

Reach.prototype.normalToCardinal = function(normal) {
  return {
    "1,0,0": "east", // TODO: double-check these conventions
    "-1,0,0": "west",
    "0,1,0": "top",
    "0,-1,0": "bottom",
    "0,0,1": "south",
    "0,0,-1": "north"
  }[normal];
};

Reach.prototype.cardinalToNormal = function(direction) {
  return {
    "east": [1, 0, 0],
    "west": [-1, 0, 0],
    "top": [0, 1, 0],
    "bottom": [0, -1, 0],
    "south": [0, 0, 1],
    "north": [0, 0, -1]
  }[direction];
};

Reach.prototype.action = function(kb_state) {
  if (kb_state.fire) {
    // left-click (hold) = mining
    return 'mining';
  } else if (kb_state.firealt) {
    // right-click = use
    return 'use';
  // TODO: middle-click = pick
  } else {
    return undefined;
  }
};

inherits(Reach, EventEmitter);