Forums » Code » Accelerometer control system

This doesn't work on iOS and requires JQuery

I use this code on Blackberry Playbook and Nexus 7

The Nexus 7 needs the right and left control values reversed

The following is a big hack that overrides the built-in control system but makes for very intuitive play.

On the tested devices you can tilt the tablet left / right to move in that direction, touch anywhere on the screen to fire and flip the device away from you a little to jump.

It's extensible - you could easily use the Z-Axis as well or reverse the jump code for a 'down' command for example

A modification I'll be making shortly will allow different parts of the screen to do different things based on where the touch event takes place

The touchmove binding prevents scrolling of a webview if anyone's wondering

var jumped = 0;
var dbg = true;
var orient = 1;
var shoot = false;

function handleDeviceOrientation(event) 
    {
    if (window.orientation === undefined) {
        return false;
    }
    
    switch(window.orientation) 
        {
        case 0:
            orient = 1;
            break;
        case 180:
            orient = -1;
            break;
        }
    }
    
function handleDeviceMotion(event) 
    {
    ax = event.accelerationIncludingGravity.x * orient;
    ay = event.accelerationIncludingGravity.y * orient;

    ig.input.clearPressed();
    
    if(ax > 4)
        {
        // Right
        ig.input.actions.right = true;
        }
    else
        {
        ig.input.delayedKeyup.right = false;
        }
        
    if(ax < -4)
        {
        // Left
        ig.input.actions.left = true;
        }
    else
        {
        ig.input.delayedKeyup.left = false;
        }
    
    jumper = ay - jumped;
    
    if(jumper > 2)
        {
        // Jump
        ig.input.presses.jump = true;
        }
        
    if(shoot)
        {
        // Jump
        ig.input.presses.shoot = true;
        }
        
    jumped = ay;
    shoot = false;
    }

function doShoot()
    {
    shoot = true;
    }
    
$(document).bind('touchmove', function(e) {
    e.preventDefault();
    window.scroll(0,0);
    return false;
});

$(document).ready(function() {
    handleDeviceOrientation();
    document.addEventListener("touchstart",  doShoot,  false);
    window.addEventListener("orientationchange", handleDeviceOrientation, true);
    if (window.DeviceMotionEvent || window.ondevicemotion) {
        //Check to see if the current application supports the devicemotion
        window.addEventListener("devicemotion", handleDeviceMotion, false);
        jumped = event.accelerationIncludingGravity.y;
    } 
        
    });

Jquery on a mobile device is an overkill why not use jqmobi?