How to get input from javascript without stutters between changing keys pressed

Question

I am currently doing this for input handling:

var upKey = false;
var downKey = false;
var leftKey = false;
var rightKey = false;

var sqrt2over2 = 0.707106781;
var MoveSpeed = 20.0;
var Horizontal = false;
var Vertical = false;

document.onkeyup=function(e){
    if(e.which == 87)
    {
        Vertical = false;
        upKey = false;
    }
    if(e.which == 83)
    {
        Vertical = false;
        downKey = false;
    }
    if(e.which == 65)
    {
        Horizontal = false;
        leftKey = false;
    }
    if(e.which == 68)
    {
        Horizontal = false;
        rightKey = false;
    }
}

document.onkeydown=function(e){
    //Up arrow key
    if(e.which == 87) upKey = true;
    //Down arrow key
    if(e.which == 83) downKey = true;
    //Left arrow key
    if(e.which == 65) leftKey = true;
    //Right arrow key
    if(e.which == 68) rightKey = true;

    var diagonals = Vertical && Horizontal;
    if(downKey)
    { 
        Vertical = true;
        moveY -= diagonals ? MoveSpeed * sqrt2over2: MoveSpeed;
    }
    if(upKey)
    {
        Vertical = true;
        moveY += diagonals ? MoveSpeed * sqrt2over2: MoveSpeed;
    }
    if(rightKey)
    {
        Horizontal = true;
        moveX -= diagonals ? MoveSpeed * sqrt2over2: MoveSpeed;
    }
    if(leftKey)
    {
        Horizontal = true;
        moveX += diagonals ? MoveSpeed * sqrt2over2: MoveSpeed;
    }   
}

I need to have this work so that the screen doesn't pause at all when you press another direction or multiple directions. Currently there is a bit of a pause. Is there a setting to turn off this pause or is there another approach to pooling and responding to input which circumvents this dilemma?

score 2 · Accepted Answer · edited May 23 '17 at 12:19

2

I think the pause is due to key repeat rate. Take a look at this question / answers: remove key press delay in javascript

edited May 23 '17 at 12:19

Community

1
1

answered Sep 12 '11 at 04:23

sinelaw

16,205
3
49
80

score 1 · Answer 2 · answered Sep 12 '11 at 04:26

1

The problem is that you're using the operating system's key repeat as the 'tick' for moving. Instead of this you should use setInterval to create your own tick for moving, and then monitor keydown / keyup to change the direction of movement.

answered Sep 12 '11 at 04:26

bradley.ayers

37,165
14
93
99

How to get input from javascript without stutters between changing keys pressed

2 Answers2