TrackballCamera Zoom in/out with mousewheel #452
Description
Some people might find this useful : catching the mousewheel event to zoom in and out of pane. I do anyway, thought it could be interesting feature to add to the TrackballCamera.
(I'm a total noob at github, sorry if this is out of context...)
Here's a basic implementation I've used :
// need both for FF and Webkit - others I haven't tested
window.addEventListener('DOMMouseScroll', mousewheel, false);
window.addEventListener('mousewheel', mousewheel, false);
function mousewheel( event )
{
var amount = 100; // parameter
// get wheel direction
var d = ((typeof e.wheelDelta != "undefined")?(-e.wheelDelta):e.detail);
d = 100 * ((d>0)?1:-1);
// do calculations, I'm not using any three.js internal methods here, maybe there is a better way of doing this
// applies movement in the direction of (0,0,0), assuming this is where the camera is pointing
var cPos = camera.position;
var r = cPos.x*cPos.x + cPos.y*cPos.y;
var sqr = Math.sqrt(r);
var sqrZ = Math.sqrt(cPos.z*cPos.z + r);
var nx = cPos.x + ((r==0)?0:(d * cPos.x/sqr));
var ny = cPos.y + ((r==0)?0:(d * cPos.y/sqr));
var nz = cPos.z + ((sqrZ==0)?0:(d * cPos.z/sqrZ));
// verify we're applying valid numbers
if (isNaN(nx) || isNaN(ny) || isNaN(nz))
return;
cPos.x = nx;
cPos.y = ny;
cPos.z = nz;
}