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  LWJGL camera zooming?  (Read 730 times)
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Offline EliwoodL

Senior Newbie





« Posted 2013-07-08 15:52:54 »

So I have a float value called zoom.  Zoom can be anywhere between 0.0125 and 1, with 1 being fully zoomed out, and 0.0125 being approximately 80 times zoomed in.

I'm attempting to change this value using the mouse scroll wheel, but I'm not sure how I would want to get a smooth zoom.  Would I repeatedly add (0.0125 * scroll wheel change) to the zoom value?

Or would I perhaps multiply zoom by something like 1.05?

Essentially, the question is, how would I go about creating a smooth zooming "range"?
Offline PaidGEEK

Senior Member


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« Reply #1 - Posted 2013-07-08 16:07:59 »

Simple linear interpolation should do the trick:
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int wheel = Mouse.getDWheel();
if (wheel != 0) {
   targetZoom += 0.05f * wheel;
   targetZoom = clamp(targetZoom, 0.0125f, 1f); //clamp(x,min,max)
}
float t = 0.02f; //speed
camera.setZoom(camera.getZoom() + t * (targetZoom - camera.getZoom()));

Improvisational programmer.
Offline EliwoodL

Senior Newbie





« Reply #2 - Posted 2013-07-08 16:25:04 »

Linear interpolation, huh?  I'll keep that in mind, thanks.

EDIT: nevermind, figured that one out.

However, my question now is:  Mouse.getDWheel() is returning an int of 120.  Is the 120 a universal value across all mouses, or do I need to create something to accomodate a change in that value?
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Offline PaidGEEK

Senior Member


Medals: 5
Projects: 3


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« Reply #3 - Posted 2013-07-08 16:39:16 »

Mouse.getDWheel() should return negative, 0 or positive number. So just change that to -1, 0 or 1 using IF's.

Improvisational programmer.
Offline EliwoodL

Senior Newbie





« Reply #4 - Posted 2013-07-08 18:13:01 »

Aha, yeah, I figured something like that would be needed.  Thanks for the help, though!  It really did help a lot.
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