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3D object movement with mouse

General and Gameplay Programming Programming

Started by JuliusDegutis March 07, 2014 08:45 AM

4 comments, last by Stainless 10 years, 1 month ago

JuliusDegutis

377

Author

March 07, 2014 08:45 AM

Hello,

I started to make 3D game. I have free camera (can move anywhere, look everywhere, but not roll), and I have objects. I want to move objects with mouse. Objects Y coordinates I changing with mouse wheel. So what I just need, that mouse X and Y screen position (or delta position) move object on X and Z axis.

If my camera would be locked, then objectPosition+=mouseDelta would work something like what I want, but problem is what I don't have locked camera. But I have angle on Y axis rotation, so maybe that could help?

I'm using XNA, if that means anything

Ashaman73

13,718

March 07, 2014 09:27 AM

Get the up, right and lookat vector of the camera and tanslate the object along these axis (you move it in camera space), eg


objectPosition += right * mouseDeltaX + up * mouseDeltaY + lookat *mouseDeltaZ

(mouseDeltaZ could be the mousewheel movement)

For rotation take a look at arc-ball rotation.

Ashaman

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Stainless

1,875

March 07, 2014 10:31 AM

What I generally do is use the camera forward vector as a ray.

Intersect this ray with the ground plane, and move the selected object to this point.

You can see this in action here

Stainless

1,875

March 07, 2014 10:34 AM

Sorry not the camera forward vector, that's rubbish.

The vector from the eye through the mouse point, the same ray you use to pick the object.

JuliusDegutis

377

Author

March 07, 2014 12:56 PM

What I generally do is use the camera forward vector as a ray.

Intersect this ray with the ground plane, and move the selected object to this point.

You can see this in action here ...

And if I want move Up or Down, I just change Plane position? Looks nice, now just need to get Plane