CODEWITHSUNDEEP
javaopenglubuntufullscreenjogl
HahaHortness
HahaHortness

Reputation: 1628

Viewport seems to be slightly offscreen in fullscreen

In an OpenGL program I have a Camera object that sets up the projection matrix to be centered on a sprite. It worked fine until I went into fullscreen mode, there I noticed the object I focused on was off center. After messing around with my resolution I noticed that 4:3 resolutions don't have this problem(I was originally at 1680x1050) and then I found the following.

1280x1024: object is centered.
1280x960: object is centered.
1280x720: object is not centered and the entire viewport seems to have shifted left. That is, when I move my mouse left it seems to move off screen a few inches and there is a black region on the right of my screen where nothing is drawn and my mouse won't move into.

Has anyone had a problem like this? I'm on Ubuntu if that's significant.

Upvotes: 0

Views: 314

Answers (2)

Bahbar
Bahbar

Reputation: 18005

My guess would be that your monitor is connected through VGA, and is not correctly calibrated for that resolution. So the monitor shifts the display output.

Possible solutions include:

  • recalibrate your monitor (either automatically or manually, either from the monitor controls or the OS control, if available)
  • switch the connection to a digital one (say DVI or HDMI).

Upvotes: 0

Nicolas Lefebvre
Nicolas Lefebvre

Reputation: 4282

Are you accounting for the aspect ratio when setting up your projection matrix ?

This tutorial might be a useful read if not.

Here is my own version (in python but it should be trivial to translate to java) if having a code sample helps; initPerspectiveMatrix takes an aspect ratio, i.e. height/width.

def calcFrustumScale(fov):
    return (1.0 / np.tan(np.deg2rad(fov) / 2.0))

def initPerspectiveMatrix(aspectRatio = 1.0):
    scale = calcFrustumScale(60)
    ARscale = scale*aspectRatio
    near = 0.5
    far = 1000.0
    perspMx = np.array([[ARscale,  0.0 ,          0.0         ,            0.0         ],
                       [  0.0  , scale,          0.0         ,            0.0         ],
                       [  0.0  ,  0.0 , (near+far)/(near-far), (2*near*far)/(near-far)],
                       [  0.0  ,  0.0 ,         -1.0         ,            0.0         ]], dtype='float32')

Upvotes: 1

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