arcball | Arcball Rotation Control | Game Engine library

i implement arcball with an object from .obj file in the center when i try to implement lighting, the object show strange behaviour

when i turn the object slightly, the object deconstruct and suddenly show the back side

this behaviour doesn's come up until i implement lighting based on this How to correctly add a light to make object get a better view with pygame and pyopengl

this is what i do regarding the lighting impelementation

I'm currently working on a STL file viewer. This one use an Arcball camera :

To provide more features on this viewer (which can handle more than one object) I would like to implement a click select. To achieve it, I have used picking(Pseudo code I have used)

At this time, my code to check for a any object 3D between 2 points works. However the conversion of mouse position to a correct set of vector is far away from working:

I'm trying to get the coordinates (x,y) of the grid (z = 0) using only the cursor coordinates. After a long search I found this way to do that using the glm::unproject.

First I'm getting the cursor coordinates using the callback:

I'm trying to show a 3D image (a sphere) with a texture that contains some information. I need to rotate and zoom in/out the image.

I just came up using glumply and I saw some examples that are very helpful (especially the Earth rendering example at https://github.com/glumpy/glumpy/blob/master/examples/earth.py).

However, so far I haven't been able to find any example at all that zooms in/out the image. Does anybody know whether that's possible or not? I'm starting to think that it is not possible, but that's somehow hard to believe. I would really appreciate any example of how to do it (or somebody who knows about it telling me that it's impossible). I just discovered glumpy yesterday night, so the more complete the example, the better.

Thanks a lot!

EDIT: As far as I have seen, both the Trackball and Arcball classes (which I use for the 3D sphere) have an on_mouse_scroll method which should already zoom in/out when the mouse wheel is turned. However, that method is never called when I turn the wheel. I'm not sure whether this has something to do with a message I get in the console when I execute the program:

I am using legacy OpenGL to draw a mesh. I am now trying to implement an arcball class to rotate the object with the mouse. However, when i move the mouse, the object either doesn't rotate or rotates by way too big an angle.

This is the method that is called when the mouse is clicked:

I am following this tutorial for arcball navigation in 3d:

https://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_Arcball

I managed to perform all the steps and the navigation works but I cant seem to comprehend last step in tutorial:

An extra trick is converting the rotation axis from camera coordinates to object coordinates. It's useful when the camera and object are placed differently. For instace, if you rotate the object by 90° on the Y axis ("turn its head" to the right), then perform a vertical move with your mouse, you make a rotation on the camera X axis, but it should become a rotation on the Z axis (plane barrel roll) for the object. By converting the axis in object coordinates, the rotation will respect that the user work in camera coordinates (WYSIWYG). To transform from camera to object coordinates, we take the inverse of the MV matrix (from the MVP matrix triplet).

The problem is that when i turn the model in the first step axis of rotation transform as well and they are not aligned with my "camera view". Of course I would like to keep my rotation axes always aligned with my camera view.

Can someone please give me an advice how to tackle it? In the tutorial there is a code but not much of explanation on what it is actually doing plus I only speak Python.

Thank you, Jacob

My code:

I am trying to figure out exactly how lookAt and perspective functions work.

I would like to change the value of glm::lookAt (in particular the z value of the camera position) and I have noticed that If that value is different from the value of near plane in glm::perspective it breaks my object (it looks anormal). Then, I do not know if my problem is related to the arcball (but I don't think so since the problem appears also before moving the object) or to the fact that for some reason I should use the same value for the camera position (z value) in the lookAt function and in the near plane in the perspective function.

Any suggestions?

I took the implementation of the arcball from https://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_Arcball

Main.cpp:

I'm confused as to why one of these would work and the other would not. I'm trying to enable switching of camera controllers, in both cases the (mostly) copy constructor succeeds, the first branch is segfaulting on the delete though

I am trying to change the camera view with mouse movement and want the camera to move around the origin in an arcball fashion without going under the scene; so sort of a dome-like view.

The following works satisfactorily for getting the eye coordinates and making this half-arcball view. I hardcoded a condition in order that I would not be able to view underneath the scene. The consequence of this condition is that instead of going under the scene, the camera will zoom into the center instead. I can't wrap my mind around how to impede the camera from doing this 'zoom'. When I get to the lowest part of the dome view, I'd like to only be able to move left or right. Distance is constant. Any guidance?