ZGameEditor forum

Hello everybody!

I'm a little confused about screen dimensions in ZGE.
When I moved a 2d bitmap (so, I changed the Position.X and Y of this model) in my first test program with the default settings, the left and right edge of the screen can be found at -5 and 5 values, while top and bottom are at -3 and 3.
But why? Why not 0 and 800, and 0 and 600? Is there a function to get the screen coordinates? And what if I set a smaller or greater screen resolution? The -5,5 and -3,3 values are constant even in this case?

Hi Tomi,

Tomi wrote: ↑Tue May 21, 2024 4:11 pmWhen I moved a 2d bitmap (so, I changed the Position.X and Y of this model) in my first test program with the default settings, the left and right edge of the screen can be found at -5 and 5 values, while top and bottom are at -3 and 3.

By default ZGameEditor uses a camera with a perspective projection and a vertical field-of-view of 45 degrees positioned at coordinate 0,0,10.



When using a 3D / perspective camera the edge of the screen is dependent on how far your object is away from the camera.

Tomi wrote: ↑Tue May 21, 2024 4:11 pmWhy not 0 and 800, and 0 and 600? Is there a function to get the screen coordinates?

If you want to have a coordinate system that matches your viewport, i'd recommend using a camera with a orthographic projection instead. Attached is a basic example.

K

A-ha! Thanks, Kjell; so is ZGE basically uses 3D projection, even in the case of a 2d program? But I will look your attached example program...

Hi Tomi,

Tomi wrote: ↑Wed May 22, 2024 2:09 pmso is ZGE basically uses 3D projection, even in the case of a 2d program?

No, you don't have to use a 3D projection if you don't want to. Simply add a Camera component to your project and configure it to your needs .. below is the exact same scene viewed using 3 different camera configurations.







K

Thanks again, Kjell!
I started to understand it based on your attached images.
But returning to your previous words:
"When using a 3D / perspective camera the edge of the screen is dependent on how far your object is away from the camera."
Okay, but in this case how can I get the exact screen dimensions? Is there such a function that give those values in different distances from the camera? App.ViewportWidth and App.ViewportHeight?

Hi Tomi,

It's simple Pythagoras theorem

So .. by default the camera is positioned at 0,0,10 and uses a perspective projection with a FOV of 45. When you create a diagram of that situation viewed from the side ( over the x-axis ) it looks something like this:



You can find the vertical "screen edge" for z-coordinate = 0 using the following calculation:



K

hi Kjell,

could you upload the .zgeprojet of the isometric example?

Kjell wrote: ↑Thu May 23, 2024 9:41 am

Hi LsJack,

LsJack wrote: ↑Thu May 23, 2024 6:35 pmcould you upload the .zgeprojet of the isometric example?

Sure, i swapped out the model & textures with procedural alternatives for filesize & copyright reasons ( and added a bit of movement ) .. but aside from that it's the same thing.

K