I have some code based on the 3d perspective projection formula I found on wiki.
It works great... mostly :)
I recently started making the code do z ordering/culling... but I was getting weird results. After a lot of debugging I came to realise my formula for working out the zorder value is wrong.
So... I created this in sketchup.
The params I use to do the projection are CoordinateToProject, CameraPosition, CameraRotation, ViewerPosition.
1) What exactly is the formula I need calculate the zorder value/distance, please?
2) Why does my code not support -Z? Is it a most likely a bug in my code or a limitation of the formula?
Edit: I am now happy with the answer to number 2. I just need to know how to calculate the z order.... any links/help would be appreciated!!!!