A sprite sorting issue?

[KrevRenko]

This topic is an evolution of a discussion @ Tycoonez.com:munity.

It seems there are more issues with the sprite sorter than just the stations and the bridges. It has been observed that there are issues with parts of train catenary disappearing/being drawn over sprites when a train passes on the track. I include evidence in the attachments. Is this known or has it just been overlooked? I guess it would be solved when the already discussed things are solved. Now am I right?

The pix are taken from a48(I suppose, if not, I'll correct myself). It is shown with different train sets(CSDset trains and traction and also original trains with MB traction) so this is probably not a GRF problem, more likely a sprite sorting problem.

[KrevRenko]

Sorry for the double post, this is meant to be a (bump) in the first place.

I've read somewhere @ one of the older threads here on the forums that the sprite sorter works by judging the center pixel of the bounding-boxes. Now, I don't know how complex this is, but as long as everything is somehow stuck to the ground(RVs, trains and buildings comply), I mean if there are no objects hanging from wires or so, then probably the lower left corner of the bounding box would be a better place for measuring. If that corner is lower on-screen, it means closer in perspective. Please correct me if I'm wrong in any way.

[Patchman]

No, it doesn't work that way, and it's a whole lot more complicated.

One big problem is that the bounding boxes can only be oriented in the X and Y directions (along a grid line), which causes the boxes for vehicles moving horizontally to be either too wide or not long enough. This cannot be fixed without rewriting the whole sprite collecting and sorting system, including assigning bounding boxes to vehicles. Don't hold your breath for that to happen.

[KrevRenko]

I thought that vehicle sprites had their bounding boxes that move along with them. If I got this right, they don't, right? Thx for the explanation.


----------------------------------------------------
This happens when a person with no practice at doing something tries to think about it.

[Patchman]

No, the bounding boxes move, but they're much smaller than the vehicle in the hor and ver directions. This leads to some unavoidable clipping errors.