A pure Graphics 2 '3D' demo in progress

Solar2D Advanced Graphics
#21

I think I have it, it only really fails on large polygons so I’m going to sub diving the one closest to the camera and with a focus of 2, which yeah is a different way of doing field of view, it looks like it will work for all cases.

The stretching there an extreme case and it does warp horizontally as well, its just there the y value has shot to infinity so it gets pulled down a lot more than it should. Corona was saying it was going 1 million pixels down at that point so the perspective has failed.

It looks and works much smoother in real life, will post a vid when I get it put together. Corona actually does a much better job than I would have thought it could though it seems to automatically limit itself to 30fps when I have 100+ polygons on screen. Though final won’t need anywhere near that many.

#22

Any time you get a massive value offscreen means the point was getting dangerously close to the Z == 0 plane.

In the past another ‘solution’ (which produces its own visual artifacts) was to do a test on points that were too close and if so, simply move the individual points to a safe Z value. It goes wrong if more than 2 points per quad have this happen (the quad collapses onto itself, but to be honest if more than 2 points need this, you might actually be able to cull it entirely), and if this happens at all, chances are the perspective distortion will not match up at the edges (a very Corona-only error, due to them adding perspective automatically).

Either way you are trading 1 set of mistakes for another, but ridiculously large polygons might not be a problem - it really depends on how they get drawn by the GPU, and I have no idea how good the culling is and in fact it might vary from device to device (or rather, GPU chipset to chipset) - my advice in general would be to try to avoid if possible, simply because the worst that can happen is you save nothing, but it *might* be beneficial :slight_smile:

Good luck with this whatever it is - looks like a proper 3D racing game?

#23

I should point out if you are planning on having curves or twists (IE so the corners are not co-planar, or the opposite edges are not parallel) then the image perspective *will* go wrong due to how Corona calculates the perspective to use. Exactly how badly it goes wrong depends on the user case, but I just thought I’d mention it - forewarned is forearmed so to speak.

#24

Yeah its going to be a racing game, or at least the demo I’m writing is, probably…

Im not sure what you mean about the perspective going wrong. Each tile is going to be 256 x 256 and any corners will be a part of the texture. So 4 square tiles would be used to produce a 90 degree turn.

Are you saying this won’t work?

#25

Nope, that’ll work just fine.

From your screenshots I wasn’t sure if you were using some sort of spline-based routine to generate the overall shape of the track, and I was referring to that. As you aren’t doing it that way, you don’t need to worry :slight_smile:

#26

Ah cool. I was worrying it was going to be for nothing!

The idea is to designs a set number of pieces of track, assign collision walls to the segments and run the game in 2D through the physics engine.

Then the camera is set to follow the car and just reads the positional information from the 2D track.

Im doing a lot of the ground work up front for the game so the engine is progressing slower than it should be. But now I have it so you can have unlimited cameras and screens. If it wasn’t for the hit to the cpu I could do a rear view mirror.

How is yours coming it seemed quite far along a few weeks ago, its what got me back into Corona after a lengthy pause.

#27

Ah nice - yeah you could make the game run purely in 2D top-down first (likely what you are doing). Then converting to 3D visually would be relatively simple.

My stuff I haven’t touch in nearly 2 weeks. I was on holiday a week and came back to urgent deadlines so I’ve had no free time - which isn’t great as the compo deadline is coming up fast and I need to finish off my entries.