MaxCoderz

Hi guys,

Just thought id let you know that i have uploaded a project to
ticalc.org today. It is a 3D engine for the TI-83+ series calculators.

The program is a 3D model viewer that enables the user to view and
interact with a 3D model in real-time. Note that it renders
flat pattern-shaded polygons. Also included is a utility to convert
Wavefront OBJ models to .8xp programs for use with this
viewer.

It is written in z80 assembly and a 15MHz calculator is recommended.

It is in beta testing so there could be problems. Please report any bugs
if you find any.

Here is a link: http://www.ticalc.org/archives/files/fi ... 45097.html

Also here are some screenies.




Id appreciate feedback if anyone has some.

Enjoy.

Very impressive work - I lack the relevant equipment to install it on a calculator so I played around in an emulator and it seems to work very well indeed.

Do you have any plans for what you'll work on adding next?

Hi Ben, Thanks for the quick reply! .

I need to correct the back-face culling for a start and add polygon clipping i think. Plus i need reorganise the memory structure a little.

For now i might just have a go at making some 3D models to test with .

I see - how have you implemented the backface culling at the moment?

The BFC is very basic, at present i do it after transforming but before projecting using:

; bfc = (x0-x1)*(y2-y1)-(y0-y1)*(x2-x1)

Where the sign is taken to determine which direction the polygon is facing. The error involved means that faces on the boundary between facing and not-facing are sometimes confused.

Ill need to implement it properly in the future.

I gather it's the "before projecting" that is causing the error? Ah well, I look forwards to seeing where you take this next.

Hmm why is the X-Wing model not included? !!! Awesome work.

Ill tidy up the xwing model and release if you like.

In the meantime i have been experimenting with basic lighting effects:


Here is a better screenshot of whats going on (i hope):


Also here is the xwing:

As usual, Pat, you never cease to amaze! This looks just amazing!

The slower-spinning cube does indeed make it more clear what you're doing--and it looks great! Does that work with multiple objects? Does it perform well?

Also, that X-Wing looks great

I do need to fully implement it so that it is based on an idependant world position as opposed to the camera (was a quick hax), but it supports all objects in the 'world' without any code changes.

That's pretty impressive. What about multiple light-sources?

Well technically it would be possible, but i would have to properly implement lighting as opposed to this hack. That being said, per model lights should be easy too.

Also i have added polygon clipping, but only in 2D which means that any polygons that have a vertex behind the near plane (z=0) will be culled and not clipped as demonstrated in this screenie:



Still that only typically happens when you are 'in the middle' of a model so in most cases it should be acceptable.

Very, very nice work! I really like the lighting effects.
Good to see someone is still working on a 3D engine

Oh wow hi yhean!! Long time no see, i hope you're doing well!

Thanks for your kind comments, i remember your 3D engine (juha3D?), it was very impressive and a large inspiration for my interest in calc 3D .

Good to see you .