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pixeljetstream / ldrawloader

ldraw file loader library
MIT License
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Parts can refer to other parts that are mirrored and it flips the faces resulting to inside out rendering #3

Closed mzwaal closed 10 months ago

mzwaal commented 1 year ago

In the official ldraw library, people mirror parts that they have already written via a matrix transformation. In those cases the winding is not flipped by ldrawloader.

Parts can refer to other parts a few levels deep, so this probably need to be fixed recursively.

A good example would be minifig arms

Great library by the way!

pixeljetstream commented 10 months ago

can you provide a sample ldraw scene for this problem? some level of winding changes are expected to be handled by the renderer / outside the library to allow instancing of the data.

https://github.com/pixeljetstream/ldrawloader_viewer I made this debugging tool public now and it does handle some winding changes through openGL at rendertime / testing matrix determinant.

mzwaal commented 10 months ago

Thanks, I will test the issues first with this viewer and let you know how it goes.

There were some other official parts that rendered in a sub optimal way and some that triggered the asserts. It might be useful to have a test application that tries to load each part of a given official library and logs the exceptions to see which parts fail.

I also had build such a loader btw, but yours has some nice surface optimizations so I decided to switch

mzwaal commented 10 months ago

I have checked my implementation and managed to fix it. Thanks!

I originally had implemented it like yours, but I thought it was wrong because of another issue and started to modify the ldrawloader which solved my issue for most cases but was kind of a hack.

In other words, my issue is solved and your reference implementation helped me and will help others in the future.