Vertex Normals Issue

[Kyrah Abattoir]

32 minutes ago, Beev Fallen said:

i actually have no right words about the job you guys, @Beq Janus , @polysail , have done here.
it's mindblowing to me, the final result. IT IS MIND-BLOW-ING.
i have no idea how this wasn't seen for ages. the SL is going to change when you release this.
thank you guys for your brilliant investigation and time spent and all that work.

Problems like this can be hard to diagnose, it all depends on whether you "think" the behavior is correct, or incorrect, the normal map demonstration highlights "the consequences" of something that might otherwise not be obvious to the naked eye.

[Polymath Snuggler]

Thank you Beev~  it was a lot of effort ( mostly on Beq's part ) I  managed to erroneously (partially?) convince Beq pretty much every step of the code was wrong before we managed to convince ourselves that it actually wasn't.

But the change won't be that ground-breaking for SL.  The average mesh in SL fits more or less just fine in a cube, or a half-cube-volume.  (Think dresses, beds, sofas, small bushes , rocks etc).  The object ratio is only 2-5 off of a perfect cube.  So the tangents would be off, yes, and look sliiiightly weird, but ~ not really in a manner that would be immediately noticeable.

That being said ~ I am immensely pleased it wasn't just 'in my head' that something has been 'off' all these years ~ As I said in my first ( very incorrect ) JIRA report ~ I've been chasing this bug, in some form or another ~ for the last 5 years ~ so, it's a personal victory for me, and it will help make people's lives in SL just a little bit better ~ which is nice!  So thank you again @ZedConroy for giving me the point in the correct direction that I needed.   I was very much "interested".

 

One last thing: Scale Matrices Suck.  I routinely get them wrong...Thankfully Beq doesn't.  😆

Edited July 7, 2020 by polysail

[Beev Fallen]

23 minutes ago, polysail said:

But the change won't be that ground-breaking for SL. 

i actually see much more 'expected' kind of behaviour and definition on normal maps in the examples that Beq provided... so we will see

here i cropped the regular cube prim part from the Beq's screenshot, to me it looks like heaven with fixed version:
 

Edited July 7, 2020 by Beev Fallen
added an image

[Ana Stubbs]

When this gets released, I for one will be digging back through my inventory to check some old projects that never quite looked right.

Also, thanks to @Beq Janus for the very interesting explanation. I'll be studying computer graphics in the autumn, so it's nice to hear the more mathsy details.

[Wulfie Reanimator]

5 minutes ago, Ana Stubbs said:

I'll be studying computer graphics

I'd recommend looking up things like line-draw algorithms, rasterisation, and matrices (singular: matrix -- related to homogeneous coordinates) which you'll need to get things drawn on the screen correctly.

This is an amazing resource: https://www.scratchapixel.com/

Edited July 7, 2020 by Wulfie Reanimator

[Ana Stubbs]

Just now, Wulfie Reanimator said:

I'd recommend looking up things like line-draw algorithms, and matrices (singular: matrix -- related to homogeneous coordinates) which you'll need to get things drawn on the screen correctly.

Thanks! I already have a physics degree, so linear algebra is my jam. I'm really looking forward to it.