Lighting Engine distorting/crumpling rigged models

[nteragadev]

It's more glaring in my custom mesh but you can also see it in the included "crawler" mesh, Top is "textured" and bottom are "textured + lighting". When the lighting is turned on, the mesh distorts. Both of these examples are from the same exact view.

 

In the crawler you can see the neck silhouette has altered.

In mine...well it speaks for itself. Unusable levels of distortion.

I also tested the fpsautopistol mesh and it too distorts, though the distortions are not detrimental to its appearance.

 

The distortions carry over straight into the game itself.

 

I'm using the LWdemo in hopes of determining whether to purchase. If this is a demo-only issue, I would like to know. If not, I am concerned since I am a modeler/texture artist.

 

[nteragadev]

Okay, looking into it further, it is directly related to materials with animations included. On the left is my mesh with the crawler mat applied to the chest and neck. On the right is no mat. What's interesting is even though the mat is different the distortion points are identical.

 

Not pictured but relevant, the test I did with a static material, looked the same as no material as far as distortions go.

 

 

[Josh]

That is rather odd. Looks like a small inaccuracy in the weighting equation. We did recently modify the FBX importer to deal with something like this, but I can't promise this exact issue was fixed without seeing your FBX models.

[nteragadev]

I used a blender exporter that exports straight to leadwerks asset formats, mdls and mats. I can try the FBX exporter but I figured a direct export would be the ideal. If FBX works better and avoids this issue I will happily switch.

 

It's worth noting that some distortion occurs even with included assets like the crawler and fpsautopistol models.

[Josh]

I am guessing it's an issue of the bone weights not being normalized in the vertex shader. If you can post a model that easily shows the problem I will test it.

[nteragadev]

I've PMed you the link. The problem is most obvious around the hands and the chest and neck.

[Josh]

Thanks for pointing that out. A small change in the shader fixed it. In the file "Shaders/Model/Animated/diffuse.shader" find this block of code in the vertex source:

    mat4 animmatrix = bone.matrix[vertex_boneindices[0]] * vertex_boneweights[0];
   animmatrix += bone.matrix[vertex_boneindices[1]] * vertex_boneweights[1];
   animmatrix += bone.matrix[vertex_boneindices[2]] * vertex_boneweights[2];
   animmatrix += bone.matrix[vertex_boneindices[3]] * vertex_boneweights[3];

 

Replace it with this:

    vec4 wt = vertex_boneweights;
   float m = wt[0]+wt[1]+wt[2]+wt[3];
   wt[0]/=m; wt[1]/=m; wt[2]/=m; wt[3]/=m;

   mat4 animmatrix = bone.matrix[vertex_boneindices[0]] * wt[0];
   animmatrix += bone.matrix[vertex_boneindices[1]] * wt[1];
   animmatrix += bone.matrix[vertex_boneindices[2]] * wt[2];
   animmatrix += bone.matrix[vertex_boneindices[3]] * wt[3];

 

Before:

 

After:

 

This fix will make it into the official build in the next update.

[nteragadev]

Awesome! That's wonderful. Thank you very much sir!

 

Bonus question, will the problem crop back up if I have to use a different shader?

[Josh]

There are three animated shaders. You must make this fix in all three. Or wait for the next update to go out, and it will be fixed for you.