Tested locally by hacking gltf-viewer on Android, added the following
lines to MainActivity:
```kotlin
for (mat in modelViewer.asset!!.materialInstances) {
Log.d("gltf-viewer", mat.name)
}
```
Fulfills a request from tirichards@.
This is similar in some ways to dynamic backface culling but simpler
because there is no interaction with double-sided lighting.
For reference, dynamic backface culling was implemented with #1936, #1877, #1641.
Previously we used the <T=float> template instantiation of setParameter
when the client specified FLOAT4. This resulted in the lower layer
adding needless padding, thus causing a buffer overflow.
Moreover the JNI code for this was somewhat cryptic because it casted an
enum value to an int, then added 1 to compute the size. We now use
a switch statement to improve readability.
This issue was discovered (and the fix was verified) with the upcoming
Android port of the bloom demo.
This replaces the previous "curvature to roughness" method. Both are related
and rely on the screen space variance of geometric normals but this new
solution offers more control (the screen space variance and the clamping
threshold can be controlled).
* MaterialInstance now has setMaskThreshold for convenience.
* Materials now support dynamic doubleSided property.
This does not change the format of material packages because they
already have both getDoubleSided() and getDoubleSidedSet().
The only way in which this change could impact existing applications is
that materials that explicity set doubleSided to "false" will now
respect the material's culling mode, rather than forcing it to NONE.
Fixes gltf_viewer with littlest_tokyo in ubershader mode.
Fixes#963.
* JNI for dynamic material properties.
* Add underscore prefix to internal material params.
* Remove un-needed mat info field.
