Add shadows property to Cesium3DTileset

[lilleyse]

For #3241

Similar to #4341, we should support a shadows property inside Cesium3DTileset, Batched3DModel3DTileContent, and Instanced3DModel3DTileContent. PointCloud3DTileContent is more involved so that should be held off for now.

@sumitshyamsukha Let's work on this one tomorrow.

[pjcozzi]

This is for per-feature shadows, right? Although I was the one who suggested this, I would hold off until we have enough interest since this comes with a high memory overhead. I would not use this as a beginner 3D Tiles issue. Please check the roadmap for others and let me know if you need input.

[lilleyse]

No this is for the entire tileset.

[pjcozzi]

Ah, +1 from me.

[lilleyse]

@sumitshyamsukha #4348 is merged so you should be able to finish your PR when you pull the latest 3d-tiles changes. One more thing to address is being able to set the shadows dynamically rather than just at creation time. To do that, in Batched3DModel3DTileContent.update you can set the model's shadows to equal the tileset's shadows. In Instanced3DModel3DTileContent.update you can set the ModelInstanceCollection's shadows to the tileset's shadows.

[rammy4real]

hello lilleyse . good day. hope you are doing great sir. i would love to contribute to this. just to let you that i am a starterwith the following knowledge level
html: intermediate
css:intermediate
javascript: basic/beginner
java: basic/beginner
really do love to be part of your team. I promise to give my best and my all .
thank you sir.
rammy4real@gmail.com

[pjcozzi]

@lilleyse OK to close this given #4386?

@rammy4real thanks for your interest in contributing to Cesium. A great place to start is the Contributor's Guide.

[lilleyse]

@lilleyse OK to close this given #4386?

Yup, closed.