How does Google Body load so fast?

Question

http://bodybrowser.googlelabs.com/

I know the source of my data, and even for real-time use, these meshes and textures often amount to hundreds of KB or even several MB each. Even with low resolution, it’s hard to understand how they can make it work for 1 s of loading ... I see some evidence of texture streaming if I immediately switch to another level, but to get even the time-loaded polygons is impressive.

How did they achieve this - ultra-low policies or just a very smart progressive download?

Answer 1

Some of Google’s tricks for quick start-up Body loading and overall performance are delta data compression, limiting numerical precision and texture atlases.

Cache headers help reduce this on subsequent visits.

For rendering speed (which affects load time, since it is at the same time), they also perform other stitching techniques, such as aggregating a vertex array, interleaving a vertex array, and sorting GL states.

Google I / O 2011: WebGL methods and performance: http://www.youtube.com/watch?v=rfQ8rKGTVlg

Presentation of Google Body at Camp No. 3 WebGL: http://www.youtube.com/watch?v=vsHHNClzJPg

Answer 2

All manipulating the cache of magic. I also do this in my game to speed up the loading of the model, texture and sound. Their cache control header:

Cache-Control:public, max-age=31536000

Tells the browser to save all data for a whole year without re-checking the cache (there will not even be one transition between the browser and server until the full passage of the year).

It took me about 50 minutes for my cold cache broadband network to download 23.89 mb, so I can publish a Chrome HAR file so you can see all my downloads in detail.