Asset Thumbnail Cache

[Galaco]

Loading all materials and models fully on every engine load, or even directory open will be very unperformant.

Write a thumbnail cache mechanism to store thumbnail image in the assetviewer.

Requirements:

• Cache should be 1 file at most per directory
• Minimal GPU resource usage - texture atlas based?
• Cache should be invalidatable/rebuildable

• Design a cache format
• Implement cache read
• Implement cache write
• Load single thumbnail from cache