tree a607bfb27baa0f24fe3873e4c461866e6fa84c15
parent 98378352be5ef4a3dd26bff92abe9265c6dec6f3
author Jim Van Verth <jvanverth@google.com> 1620227491 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> 1620240686 +0000

Add basic D3D mipmap support.

This adds support for mipmap generation in the simplest case:
* power-of-two
* non-sRGB
* not BGR

The mipmaps are generated with a compute shader that reads from a SRV
of one miplevel and then writes to a UAV at miplevel+1. Miplevel+1 is
then transitioned to a resource state that can be read from, and the
process continues for miplevel+1 and miplevel+2, etc.

Change-Id: Id467d0e56d5408559d3cacec1514f1b43d76d640
Bug: skia:10446
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/392917
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>