Propose a standard way to talk about the camera (etc) in SkCanvas:
- client provides 3 matrices: viewport, projection, camera
- canvas->concat(viewport * projection * camera * invert(viewport)
- camera and projection are taken straight from the textbook for 3D
- "viewport" means a matrix that transforms +-1 square about the origin
to the clients working canvas. A simple way to describe it is:
"specify the area-of-interest with a rectangle and z_scale"
Expose the ctm as a 44 from canvas for now. Likely we will add these
3 new matrices to canvas, and each may have a getter.
Bug: skia:
Change-Id: I6fa79c56956e060c17569848a81e13c13cb0981a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/264221
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
