Make shaders clamp perspective ratio to reasonable ranges. #6365
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This fixes issue #6363, but also guards against a class of bugs: We previously relied on the assumption that the perspective ratio was calculated with the same anchor point as the item we were drawing. If that assumption was violated, it was possible for overzoomed items far outside of the viewport to grow larger faster than they moved away from the viewport. They could eventually grow large enough to cover the viewport entirely, causing brief "flashes" during map animations. This commit does _not_ clamp the perspective ratios on the CPU side, to avoid extra work in the inner loop of very performance sensitive collision/projection code. On the collision side, anything far outside of the viewport should be collided/ignored anyway, and on the projection side, we have a filter requiring that the anchor of the label be within the viewport before the projection logic begins.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This fixes issue #6363, but also guards against a class of bugs:
We previously relied on the assumption that the perspective ratio was calculated with the same anchor point as the item we were drawing. If that assumption was violated, it was possible for overzoomed items far outside of the viewport to grow larger faster than they moved away from the viewport. They could eventually grow large enough to cover the viewport entirely, causing brief "flashes" during map animations.
This commit does not clamp the perspective ratios on the CPU side, to avoid extra work in the inner loop of very performance sensitive collision/projection code. On the collision side, anything far outside of the viewport should be collided/ignored anyway, and on the projection side, we have a filter requiring that the anchor of the label be within the viewport before the projection logic begins.
I tested manually against the repro case in #6363 and was unable to reproduce the flashing after applying the fix.
Benchmarks: https://bl.ocks.org/anonymous/raw/8dcdc2656bd3be7bbd24c9a69800b7a2/
/cc @jfirebaugh @ansis @malwoodsantoro