improve round line joins for semi-transparent lines #1359
Merged
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
ansis
added a commit
to mapbox/mapbox-gl-test-suite
that referenced
this pull request
Jul 6, 2015
ansis
added a commit
to mapbox/mapbox-gl-native
that referenced
this pull request
Jul 6, 2015
mapbox/mapbox-gl-js#1359 Round line joins used to be drawn by adding a semicircle cap to the end of each segment. This looked fine for opaque lines not for semi-transparent lines. This changes the triangulation so that round line joins don't overlap with segments. The gap between segments is filled with small triangles that look like pie slices. The edge of the round linejoin is made up of many short straight lines that look round at the sizes we draw lines. Since sharp angles are infrequent, this does not significantly affect the total number of triangles created. Joins for angles that are really sharp are still drawn with overlap.
|
Looks good. It'd be cool to get tests that check the created buffers for a few edge cases and make sure that the algorithm in native produces the same results. |
|
Get it? Edge cases... |
|
Nice! |
Round line joins used to be drawn by adding a semicircle cap to the end of each segment. This looked fine for opaque lines not for semi-transparent lines. This changes the triangulation so that round line joins don't overlap with segments. The gap between segments is filled with small triangles that look like pie slices. The edge of the round linejoin is made up of many short straight lines that look round at the sizes we draw lines. Since sharp angles are infrequent, this does not significantly affect the total number of triangles created. Joins for angles that are really sharp are still drawn with overlap.
|
I added an extra render test but I'll skip testing buffers directly for now. |
ansis
added a commit
to mapbox/mapbox-gl-native
that referenced
this pull request
Jul 8, 2015
mapbox/mapbox-gl-js#1359 Round line joins used to be drawn by adding a semicircle cap to the end of each segment. This looked fine for opaque lines not for semi-transparent lines. This changes the triangulation so that round line joins don't overlap with segments. The gap between segments is filled with small triangles that look like pie slices. The edge of the round linejoin is made up of many short straight lines that look round at the sizes we draw lines. Since sharp angles are infrequent, this does not significantly affect the total number of triangles created. Joins for angles that are really sharp are still drawn with overlap.
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.
Round line joins used to be drawn by adding a semicircle cap to the end of each segment. This looked fine for opaque lines not for semi-transparent lines.
This changes the triangulation so that round line joins don't overlap with segments. The gap between segments is filled with small triangles that look like pie slices. The edge of the round linejoin is made up of many short straight lines that look round at the sizes we draw lines.
Since sharp angles are infrequent, this does not significantly affect the total number of triangles created.
Joins for angles that are really sharp are still drawn with overlap.
@kkaefer want to review?