Bring back natively un-patterned lines (Fix parts of lines disappearing with large coordinates)

[ffreyer]

Description

This restores the init-time decision between having a line pattern texture or not, and replaces lastlength arrays with dummy data when they are not needed. This fixes an issue reported on Slack, where random segments of a line disappear:

using GLMakie, Dates
f,a,p = lines(Date(2000):Year(1):Date(2009), rand(10))

I didn't thoroughly think through the cause of this issue, but it's probably a Float32 precision issue with f_pattern_overwrite in process_pattern() in lines.geom. The dates convert to large numbers ~6e13. Without patterns, GLMakie skipped projections when calculating gl_last_length, so that they ended up with ~6f13 values too. With the pattern texture always given, the shader ended up mixing those values with pixel scale offsets, which are way below float precision. I assume that (or something similar) caused texture sampling to break.

Setting gl_last_length to NaN's, Inf's, zeros, etc fixes the issue. Skipping the pattern::Texture branches does too, and it should improve performance.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• Added an entry in CHANGELOG.md (for new features and breaking changes)
• Added or changed relevant sections in the documentation
• Added unit tests for new algorithms, conversion methods, etc.
• Added reference image tests for new plotting functions, recipes, visual options, etc.

[MakieBot]

Benchmark Results

SHA: 856c53952e202a756b9e4e6a0d5ea6d8d0b05143

Warning

These results are subject to substantial noise because GitHub's CI runs on shared machines that are not ideally suited for benchmarking.