Line disappers if you draw it for too long

[nm17]

Lorien version: 78c06a8 or release v0.2.0

OS/device including version:
KDE neon Testing Edition 20.04
Nvidia driver: 460.80

Issue description:
If you draw for long enough with pressed left mouse button the line you drew disappears.

Demonstration here: https://www.youtube.com/watch?v=LDZc1JiYunI

--- Debugging process started ---
Godot Engine v3.3.2.stable.official - https://godotengine.org
OpenGL ES 2.0 Renderer: GeForce GTX 1650/PCIe/SSE2
OpenGL ES Batching: ON
 
Loading i18n file: res://Assets/I18n/en.txt
Loading i18n file: res://Assets/I18n/it.txt
Loading i18n file: res://Assets/I18n/es.txt
Loading i18n file: res://Assets/I18n/de.txt
Stroke points: 1571 (517 removed by optimizer)
Stroke points: 1592 (739 removed by optimizer)
Stroke points: 19 (7 removed by optimizer)
Stroke points: 17 (8 removed by optimizer)
Stroke points: 1237 (918 removed by optimizer)

Steps to reproduce:
Just draw a line for long enough and it will disappear

[nm17]

Found the cause for this bug:

W 0:00:12.398   _prefill_polygon: poly has too many indices to draw, increase batch buffer size
  <C++ Source>  ./drivers/gles_common/rasterizer_canvas_batcher.h:1628 @ _prefill_polygon()

Increasing the batch buffer in project settings seems to solve this problem somewhat, but it still deletes very large lines.

[mbrlabs]

Thanks for the report. Yeah, that's a Godot limitation. There is an easy fix though: if a certain length is reached (say 1000 points per brush stroke) we can finish the current stroke and immediately start a new one, so it looks like one continous line.

[mbrlabs]

Fixed in bdf7eca