Transitioning to OpenGL

[Darylgolden]

Our current system of having Mobjects for 2 different renderers is unsustainable. While a metaclass approach as suggested in #1272 could work, I think we should still try to move to making OpenGL the default renderer sooner rather than later.

Some of the challenges in transitioning could be:

• Docs (OpenGL and rendered documentation #1214)
• Tests (probably not difficult to do)
• Difficulties in helping users transition (Strokes are not rendered in some installations of Manim using OpenGL renderer #1240 is a known problem of the OpenGL renderer with Intel integrated graphics, we need to find a fix or workaround)
• Making sure the features/fixes/enhancements to Cairo are ported over to OpenGL (Update: Mobjects are being moved over using the metaclass approach)

[MrDiver]

OpenGL rethinking the architecture (Maybe also deal with Cairo?)

This discussions seeks to find a proposable idea for a new rendering Architecture surrounding the OpenGL Renderer.

• As a first step i think we should find out what the current state of the renderer is in 3b1b/manim and make a sketch on how it currently works and what features are supported.
• Second step is to find out what we are lacking feature wise and how we might improve our own architecture or merge it with the state of 3b1b/manim
• Decide on what to do and file Issues corresponding to the proposed idea.

Related Issues and Ideas:

• DRAFT: remove all OpenGL<x> mobs and the ConvertToOpenGL metaclass. #2454
• POC: Implement Plugin using Hooks (with pluggy) #2635
• Created initial abstract renderers #2455
• Fix triangulation  3b1b/manim#1586
• Incorrect triangulation of polygons with many holes 3b1b/manim#1331

[MrDiver]

Rendering Curves with OpenGL

• https://www.codeproject.com/articles/226569/drawing-polylines-by-tessellation

• Nvidia GPU Gem3 Vector Art Ch.25

• Microsoft Rendering Bezier shapes

• Curvy Blues

• OpenGL vs Cairo Beziers

• Offset Beziers

• Funny Nvidia Forum Discussion

• Vase Renderer

• OpenGL 4.0 Rasterization of Parametric curves using Tesselation

• BlogPost Polyline

• Git List of Resources

• GPU Path Rendering

• Path Rendering can be done in GL Only?

• RA VG - Random Access Vector Graphics

• RAVG - Website

The current best solution for rendering curves might be to implement nv_path_rendering in opengl only. Im not quite sure how much that would improve our situation but it might be worth a try.

Or doing something like VASEr which is kind of what we do now using earclip.

[MrDiver]

• Created initial abstract renderers #2455
  Useful information