ManimCommunity / ManimCommunity/manim

`MObjects` dependent on `OpenGLSurface` behave differently in Cairo and OpenGL

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issue:bug
Dominant language
Python
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Description

## Description of bug / unexpected behavior

When doing 3D animations with `Dot3D` or other 3D mobjects based on `OpenGLSurface` there are issues as `Surface` is a `VMObject` (vectorized) and `OpenGLSurface` is an `OpenGLMObject` (not vectorized). This can cause errors or unexpected behavior when running the same code in OpenGL (see code and log below).

## Expected behavior

`Dot3D` and other mobjects based on `Surface` and `OpenGLSurface` should behave the same in both Cairo and OpenGL.

## How to reproduce the issue

Code for reproducing the problem

```py
from manim import *
from manim.opengl import *

class Test(ThreeDScene):
def construct(self):
vect = Vector().to_edge(LEFT)
self.add(vect)
self.wait()
dot = Dot3D().to_edge(RIGHT)
self.add(dot)
self.wait()
self.play(Transform(vect, dot))
self.wait()
```

## Additional media files

Example of what Cairo outputs:

Images/GIFs

https://user-images.githubusercontent.com/79891353/137239258-e2a4203c-4494-4ca9-b689-95c55d16a598.mp4

## Logs
Terminal output

```
Manim Community v0.11.0

╭─────────────────────────────── Traceback (most recent call last) ────────────────────────────────╮
│ │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/cli/render/commands.py:108 in render │
│ │
│ 105 │ │ │ while keep_running: │
│ 106 │ │ │ │ for SceneClass in scene_classes_from_file(file): │
│ 107 │ │ │ │ │ scene = SceneClass(renderer) │
│ ❱ 108 │ │ │ │ │ rerun = scene.render() │
│ 109 │ │ │ │ │ if rerun or config["write_all"]: │
│ 110 │ │ │ │ │ │ renderer.num_plays = 0 │
│ 111 │ │ │ │ │ │ continue │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/scene/scene.py:213 in render │
│ │
│ 210 │ │ """ │
│ 211 │ │ self.setup() │
│ 212 │ │ try: │
│ ❱ 213 │ │ │ self.construct() │
│ 214 │ │ except EndSceneEarlyException: │
│ 215 │ │ │ pass │
│ 216 │ │ except RerunSceneException as e: │
│ │
│ /home/alexlembcke/ManimDev/vector_translation.py:13 in construct │
│ │
│ 10 │ │ dot = Dot3D().to_edge(RIGHT) │
│ 11 │ │ self.add(dot) │
│ 12 │ │ self.wait() │
│ ❱ 13 │ │ self.play(Transform(vect, dot)) │
│ 14 │ │ self.wait() │
│ 15 │
│ │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/scene/scene.py:888 in play │
│ │
│ 885 │ │ │ return np.max([animation.run_time for animation in animations]) │
│ 886 │ │
│ 887 │ def play(self, *args, **kwargs): │
│ ❱ 888 │ │ self.renderer.play(self, *args, **kwargs) │
│ 889 │ │
│ 890 │ def wait(self, duration=DEFAULT_WAIT_TIME, stop_condition=None): │
│ 891 │ │ self.play(Wait(run_time=duration, stop_condition=stop_condition)) │
│ │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/utils/caching.py:61 in wrapper │
│ │
│ 58 │ │ │ "List of the first few animation hashes of the scene: %(h)s", │
│ 59 │ │ │ {"h": str(self.animations_hashes[:5])}, │
│ 60 │ │ ) │
│ ❱ 61 │ │ func(self, scene, *args, **kwargs) │
│ 62 │ │
│ 63 │ return wrapper │
│ 64 │
│ │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/renderer/cairo_renderer.py:46 in │
│ wrapper │
│ │
│ 43 │ def wrapper(self, scene, *args, **kwargs): │
│ 44 │ │ self.animation_start_time = time.time() │
│ 45 │ │ self.file_writer.begin_animation(not self.skip_animations) │
│ ❱ 46 │ │ func(self, scene, *args, **kwargs) │
│ 47 │ │ self.file_writer.end_animation(not self.skip_animations) │
│ 48 │ │ self.num_plays += 1 │
│ 49 │
│ │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/renderer/opengl_renderer.py:406 in │
│ play │
│ │
│ 403 │ def play(self, scene, *args, **kwargs): │
│ 404 │ │ # TODO: Handle data locking / unlocking. │
│ 405 │ │ if scene.compile_animation_data(*args, **kwargs): │
│ ❱ 406 │ │ │ scene.begin_animations() │
│ 407 │ │ │ scene.play_internal() │
│ 408 │ │
│ 409 │ def clear_screen(self): │
│ │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/scene/scene.py:961 in │
│ begin_animations │
│ │
│ 958 │ def begin_animations(self) -> None: │
│ 959 │ │ """Start the animations of the scene.""" │
│ 960 │ │ for animation in self.animations: │
│ ❱ 961 │ │ │ animation.begin() │
│ 962 │ │
│ 963 │ def is_current_animation_frozen_frame(self) -> bool: │
│ 964 │ │ """Returns whether the current animation produces a static frame (generally a Wa │
│ │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/animation/transform.py:111 in begin │
│ │
│ 108 │ │ # Note, this potentially changes the structure │
│ 109 │ │ # of both mobject and target_mobject │
│ 110 │ │ if config["renderer"] == "opengl": │
│ ❱ 111 │ │ │ self.mobject.align_data_and_family(self.target_copy) │
│ 112 │ │ else: │
│ 113 │ │ │ self.mobject.align_data(self.target_copy) │
│ 114 │ │ super().begin() │
│ │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/mobject/opengl_mobject.py:1611 in │
│ align_data_and_family │
│ │
│ 1608 │ │
│ 1609 │ def align_data_and_family(self, mobject): │
│ 1610 │ │ self.align_family(mobject) │
│ ❱ 1611 │ │ self.align_data(mobject) │
│ 1612 │ │
│ 1613 │ def align_data(self, mobject): │
│ 1614 │ │ # In case any data arrays get resized when aligned to shader data │
│ │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/mobject/opengl_mobject.py:1619 in │
│ align_data │
│ │
│ 1616 │ │ for mob1, mob2 in zip(self.get_family(), mobject.get_family()): │
│ 1617 │ │ │ # Separate out how points are treated so that subclasses │
│ 1618 │ │ │ # can handle that case differently if they choose │
│ ❱ 1619 │ │ │ mob1.align_points(mob2) │
│ 1620 │ │ │ for key in mob1.data.keys() & mob2.data.keys(): │
│ 1621 │ │ │ │ if key == "points": │
│ 1622 │ │ │ │ │ continue │
│ │
│ /home/alexlembcke/.local/lib/python3.9/site-packages/manim/mobject/types/opengl_vectorized_mobje │
│ ct.py:856 in align_points │
│ │
│ 853 │ │ │ │ mob.start_new_path(mob.get_center()) │
│ 854 │ │ │ # If there's only one point, turn it into │
│ 855 │ │ │ # a null curve │
│ ❱ 856 │ │ │ if mob.has_new_path_started(): │
│ 857 │ │ │ │ mob.add_line_to(mob.points[0]) │
│ 858 │ │ │
│ 859 │ │ # Figure out what the subpaths are, and align │
╰──────────────────────────────────────────────────────────────────────────────────────────────────╯
AttributeError: 'Dot3D' object has no attribute 'has_new_path_started'
```

## System specifications

System Details

- OS: Ubuntu 21.04
- RAM: 32GB
- Python version (`python/py/python3 --version`): 3.9.5
- Installed modules (provide output from `pip list`):
```
Package Version
----------------------- ---------------------
manim 0.10.0
moderngl 5.6.4
moderngl-window 2.4.0
```

LaTeX details

+ LaTeX distribution (e.g. TeX Live 2020):
+ Installed LaTeX packages:

FFMPEG

Output of `ffmpeg -version`:

```
ffmpeg version 4.3.2-0+deb11u1ubuntu1 Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 10 (Ubuntu 10.2.1-20ubuntu1)
configuration: --prefix=/usr --extra-version=0+deb11u1ubuntu1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-pocketsphinx --enable-libmfx --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
libavutil 56. 51.100 / 56. 51.100
libavcodec 58. 91.100 / 58. 91.100
libavformat 58. 45.100 / 58. 45.100
libavdevice 58. 10.100 / 58. 10.100
libavfilter 7. 85.100 / 7. 85.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
libpostproc 55. 7.100 / 55. 7.100
```

## Additional comments

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the Vector-to-Dot3D Transform example, comparing Cairo and OpenGL. Start with animation/transform.py and mobject/opengl_mobject.py at align_data_and_family, then trace the scene/scene.py animation path. Done means Dot3D and other Surface/OpenGLSurface-based mobjects behave consistently in both renderers without the reported error.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
computer-graphics
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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