Enable CI testing for OpenGL (3b1b#1160)

* add simple circle test for opengl

* literally a comma

* add rgb tolerance to graphical unit tester

* start up xvfb on ubuntu?

* black style

* reduce tolerance to pixel ?

* add msys2 action

* add mesa install

* ci: windows add msys2 to path
Compile moderngl from source
add a init tests for CI to work
add colour to pytest

* minor edits

* mild refactor of scene / camera / renderer relationship

* flake-d

* reverted refactor

* reverted opengl split at the level of graphical unit tester

* remove unnecessary config in definition

* CI: remove python3 from MSYS2 also

Co-authored-by: Naveen M K <[email protected]>

.github/workflows/ci.yml

@@ -12,6 +12,8 @@ jobs:
     runs-on: ${{ matrix.os }}
     env:
       POETRY_VIRTUALENVS_CREATE: false
+      DISPLAY: :0
+      PYTEST_ADDOPTS: "--color=yes" # colors in pytest
     strategy:
       fail-fast: false
       matrix:
@@ -37,8 +39,10 @@ jobs:
         run: |
           sudo apt update
           sudo apt install -y ffmpeg
-          sudo apt-get -y install texlive texlive-latex-extra texlive-fonts-extra texlive-latex-recommended texlive-science texlive-fonts-extra tipa python-opengl libpango1.0-dev
+          sudo apt-get -y install texlive texlive-latex-extra texlive-fonts-extra texlive-latex-recommended texlive-science texlive-fonts-extra tipa python-opengl libpango1.0-dev xvfb
           echo "$HOME/.poetry/bin" >> $GITHUB_PATH
+          # start xvfb in the background
+          sudo /usr/bin/Xvfb $DISPLAY -screen 0 1280x1024x24 &
 
       - name: Install system dependencies (MacOS)
         if: runner.os == 'macOS'
@@ -77,6 +81,16 @@ jobs:
           path: ${{ github.workspace }}\ManimCache
           key: ${{ runner.os }}-dependencies-ffmpeg-tinytex-${{ hashFiles('.github/manimdependency.json') }}-${{ steps.pip-cache-and-time.outputs.date }}
 
+      - name: Setup MSYS2
+        if: runner.os == 'Windows'
+        uses: msys2/setup-msys2@v2
+        with:
+          release: false
+          msystem: MINGW64
+          path-type: inherit
+          install: >-
+            mingw-w64-x86_64-mesa
+
       - name: Download system dependencies (Windows)
         if: runner.os == 'Windows' && steps.cache-windows.outputs.cache-hit != 'true'
         run: |
@@ -105,10 +119,13 @@ jobs:
       - name: Add Windows dependecies to path
         if: runner.os == 'Windows'
         run: |
+          Remove-Item C:\msys64\mingw64\bin\python.exe -Force
+          Remove-Item C:\msys64\mingw64\bin\python3.exe -Force
           $env:Path += ";" + "$($PWD)\ManimCache\FFmpeg\bin"
           $env:Path += ";" + "$($PWD)\ManimCache\LatexWindows\TinyTeX\bin\win32"
           $env:Path += ";" + "$($PWD)\ManimCache\Pango\pango"
           $env:Path = "$env:USERPROFILE\.poetry\bin;$($env:PATH)"
+          $env:PATH = "C:\msys64\mingw64\bin;$($env:PATH)"
           echo "$env:Path" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
 
       - name: Install manim

manim/renderer/opengl_renderer.py

@@ -440,6 +440,13 @@ def get_raw_frame_buffer_object_data(self, dtype="f1"):
         )
         return ret
 
+    def get_frame(self):
+        # get current pixel values as numpy data in order to test output
+        raw = self.get_raw_frame_buffer_object_data(dtype="f1")
+        result_dimensions = (config["pixel_height"], config["pixel_width"], 4)
+        np_buf = np.frombuffer(raw, dtype="uint8").reshape(result_dimensions)
+        return np_buf
+
     # Returns offset from the bottom left corner in pixels.
     def pixel_coords_to_space_coords(self, px, py, relative=False):
         pw, ph = config["pixel_width"], config["pixel_height"]

tests/__init__.py

@@ -0,0 +1,10 @@
+import os
+
+if os.getenv("CI") and os.name == "nt":
+    location = r"C:\msys64\mingw64\bin"
+    os.environ["PATH"] = location + os.pathsep + os.getenv("PATH")
+    import ctypes
+
+    ctypes.CDLL(r"C:\msys64\mingw64\bin\OPENGL32.dll")
+    if hasattr(os, "add_dll_directory"):
+        os.add_dll_directory(location)

tests/test_graphical_units/test_opengl.py

@@ -0,0 +1,25 @@
+import pytest
+
+from manim import *
+from manim.opengl import *
+from ..utils.testing_utils import get_scenes_to_test
+from ..utils.GraphicalUnitTester import GraphicalUnitTester
+
+
+class CircleTest(Scene):
+    def construct(self):
+        circle = OpenGLCircle().set_color(RED)
+        self.add(circle)
+        self.wait()
+
+
+MODULE_NAME = "opengl"
+
+
+@pytest.mark.parametrize("scene_to_test", get_scenes_to_test(__name__), indirect=False)
+def test_scene(scene_to_test, tmpdir, show_diff):
+    with tempconfig({"use_opengl_renderer": True}):
+        # allow 1/255 RGB value differences with opengl tests because of differences across platforms
+        GraphicalUnitTester(scene_to_test[1], MODULE_NAME, tmpdir, rgb_atol=1.01).test(
+            show_diff=show_diff
+        )

tests/utils/GraphicalUnitTester.py

@@ -3,14 +3,15 @@
 import numpy as np
 
 from manim import config, tempconfig
+from manim.renderer.opengl_renderer import OpenGLRenderer
 
 
 class GraphicalUnitTester:
     """Class used to test the animations.
 
     Parameters
     ----------
-    scene_object : :class:`~.Scene`
+    scene_class : :class:`~.Scene`
         The scene to be tested
     config_scene : :class:`dict`
         The configuration of the scene
@@ -27,12 +28,7 @@ class GraphicalUnitTester:
         The scene tested
     """
 
-    def __init__(
-        self,
-        scene_object,
-        module_tested,
-        tmpdir,
-    ):
+    def __init__(self, scene_class, module_tested, tmpdir, rgb_atol=0):
         # Disable the the logs, (--quiet is broken) TODO
         logging.disable(logging.CRITICAL)
         tests_directory = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
@@ -41,11 +37,12 @@ def __init__(
             "test_graphical_units",
             "tests_cache",
             module_tested,
-            scene_object.__name__,
+            scene_class.__name__,
         )
         self.path_control_data = os.path.join(
             tests_directory, "control_data", "graphical_units_data", module_tested
         )
+        self.rgb_atol = rgb_atol
 
         # IMPORTANT NOTE : The graphical units tests don't use for now any
         # custom manim.cfg, since it is impossible to manually select a
@@ -64,7 +61,10 @@ def __init__(
             os.makedirs(dir_temp)
 
         with tempconfig({"dry_run": True}):
-            self.scene = scene_object(skip_animations=True)
+            if config["use_opengl_renderer"]:
+                self.scene = scene_class(renderer=OpenGLRenderer())
+            else:
+                self.scene = scene_class(skip_animations=True)
             self.scene.render()
 
     def _load_data(self):
@@ -126,15 +126,17 @@ def test(self, show_diff=False):
             + f"\nframe_data.shape = {frame_data.shape}"
         )
 
-        test_result = np.array_equal(frame_data, expected_frame_data)
-        if not test_result:
-            incorrect_indices = np.argwhere(frame_data != expected_frame_data)
+        mismatches = np.logical_not(
+            np.isclose(frame_data, expected_frame_data, atol=self.rgb_atol, rtol=0)
+        )
+        if mismatches.any():
+            incorrect_indices = np.argwhere(mismatches)
             first_incorrect_index = incorrect_indices[0][:2]
             first_incorrect_point = frame_data[tuple(first_incorrect_index)]
             expected_point = expected_frame_data[tuple(first_incorrect_index)]
             if show_diff:
                 self._show_diff_helper(frame_data, expected_frame_data)
-            assert test_result, (
+            assert not mismatches.any(), (
                 f"The frames don't match. {str(self.scene).replace('Test', '')} has been modified."
                 + "\nPlease ignore if it was intended."
                 + f"\nFirst unmatched index is at {first_incorrect_index}: {first_incorrect_point} != {expected_point}"