Properly define init_points methods for use in OpenGL instead of defining init_points = generate_points

[chopan050]

As mentioned in a comment thread to PR #4003, there are multiple definitions of init_points which look like

init_points = generate_points

This caused the bug which was fixed in #4003. The solution there was to properly define init_points as

def init_points(self) -> None:
    self.generate_points()

This PR fixes the rest of such definitions so that init_points is properly defined as stated above in every class which defines it.

Reviewer Checklist

• The PR title is descriptive enough for the changelog, and the PR is labeled correctly
• If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
• If applicable: newly added functions and classes are tested

[behackl]

Thanks!