Highlight points on hover in the Polygon2D editor

[Nikitf777]

The Polygon2D editor now highlights a point, if it's near the mouse cursor. It especially useful on touchpads, where it's much harder to aim.
But I was surprised how much it improves the mouse experience as well. And now I don't want to go back to the previuos behavior, because it was awful.
However, the Polygon2D editor is far from perfect and still needs a few improvements.

polygon2d-editor-highlighting.mp4

The downside of this improvement is performance, because now the editor needs to redraw more often and iterate through the array of points on every mouse move. However, it's well optimized, because it redraws only when the highlighted point is changed and avoids looping when is_creating is true, checking only the first point.

[AdriaandeJongh]

Does this also apply to the polygon editor in the scene view? If not, it should!

[Nikitf777]

If I understand correctly what you mean, it seems like it was already implemented.

polygon2d-editor-highlighting-2.mp4

[AdriaandeJongh]

Ah, yup! Maybe use the same colors then?

[Nikitf777]

But they already look differenlty in a few ways. So I don't think that the color must be the same.

Also, when you add an internal vertex, you lose the ability to view and edit it in the scene view. So making the highlighted color of internal vertices the same, as in scene view, is impossible (because there're no internal vertices in the scene view).

A much closer reference is the AnimationPlayer editor. But it applies the same (or almost the same) color, that the Polygon2D editor uses for unhighlighted internal vertices:

animation-player-highlight.mp4

[smix8]

The main performance problem of Polygon2D editor is because it still uses the inefficient canvas draw functions for every single line and handle texture, aka every single vertex edge segment is its own canvas item and draw in the editor. It basically creates a new throwaway mesh for every single handle point that it deletes on the next redraw, oc performance is bad with that on larger polygons.

Should be switched to use static meshes and multimeshes like done for Path2D editor in PR #105606

[Nikitf777]

Should be switched to use static meshes and multimeshes like done for Path2D editor in PR #105606

Do you think I should apply the same fix in this PR? It's a little bit out of its scope.

[smix8]

Do you think I should apply the same fix in this PR? It's a little bit out of its scope.

Nono that is very much out of scope and should be its own PR. That was in response to the comment about performance.

[KoBeWi]

Suggested change

	int highlighted_point = -1;
	int hovered_point = -1;

More accurate.

[KoBeWi]

Suggested change

	// Highlight a point near the cursor
	// Highlight a point near the cursor.

[KoBeWi]

There is actually a minor bug. When you undo deleting a point, it's not immediately hovered:

qa75H4PB1Q.mp4

[Nikitf777]

Well, I wouldn't even call it a bug. It's a normal behavior for this kind of thing.
Here is the same thing:

the-same-behavior.mp4

[Nikitf777]

Also there is a similar "bug" in the GNOME desktop:

Screencast.From.2025-06-30.15-11-25.mp4

[Nikitf777]

I think I should make another push

[Nikitf777]

I think it's better to check for selected_action == ACTION_... here

[Nikitf777]

Also I can split this code into three separate loops to avoid checking for wight_r and i >= uv_draw_max on every iteration and to simplify logic:

	if (weight_r) {
		for (int i = 0; i < uvs.size(); i++) {
			Vector2 draw_pos = mtx.xform(uvs[i]);
			float weight = weight_r[i];
			canvas->draw_rect(Rect2(draw_pos - Vector2(2, 2) * EDSCALE, Vector2(5, 5) * EDSCALE), Color(weight, weight, weight, 1.0), Math::round(EDSCALE));
		}
	} else {
		Vector2 texture_size_half = handle->get_size() * 0.5;
		for (int i = 0; i < uv_draw_max; i++) {
			Color mod(1, 1, 1);
			if (i == hovered_point && selected_action != ACTION_REMOVE_INTERNAL) {
				mod = Color(0.63, 0.63, 0.63);
			}
			canvas->draw_texture(handle, mtx.xform(uvs[i]) - texture_size_half, mod);
		}
		// Internal vertices.
		for (int i = uv_draw_max; i < uvs.size(); i++) {
			Color mod(0.6, 0.8, 1);
			if (i == hovered_point) {
				mod = Color(0.35, 0.55, 0.75);
			}
			canvas->draw_texture(handle, mtx.xform(uvs[i]) - texture_size_half, mod);
		}
	}

[Nikitf777]

Now this code even more optimized that before the PR

[Repiteo]

Needs rebase

[Repiteo]

Thanks!