added Curve in state machine interpolation

[jeronimo-schreyer]

added Curve in state machine interpolation for better control over blending
theres a proposal for this godotengine/godot-proposals#1402

here you can see the interpolation with and without curve setting

blend_tree_curve.mp4

[Calinou]

@jeronimo-schreyer Remember that for GitHub video previews to work, you need to have a blank line before and after the video URL. I edited your post accordingly, but remember to do this in the future 🙂

[jeronimo-schreyer]

I didn't know why I could see it OK in the preview and not in the final posted version. Thanks.

This build error says I need to add documentation for the new Curve property, right?

[Calinou]

This build error says I need to add documentation for the new Curve property, right?

Yes, and make sure you're using tab indentation within the XML instead of spaces (except within [codeblock]).

[jeronimo-schreyer]

I'm almost certain I use tabs instead of spaces. Is there a way to be sure?

[TokageItLab]

IMO it is good, it could be implemented also for NodeTransition, but maybe after this is Approved, we can send it as an additional PR.

[jeronimo-schreyer]

I added this for NodeTransition also on my latest commit. I even changed a property name cross_fade_time for xfade_time to keep consistency in names between them

[TokageItLab]

You must follow the rebasing work-flow recommended by Godot. See Pull request workflow.

In brief, check out 74d84d170aab4e692a81165872f040296a2ca7f0 and apply the fixes, then do a --fixup. In the end, there should be only one commit.

[TokageItLab]

Interpolation calculation is wrong; you only need to overwrite blend with curve.

Suggestion:

	} else { // cross-fading from prev to current

		float blend = xfade_time == 0 ? 0 : (prev_xfading / xfade_time);
		if (xfade_curve.is_valid()) {
			blend = xfade_curve->interpolate(blend);
		}

		if (from_start && !p_seek && switched) { //just switched, seek to start of current

			rem = blend_input(current, 0, true, p_seek_root, 1.0 - blend, FILTER_IGNORE, true);
		} else {
			rem = blend_input(current, p_time, p_seek, p_seek_root, 1.0 - blend, FILTER_IGNORE, true);
		}

		if (p_seek) {
			blend_input(prev, p_time, true, p_seek_root, blend, FILTER_IGNORE, true);
			time = p_time;
		} else {
			blend_input(prev, p_time, false, p_seek_root, blend, FILTER_IGNORE, true);
			time += p_time;
			prev_xfading -= p_time;
			if (prev_xfading < 0) {
				set_parameter(this->prev, -1);
			}
		}
	}

[TokageItLab]

Same above.

Suggestion:

	if (current_curve.is_valid()) {
		fade_blend = current_curve->interpolate(fade_blend);
	}
	float rem = p_state_machine->blend_node(current, p_state_machine->states[current].node, p_time, p_seek, p_seek_root, fade_blend, AnimationNode::FILTER_IGNORE, true);

	if (fading_from != StringName()) {
		p_state_machine->blend_node(fading_from, p_state_machine->states[fading_from].node, p_time, p_seek, p_seek_root, 1.0 - fade_blend, AnimationNode::FILTER_IGNORE, true);
	}

[TokageItLab]

@jeronimo-schreyer This feature is good. Can I salvage it?
We have to do a feature freeze to release the Godot 4 beta (https://godotengine.org/article/godot-4-0-development-enters-feature-freeze), so implementation of the new feature is a bit rushed. If I don't hear back by 8/2, I will send a proxy PR with your name as co-authored.

[akien-mga]

Superseded by #63802.