"Current value to X" key interpolation

Xelnath

Hey so, a question, what's the intended way to make a key interpolate from whatever its current value is to another value at time X?

Basically, in this case, I have a tinted slot, whose color I don't care about, that I want to turn to 0,0,0,0 (transparent black), however, I do want to control the graph and duration for how it changes.

However, since another animation is cycling the color of the slot, red, yellow, green, etc, I don't want the color to 'snap' to green if it was red - I just want the thing to fade out.

What's the right way to implement this?
Similar question for positional keys - if I have a ghostly stop light, I want it to float back to 0,0 - In this case, I think I can just use a Transform constraint and control the mix.

-Alex

Xelnath

Pharan

Honestly confused.

You want a slot color to transition from any color to transparent black? Just key any color at one point, then key the transparent black at a later point.
Why would it snap to green?

Xelnath

Imagine:

Animation One:

Looping... Red to Blue to Yellow to Red.

Animation Two:

Non-looping... 'Off' - I want it to slowly blend from whatever color it was in Animation 1 when it gets interrupted to Transparent Black at the end of Animation two. .

If I set 2 keys in Animation Two, then it will blend from color 2A to color 2B with a 0.2 sec mix.

Do I make sense yet?

nimbling

Perhaps add a bunch of in-between keys to facilitate the blend?

Also: does this have to do with keys being read or not during animation blends?

In this case, would the "curve timeline behavior" (as described here: Only getting Animation Additive. How to get Override? ) help you?

Xelnath

I am really, really confused as to how I'm not getting this point across.

I'll be super explicit:

[Animation1: Loop]

Frame 0:
Slot Color - 255, 0, 0, 1

Frame 24:

Slot Color - 0, 255, 0, 1

[Animation 2: TurnOff]

Frame 120:

Slot Color - 0, 0, 0, 0

Assume the spine file is playing the animation "Loop" on Track 0.

Variation 1:
At time 12 (Frame 12), I interrupt the loop animation and tell it to SetAnimation("TurnOff", loop: false, delay: 0f);

What will happen is:
The color of the slot will freeze at whatever frame 12 was (probably 127, 127, 0, 1).

Actual behaviour:
No change in the color, then at frame 120 of "TurnOff", it will snap to invisible black.

Desired behaviour:
It will blend from 127, 127, 0, 1 to 0,0,0,0 over 120 frame.

Alternate example, a bit more clear:

Track 0 - [Loop]:
Cycles from Red, to Green, to Blue to Red again

Track 1 - [PowerDown]:
Slowly runs the light down.

Sets a track that says: "Whatever color exists on the slot, keep it, but change the alpha from 1.0 to 0.0"

It would not interrupt the lower track and would allow the colors to keep cycling while slowly dimming the light.

nimbling

In your second animation, did you set a frame 0?
(In case of no, you need to.)

Xelnath

If you set a Frame 0, then that value of the color will be blended into... which is my whole point.

e.g.

If I do it your way:

Track1: Loop as Red to Green.

Set Frame 0 of Track 2 as Blue 100% alpha, Frame 120 as Black 0% alpha.

Interrupt Track 1 looping at 50% (yellowish), it will then blend to blue over a 0.2 sec mix time, then go from blue to black over the other 110 frames.

What I want is for the slot to go from its CURRENT color to transparent, no matter what hue....

nimbling

Then I think you're best off coding this, I don't see how you could instruct spine to do this for you.

Xelnath

I can see two methods:

Option 1:

A 'Snapshot initial value' key type. It essentially saves the value when the animation starts and then creates the animation curve based on that value.

Option 2:

A Transform-constraint-like structure that allow you to override a slot color by % of value.

In this scenario, instead of keying the value directly, you key the blend amount.

Nate

This seems to be a runtime question, not something for the editor. You can to set a mix time using AnimationStateData, eg so it takes 1 second to mix from animation A to B. Animation A can apply whatever colors, B would apply 0,0,0,0 (for your "power off" scenario). During the mix time it will transition (crossfade) from A's color to B's color. It's not possible to key only alpha, but setting RGB to 0 is probably good enough.

If you don't set B to looping, it'll be applied until its last frame (it's duration) is reached. If it's only got 1 frame, this won't be what you want. In that case, you can set endTime on the TrackEntry (returned from SetAnimation) so it keeps applying the animation beyond it's duration. You could also set a key in B so the duration is at least as long as the mix time. Or you could just set it to looping, which means it'll be applied forever (even after the mix time).

Xelnath

Hmmm, in that case, would it just be simpler to have a 2nd track running with the 'off' state (a looping animation that is 0,0,0,0 to 0,0,0,0) and directly adjusting the weight of the track?

Of course, the downside here is that the mix is linear and any animation curves would need to be created in the engine. Still doable.