Animation State without render() function

fallen

All of the examples in the runtime documentation around using AnimationState and AnimationStateData require changes to the render function in the engine. For games that use a lot of Spines (such as a tactics RPG) having a loop inside the render function that locates the Spines, and calls to the following code. This looks like a huge amount of overhead for a game that has some 40+ Spines on the screen, some of which would be busy crossfading at any given time.

state.update(delta);
state.apply(skeleton);
skeleton.updateWorldTransform();
renderSkeleton(skeleton);

Is there a way to use AnimationState and AnimationStateData without having to use code to update / apply these changes every single render? A way to tell the Spine that it should cross fade from animation1 to animation2 over 1.0f second would be killer.

I have tried using SkeletonAnimation::setAnimationStateData(stateData) in the Cocos 2DX runtime, but basically see that the Skeleton ignores the API call, and does not run any animations from it. Is there a way to use setAnimationStateData successfully to avoid the explicit code in render()?

// get skeleton from our cache
spine::SkeletonAnimation* skel = getSkeletonAnimation("char_tactpoint");
// setup an animation state with a to and from animation, duration 1 second
AnimationStateData* stateData = spAnimationStateData_create(skel->skeleton->data);
Animation* attackAnimation = spSkeletonData_findAnimation(skel->skeleton->data, animation.c_str());
Animation* walkAnimation = spSkeletonData_findAnimation(skel->skeleton->data, "Walk");
spAnimationStateData_setMix(stateData, attackAnimation, walkAnimation, 1.0f);
// results in no visible animation
skel->setAnimationStateData(stateData);

Nate

Those functions are called every frame for good reason:

state.update increments the time for the animation. If you don't do this, the animation pose will never change. It is a tiny amount of work.

state.apply adjusts the skeleton's local pose for the animation at a specific time. If you don't do this, the skeleton won't animate because the pose doesn't change. The amount of work depends on the animation, the more timelines you have, the more work there is. Still, it's a small amount of work.

skeleton.updateWorldTransform calculates the world transforms for the skeleton. If you don't do this after changing the local pose, rendering won't see the changes. The amount of work depends on the number of bones you have. It is a small amount of work.

renderSkeleton draws the skeleton. If you don't do this, nothing is drawn.

Which of these can you remove? Probably none. Why are you worried about the amount of work that is done? If you saw all the junk that cocos2d-x is doing under the covers, you'd see this amount of work is small, even with quite a few characters. Unless you have a performance problem, I would say there is nothing to be done here.

AnimationStateData stores mix values for use when an animation changes from one to another. This doesn't help you avoid the above.

fallen

@Nate - thanks for the reply. I was asking because I am a huge fan of the following API call

spine->setAnimation(0, "name", true);

This allows the internal rendering engine of the runtime and the spine to take care of the work. One line, easy animation. I was asking, is there an easy way to push a setup animation state onto a skeleton and then not have to worry about managing it in the render loop.

It seems like the answer is a no, but thanks for the reply!

Nate

You can do this:

spine->setAnimation(0, "name1", true); 
spine->addAnimation(0, "name2", false, 0); 
spine->addAnimation(0, "name3", true, 0);

Using Spine Runtimes

fallen

Nate schrieb

You can do this:

spine->setAnimation(0, "name1", true); 
spine->addAnimation(0, "name2", false, 0); 
spine->addAnimation(0, "name3", true, 0);

Using Spine Runtimes

Well, ... awesome! Thank you for pointing that out @Nate. :yes:

I don't see a description of that function in the Using Spine Runtime documentation, but I am excited to use it. The only reference is in adding animations to AnimationState. Sorry I missed it.

Nate

No worries. 🙂 It's just a convenience method on the cocos2d-x object for calling addAnimation on the AnimationState, so you don't have to bother with the spine-c API for such common usage:
spine-runtimes/SkeletonAnimation.cpp at master · EsotericSoftware/spine-runtimes · GitHub

fallen

@Nate - thanks again for pointing this out. The ability to put in the delay argument is really valuable.

It does not seem to effect a cross-fade between the added animations. Was that expected, or to achieve a cross-fade the AnimationStateData objects and code is required? Thanks for the help.

I am doing the following:

// previously ... set the spine to walking
skel->setAnimation(0, "Walk", true);
// on key press
skel->addAnimation(0, "Fire Gun", false, 0.0f);
skel->addAnimation(0, "Walk", true, 1.0f);

Nate

The mix time (crossfade time) is defined by AnimationStateData.

fallen

Nate schrieb
The mix time (crossfade time) is defined by AnimationStateData.

@Nate - Got it working. Sorry about the start of this thread. I was confused that the examples in the documentation were asking users to write the code in the render() function. After consulting other examples, like Applying Animations I finally realized that isn't what the doc was indicating, instead it was including the render() as an educational point (i.e. this is what the runtime does). I got hung up, as I didn't want to have to write the render code 😉 Clearly, you've done that already!

Here is the example code that would have helped me without having to post on the boards:

// create a new spine skeleton
Skeleton skeleton = new Skeleton(skeletonData);
// animation state data will maintain information about cross fades
AnimationStateData stateData = new AnimationStateData(skeletonData);
// when we transition from walk to jump, crossfade in 0.2f seconds
stateData.setMix("walk", "jump", 0.2f);
// when we transition from jump to walk, crossfade in 0.4f seconds
stateData.setMix("jump", "walk", 0.4f);
// instruct the new spine skeleton to use this animation data
skeleton->setAnimationStateData(stateData);
// now, whenever an animation is set or added, smooth crossfades are applied
skeleton->setAnimation(0, "walk", true);
// later
skeleton->addAnimation(0, "jump", false);

Crossfade is now working great for me. I have one occasion where we control the rotation of a bone before an animation with code, but when I add an AnimationStateData object into the picture, the code-driven rotation stops happening. If I stop calling skel->setAnimationStateData(stateData) it starts working again.

I am okay if this is the case

we won't use cross-fade on that spine and it will just be a little jumpy. But I was curious if there is a solution I am missing.

spine::SkeletonAnimation* skel = getSkeleton(...);
// get the bone we need to rotate
spBone* defenseGun = skel->findBone("Defense Gun");
// calculate the rotation angle
float rotationCalc = ... // math here
// rotation the bone manually 
defenseGun->rotation = rotationCalc;
// update the SRT after the rotation
skel->updateWorldTransform();
// also tried this, but didn't work
spBone_updateWorldTransform(defenseGun);