[SOLVED] Setting animation play rate

C++ coding using Panda3D
1

Hi!

I am using C++ for working with Panda3d and need to increase and decrease the playing rate of animation depending on input by the HMD device.
I noticed python wrapper for models with animations (Actor) is huge. I don’t have enough time on my hands to reverse it and come out with a C++ function. It would be great if someone helped me with this - i.e. how to set an animation’s play rate depending on a variable that constantly changes with time, in C++.

I have two egg files, one holding the model and other, animation.

2

Why can’t you use the provided way? Can’t you pass your variable to set_play_rate?

3

The provided way that you have mentioned is for Python and has been implemented in Actor class, which is a wrapper for controlling models with animation.

The set_play_rate function that you have mentioned is from AnimInterface specification. As I recall, interfaces have only declarations and no definitions. To use this method, I’d have to use a class that implements it, which I am unable to find :frowning:
AnimControl’s source file does not contain the implementation of this methd :frowning:

4

AnimControl inherits from AnimInterface, and thus also inherits set_play_rate().

David

5

I guess I mixed up my C# and C++ background. Sorry!

I refered some other post by you and wrote the follwoing lines

NodePath child = this->jester.find("**/+Character");
			
assert(!child.is_empty());
Character *ch = DCAST(Character, child.node());
assert(ch != NULL);
			
PartBundle *bundle = ch->get_bundle(0);
assert(bundle != NULL); 
animControl = new AnimControl(animationName, bundle, 30, 60);

AnimControl *animControl is member of a class that holds the path of the animation in form “…/…/models/anim.egg”.

When I do animControl->play() or animControl->set_play_rate(0.1), nothing’s happening. I think this is because I have not associated any model to animControl. Can this be the reason for nothing happening? If yes, then how do I associate the model to the animControl object? What else can be wrong?

Looks like the object is already associated via the PartBundle. So what can be the problem now?
6

You can’t create an AnimControl directly; its constructor is only public because other systems within Panda need to construct an AnimControl.

An AnimControl is normally created as the result of binding a Character to its animation. A correctly-constructed AnimControl returned by PartBundle::bind_anim().

You can call bind_anim() directly, but the easiest way to create an AnimControl in C++ code is to use the auto_bind() function; there is an illustration of this in the pview.cxx source code, and probably in several forum posts.

Edit: also note that, as a reference-counted object, you must store the AnimControl pointer in a PT(AnimControl) object, and not an AnimControl * object. This is necessary to retain the reference count and prevent the AnimControl from being inadvertently destructed before you can use it.

David

7

Thanks David!! That resolved the issue. I am posting the class for someone who may find it useful. The code is not in a presentable state, but it works.

class Jester
{
	public:
		Jester(WindowFramework *window, NodePath parent, string path)
		{
			jester = window->load_model(parent, path);
		}

	private:
		NodePath jester;
		char* animationName;
		AnimControlCollection animControls;
	public:
		NodePath getJesterNodepath()
		{
			return jester;
		}

		void setJester(NodePath model)
		{
			jester = model;
		}

		void reparentTo(NodePath parent)
		{
			jester.reparent_to(parent);
		}
		
		void loadAnimation(WindowFramework *window, char* animationName)
		{
			this->animationName = animationName;
			window->load_model(this->jester, animationName);

			//Auto bind the animations to controls
			auto_bind(this->jester.node(), this->animControls, PartGroup::HMF_ok_part_extra | PartGroup::HMF_ok_anim_extra | PartGroup::HMF_ok_wrong_root_name); 

		}

		char* getAnimationName()
		{
			return animationName;
		}

		void setPlayRate(float rate)
		{
			for (int i=0; i<animControls.get_num_anims(); i++)
				animControls.get_anim(i)->set_play_rate(rate);
		}

		void play()
		{
			for (int i=0; i<animControls.get_num_anims(); i++)
				animControls.get_anim(i)->play();
		}

		void setLoop(bool isLoop)
		{
			for (int i=0; i<animControls.get_num_anims(); i++)
				animControls.get_anim(i)->loop(isLoop);
		}

		AnimControlCollection getAnims()
		{
			return animControls;
		}
};

Calls-

Jester *j = new Jester(window, framework.get_models(), "../../models/jester_violin.egg" );
j->reparentTo(window->get_render());
j->getJesterNodepath().set_scale(0.1);
j->getJesterNodepath().set_pos(0,0,2);
j->loadAnimation(window, "../../models/jester_violin_anim.egg");
j->setLoop(true);
j->setPlayRate(0.1);
j->play();