spine-runtimes/spine-cocos2dx/example/Classes/IKExample.cpp

/******************************************************************************
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 * Last updated April 5, 2025. Replaces all prior versions.
 *
 * Copyright (c) 2013-2025, Esoteric Software LLC
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#include "IKExample.h"
#include "PhysicsExample.h"

USING_NS_CC;
using namespace spine;

// This example demonstrates how to set the position
// of a bone based on the touch position, which in
// turn will make an IK chain follow that bone
// smoothly.
Scene *IKExample::scene() {
	Scene *scene = Scene::create();
	scene->addChild(IKExample::create());
	return scene;
}

bool IKExample::init() {
	if (!LayerColor::initWithColor(Color4B(128, 128, 128, 255))) return false;

	// Load the Spineboy skeleton and create a SkeletonAnimation node from it
	// centered on the screen.
	skeletonNode = SkeletonAnimation::createWithJsonFile("spineboy-pro.json", "spineboy.atlas", 0.6f);
	skeletonNode->setPosition(Vec2(_contentSize.width / 2, 20));
	addChild(skeletonNode);

	// Queue the "walk" animation on the first track.
	skeletonNode->setAnimation(0, "walk", true);

	// Queue the "aim" animation on a higher track.
	// It consists of a single frame that positions
	// the back arm and gun such that they point at
	// the "crosshair" bone. By setting this
	// animation on a higher track, it overrides
	// any changes to the back arm and gun made
	// by the walk animation, allowing us to
	// mix the two. The mouse position following
	// is performed in the lambda below.
	skeletonNode->setAnimation(1, "aim", true);

	// Next we setup a listener that receives and stores
	// the current mouse location. The location is converted
	// to the skeleton's coordinate system.
	EventListenerMouse *mouseListener = EventListenerMouse::create();
	mouseListener->onMouseMove = [this](cocos2d::Event *event) -> void {
		// convert the mosue location to the skeleton's coordinate space
		// and store it.
		EventMouse *mouseEvent = dynamic_cast<EventMouse *>(event);
		position = skeletonNode->convertToNodeSpace(mouseEvent->getLocationInView());
	};
	_eventDispatcher->addEventListenerWithSceneGraphPriority(mouseListener, this);

	// Position the "crosshair" bone at the mouse
	// location.
	//
	// When setting the crosshair bone position
	// to the mouse position, we need to translate
	// from "skeleton space" to "local bone space".
	// Note that the local bone space is calculated
	// using the bone's parent worldToLocal() function!
	//
	// After updating the bone position based on the
	// converted mouse location, we call updateWorldTransforms()
	// again so the change of the IK target position is
	// applied to the rest of the skeleton.
	skeletonNode->setPostUpdateWorldTransformsListener([this](SkeletonAnimation *node) -> void {
		Bone *crosshair = node->findBone("crosshair");// The bone should be cached
		float localX = 0, localY = 0;
		crosshair->getParent()->worldToLocal(position.x, position.y, localX, localY);
		crosshair->setX(localX);
		crosshair->setY(localY);

		node->getSkeleton()->updateWorldTransform(spine::Physics_Update);
	});

	EventListenerTouchOneByOne *listener = EventListenerTouchOneByOne::create();
	listener->onTouchBegan = [this](Touch *touch, cocos2d::Event *event) -> bool {
		Director::getInstance()->replaceScene(PhysicsExample::scene());
		return true;
	};

	_eventDispatcher->addEventListenerWithSceneGraphPriority(listener, this);

	scheduleUpdate();

	return true;
}

void IKExample::update(float deltaTime) {
}