[spine-unity] Sample code for how to dynamically create and image-swap a linked MeshAttachment.

LinkedMeshSample.cs

/*****************************************************************************
 * LinkedMeshSample code created by John Dy
 * Full irrevocable rights and permissions granted to Esoteric Software
*****************************************************************************/
using UnityEngine;
using System.Collections;
using Spine;
using Spine.Unity;

public class LinkedMeshSample : MonoBehaviour {
	SkeletonAnimation skeletonAnimation;
	[SpineSlot] public string slotName;

	[Header("Parent/Master Mesh")]
	[SpineSkin] public string skinOfParent;
	[SpineAttachment(slotField:"slotName")] public string parentAttachment;

	[Header("New Linked Mesh")]
	public string linkedMeshName = "New Linked Mesh";
	public AtlasAsset atlasAsset;
	[SpineAtlasRegion] public string regionName;
	[SpineAtlasRegion] public string anotherRegionForFun;

	IEnumerator Start () {
		skeletonAnimation = GetComponent<SkeletonAnimation>();

		// Find the parent mesh
		MeshAttachment parentMesh = LinkedMeshUtilities.FindAttachment(skeletonAnimation.skeleton, slotName, skinOfParent, parentAttachment) as MeshAttachment;
		if (parentMesh == null) {
			Debug.LogError(parentAttachment + " in [" + skinOfParent + "] is not a MeshAttachment.");
			yield break;	
		}

		// Make a new linked mesh and give it an image
		AtlasRegion region = atlasAsset.GetAtlas().FindRegion(regionName);
		MeshAttachment newLinkedMesh = LinkedMeshUtilities.NewLinkedMeshAttachment(linkedMeshName, region, parentMesh);
		skeletonAnimation.skeleton.FindSlot(slotName).Attachment = newLinkedMesh; // Swap the parent mesh in its slot with the newly created linked mesh.

		// For fun, change the image of the existing linked mesh after 2 seconds.
		yield return new WaitForSeconds(2f);
		AtlasRegion region2 = atlasAsset.GetAtlas().FindRegion(anotherRegionForFun);
		LinkedMeshUtilities.SetRegion(newLinkedMesh, region2);
	}

	public static class LinkedMeshUtilities {
		
		/// <summary>May return null if the attachment is not found.</summary>
		static public Attachment FindAttachment (Skeleton skeleton, string slotName, string skinName, string attachmentName) {
			int slotIndex = skeleton.FindSlotIndex(slotName);
			Skin skin = string.IsNullOrEmpty(skinName) ? skeleton.data.defaultSkin : skeleton.data.FindSkin(skinName);
			Attachment attachment = skin.GetAttachment(slotIndex, attachmentName);
			return attachment;
		}

		/// <summary>Instantiate a new MeshAttachment with a region, and linked to parentMesh.</summary>
		static public MeshAttachment NewLinkedMeshAttachment (string attachmentName, AtlasRegion region, MeshAttachment parentMesh, bool inheritDeform = true) {
			if (string.IsNullOrEmpty(attachmentName)) throw new System.ArgumentException("attachmentName can't be null or empty.", "attachmentName");
			if (region == null) throw new System.ArgumentNullException("region");
			if (parentMesh == null) throw new System.ArgumentNullException("parentMesh");

			// 1. NewMeshAttachment (AtlasAttachmentLoader.cs)
			MeshAttachment mesh = new MeshAttachment(attachmentName);
			SetRegion(mesh, region, false);

			// 2. ReadAttachment. case: LinkedMesh (SkeletonJson.cs)
			mesh.Path = attachmentName;
			mesh.r = 1f;
			mesh.g = 1f;
			mesh.b = 1f;
			mesh.a = 1f;
			// Setting width and height is redundant when setting ParentMesh.
			//mesh.Width = masterMesh.Width;
			//mesh.Height = masterMesh.Height;

			// 3. Link mesh with parent. (SkeletonJson.cs)
			mesh.InheritFFD = inheritDeform;
			mesh.ParentMesh = parentMesh;
			mesh.UpdateUVs();

			return mesh;
		}

		/// <summary>Sets the region (image) of a MeshAttachment</summary>
		static public void SetRegion (MeshAttachment attachment, AtlasRegion region, bool updateUVs = true) {
			// (based on AtlasAttachmentLoader.cs)
			attachment.RendererObject = region;
			attachment.RegionU = region.u;
			attachment.RegionV = region.v;
			attachment.RegionU2 = region.u2;
			attachment.RegionV2 = region.v2;
			attachment.RegionRotate = region.rotate;
			attachment.regionOffsetX = region.offsetX;
			attachment.regionOffsetY = region.offsetY;
			attachment.regionWidth = region.width;
			attachment.regionHeight = region.height;
			attachment.regionOriginalWidth = region.originalWidth;
			attachment.regionOriginalHeight = region.originalHeight;

			if (updateUVs) attachment.UpdateUVs();
		}
	}
		
}