Your idea of merging multiple images into a larger texture and then using UV mapping to display them correctly in Spine is indeed feasible. Below is a step-by-step guide and implementation code to help you achieve this.
Step-by-Step Guide
- Merge Images into a Larger Texture: Combine your individual images into a single larger texture (
biggerTexture).
- Calculate UV Coordinates: Determine the UV coordinates for each image within the larger texture.
- Create RegionAttachment: Create a
RegionAttachment for each image and set its region to the corresponding part of the larger texture.
- Assign RegionAttachment to Spine: Assign the
RegionAttachment to the appropriate slot in your Spine skeleton.
Implementation Code
Here is a sample implementation in C# for Unity:
using UnityEngine;
using Spine;
using Spine.Unity;
public class SpineSkinChanger : MonoBehaviour
{
public SkeletonAnimation skeletonAnimation;
public Material sourceMaterial;
private Skin customSkin;
void Start()
{
customSkin = new Skin("customSkin");
skeletonAnimation.Skeleton.SetSkin(customSkin);
skeletonAnimation.Skeleton.SetSlotsToSetupPose();
}
public void ChangeAvatar(Texture2D biggerTexture, Rect[] uvRects, string strTargetSlot, string strTargetAttach)
{
int slotIndex = skeletonAnimation.Skeleton.Data.FindSlot(strTargetSlot).Index;
Attachment templateAttach = skeletonAnimation.Skeleton.Data.FindSkin("default").GetAttachment(slotIndex, strTargetAttach);
if (templateAttach is RegionAttachment regionAttachment)
{
for (int i = 0; i < uvRects.Length; i++)
{
Rect uvRect = uvRects[i];
RegionAttachment newAttachment = regionAttachment.GetRemappedClone(biggerTexture, sourceMaterial, uvRect);
customSkin.SetAttachment(slotIndex, strTargetAttach, newAttachment);
}
}
skeletonAnimation.Skeleton.SetAttachment(strTargetSlot, strTargetAttach);
}
}
public static class RegionAttachmentExtensions
{
public static RegionAttachment GetRemappedClone(this RegionAttachment original, Texture2D texture, Material material, Rect uvRect)
{
RegionAttachment newAttachment = new RegionAttachment(original.Name);
AtlasRegion region = new AtlasRegion
{
page = new AtlasPage { rendererObject = material },
u = uvRect.xMin,
v = uvRect.yMin,
u2 = uvRect.xMax,
v2 = uvRect.yMax,
width = (int)(uvRect.width * texture.width),
height = (int)(uvRect.height * texture.height),
originalWidth = (int)(uvRect.width * texture.width),
originalHeight = (int)(uvRect.height * texture.height),
offsetX = 0,
offsetY = 0,
rotate = false,
name = texture.name
};
newAttachment.SetRegion(region);
newAttachment.UpdateOffset();
return newAttachment;
}
}
Explanation
ChangeAvatar Method:
- Takes a
Texture2D (biggerTexture), an array of Rect (uvRects), and the target slot and attachment names.
- Finds the slot index and template attachment.
- Iterates through the
uvRects to create new RegionAttachment instances with the correct UV mapping.
- Sets the new attachment to the custom skin and updates the skeleton.
GetRemappedClone Extension Method:
- Creates a new
RegionAttachment and sets its region using the provided UV coordinates.
- Updates the offset to ensure the attachment is displayed correctly.
Summary
This code merges multiple images into a larger texture and uses UV mapping to display them correctly in Spine. The ChangeAvatar method updates the skeleton with the new attachments, ensuring the graphics are displayed as intended.
