[libgdx] Make sequence rendering thread-safe.

closes #2989

spine-libgdx/spine-libgdx-tests/src/com/esotericsoftware/spine/AnimationStateTests.java

@@ -36,7 +36,6 @@ import com.badlogic.gdx.Files.FileType;
 import com.badlogic.gdx.backends.lwjgl3.Lwjgl3FileHandle;
 import com.badlogic.gdx.math.MathUtils;
 import com.badlogic.gdx.utils.Array;
-import com.badlogic.gdx.utils.Null;
 import com.badlogic.gdx.utils.Pool;
 
 import com.esotericsoftware.spine.AnimationState.AnimationStateListener;
@@ -53,11 +52,11 @@ import com.esotericsoftware.spine.attachments.Sequence;
 /** Unit tests to ensure {@link AnimationState} is working as expected. */
 public class AnimationStateTests {
 	final SkeletonJson json = new SkeletonJson(new AttachmentLoader() {
-		public RegionAttachment newRegionAttachment (Skin skin, String name, String path, @Null Sequence sequence) {
+		public RegionAttachment newRegionAttachment (Skin skin, String name, String path, Sequence sequence) {
 			return null;
 		}
 
-		public MeshAttachment newMeshAttachment (Skin skin, String name, String path, @Null Sequence sequence) {
+		public MeshAttachment newMeshAttachment (Skin skin, String name, String path, Sequence sequence) {
 			return null;
 		}
 

spine-libgdx/spine-libgdx-tests/src/com/esotericsoftware/spine/BonePlotting.java

@@ -30,7 +30,6 @@
 package com.esotericsoftware.spine;
 
 import com.badlogic.gdx.files.FileHandle;
-import com.badlogic.gdx.utils.Null;
 
 import com.esotericsoftware.spine.Animation.MixBlend;
 import com.esotericsoftware.spine.Animation.MixDirection;
@@ -48,11 +47,11 @@ public class BonePlotting {
 	static public void main (String[] args) throws Exception {
 		// Create a skeleton loader that doesn't use an atlas and doesn't create any attachments.
 		SkeletonJson json = new SkeletonJson(new AttachmentLoader() {
-			public RegionAttachment newRegionAttachment (Skin skin, String name, String path, @Null Sequence sequence) {
+			public RegionAttachment newRegionAttachment (Skin skin, String name, String path, Sequence sequence) {
 				return null;
 			}
 
-			public MeshAttachment newMeshAttachment (Skin skin, String name, String path, @Null Sequence sequence) {
+			public MeshAttachment newMeshAttachment (Skin skin, String name, String path, Sequence sequence) {
 				return null;
 			}
 

spine-libgdx/spine-libgdx-tests/src/com/esotericsoftware/spine/Box2DExample.java

@@ -49,7 +49,6 @@ import com.badlogic.gdx.physics.box2d.FixtureDef;
 import com.badlogic.gdx.physics.box2d.PolygonShape;
 import com.badlogic.gdx.physics.box2d.World;
 import com.badlogic.gdx.utils.Array;
-import com.badlogic.gdx.utils.Null;
 import com.badlogic.gdx.utils.ScreenUtils;
 
 import com.esotericsoftware.spine.Animation.MixBlend;
@@ -88,12 +87,9 @@ public class Box2DExample extends ApplicationAdapter {
 		// This loader creates Box2dAttachments instead of RegionAttachments for an easy way to keep track of the Box2D body for
 		// each attachment.
 		AtlasAttachmentLoader atlasLoader = new AtlasAttachmentLoader(atlas) {
-			public RegionAttachment newRegionAttachment (Skin skin, String name, String path, @Null Sequence sequence) {
+			public RegionAttachment newRegionAttachment (Skin skin, String name, String path, Sequence sequence) {
-				Box2dAttachment attachment = new Box2dAttachment(name);
+				findRegions(name, path, sequence);
-				AtlasRegion region = atlas.findRegion(attachment.getName());
+				return new Box2dAttachment(name, sequence);
-				if (region == null) throw new RuntimeException("Region not found in atlas: " + attachment);
-				attachment.setRegion(region);
-				return attachment;
 			}
 		};
 		SkeletonJson json = new SkeletonJson(atlasLoader);
@@ -231,8 +227,8 @@ public class Box2DExample extends ApplicationAdapter {
 	static class Box2dAttachment extends RegionAttachment {
 		Body body;
 
-		public Box2dAttachment (String name) {
+		public Box2dAttachment (String name, Sequence sequence) {
-			super(name);
+			super(name, sequence);
 		}
 	}
 

spine-libgdx/spine-libgdx-tests/src/com/esotericsoftware/spine/utils/JsonWriter.java

@@ -4,7 +4,7 @@ package com.esotericsoftware.spine.utils;
 import java.util.Locale;
 
 public class JsonWriter {
-	private final StringBuffer buffer = new StringBuffer();
+	private final StringBuilder buffer = new StringBuilder();
 	private int depth = 0;
 	private boolean needsComma = false;
 

spine-libgdx/spine-libgdx-tests/src/com/esotericsoftware/spine/utils/SkeletonSerializer.java

@@ -2479,10 +2479,12 @@ public class SkeletonSerializer {
 		json.writeValue("MeshAttachment");
 
 		json.writeName("region");
-		if (obj.getRegion() == null) {
+		Sequence sequence = obj.getSequence();
+		TextureRegion region = sequence.getRegion(sequence.getSetupIndex());
+		if (region == null) {
 			json.writeNull();
 		} else {
-			writeTextureRegion(obj.getRegion());
+			writeTextureRegion(region);
 		}
 
 		json.writeName("triangles");
@@ -2501,8 +2503,10 @@ public class SkeletonSerializer {
 
 		json.writeName("uVs");
 		json.writeArrayStart();
-		for (float item : obj.getUVs()) {
+		float[] uvs = sequence.getUVs(sequence.getSetupIndex());
-			json.writeValue(item);
+		if (uvs != null) {
+			for (float item : uvs)
+				json.writeValue(item);
 		}
 		json.writeArrayEnd();
 
@@ -2954,24 +2958,32 @@ public class SkeletonSerializer {
 		json.writeName("type");
 		json.writeValue("RegionAttachment");
 
+		Sequence sequence = obj.getSequence();
+		int setupIndex = sequence.getSetupIndex();
+		TextureRegion region = sequence.getRegion(setupIndex);
+
 		json.writeName("region");
-		if (obj.getRegion() == null) {
+		if (region == null) {
 			json.writeNull();
 		} else {
-			writeTextureRegion(obj.getRegion());
+			writeTextureRegion(region);
 		}
 
 		json.writeName("offset");
 		json.writeArrayStart();
-		for (float item : obj.getOffset()) {
+		float[] offset = sequence.getOffsets(setupIndex);
-			json.writeValue(item);
+		if (offset != null) {
+			for (float item : offset)
+				json.writeValue(item);
 		}
 		json.writeArrayEnd();
 
 		json.writeName("uVs");
 		json.writeArrayStart();
-		for (float item : obj.getUVs()) {
+		float[] uvs = sequence.getUVs(setupIndex);
-			json.writeValue(item);
+		if (uvs != null) {
+			for (float item : uvs)
+				json.writeValue(item);
 		}
 		json.writeArrayEnd();
 
@@ -3003,11 +3015,7 @@ public class SkeletonSerializer {
 		json.writeValue(obj.getPath());
 
 		json.writeName("sequence");
-		if (obj.getSequence() == null) {
+		writeSequence(obj.getSequence());
-			json.writeNull();
-		} else {
-			writeSequence(obj.getSequence());
-		}
 
 		json.writeName("name");
 		json.writeValue(obj.getName());

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/Animation.java

@@ -43,7 +43,7 @@ import com.badlogic.gdx.utils.ObjectSet;
 
 import com.esotericsoftware.spine.BoneData.Inherit;
 import com.esotericsoftware.spine.attachments.Attachment;
-import com.esotericsoftware.spine.attachments.HasTextureRegion;
+import com.esotericsoftware.spine.attachments.HasSequence;
 import com.esotericsoftware.spine.attachments.Sequence;
 import com.esotericsoftware.spine.attachments.Sequence.SequenceMode;
 import com.esotericsoftware.spine.attachments.VertexAttachment;
@@ -1700,13 +1700,12 @@ public class Animation {
 		static private final int MODE = 1, DELAY = 2;
 
 		final int slotIndex;
-		final HasTextureRegion attachment;
+		final HasSequence attachment;
 
 		public SequenceTimeline (int frameCount, int slotIndex, Attachment attachment) {
-			super(frameCount,
+			super(frameCount, Property.sequence.ordinal() + "|" + slotIndex + "|" + ((HasSequence)attachment).getSequence().getId());
-				Property.sequence.ordinal() + "|" + slotIndex + "|" + ((HasTextureRegion)attachment).getSequence().getId());
 			this.slotIndex = slotIndex;
-			this.attachment = (HasTextureRegion)attachment;
+			this.attachment = (HasSequence)attachment;
 		}
 
 		public int getFrameEntries () {
@@ -1743,8 +1742,6 @@ public class Animation {
 				if (!(slotAttachment instanceof VertexAttachment vertexAttachment)
 					|| vertexAttachment.getTimelineAttachment() != attachment) return;
 			}
-			Sequence sequence = ((HasTextureRegion)slotAttachment).getSequence();
-			if (sequence == null) return;
 
 			if (direction == out) {
 				if (blend == setup) pose.setSequenceIndex(-1);
@@ -1762,7 +1759,7 @@ public class Animation {
 			int modeAndIndex = (int)frames[i + MODE];
 			float delay = frames[i + DELAY];
 
-			int index = modeAndIndex >> 4, count = sequence.getRegions().length;
+			int index = modeAndIndex >> 4, count = (((HasSequence)slotAttachment).getSequence()).getRegions().length;
 			SequenceMode mode = SequenceMode.values[modeAndIndex & 0xf];
 			if (mode != SequenceMode.hold) {
 				index += (time - before) / delay + 0.0001f;

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/Skeleton.java

@@ -495,7 +495,7 @@ public class Skeleton {
 				if (attachment instanceof RegionAttachment region) {
 					verticesLength = 8;
 					vertices = temp.setSize(8);
-					region.computeWorldVertices(slot, vertices, 0, 2);
+					region.computeWorldVertices(slot, region.getOffsets(slot.applied), vertices, 0, 2);
 					triangles = quadTriangles;
 				} else if (attachment instanceof MeshAttachment mesh) {
 					verticesLength = mesh.getWorldVerticesLength();

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/SkeletonBinary.java

@@ -475,7 +475,7 @@ public class SkeletonBinary extends SkeletonLoader {
 				if (parent == null) throw new SerializationException("Parent mesh not found: " + linkedMesh.parent);
 				linkedMesh.mesh.setTimelineAttachment(linkedMesh.inheritTimelines ? (VertexAttachment)parent : linkedMesh.mesh);
 				linkedMesh.mesh.setParentMesh((MeshAttachment)parent);
-				if (linkedMesh.mesh.getRegion() == null) linkedMesh.mesh.updateRegion();
+				linkedMesh.mesh.updateSequence();
 			}
 			linkedMeshes.clear();
 
@@ -561,7 +561,7 @@ public class SkeletonBinary extends SkeletonLoader {
 		case region -> {
 			String path = (flags & 16) != 0 ? input.readStringRef() : null;
 			int color = (flags & 32) != 0 ? input.readInt() : 0xffffffff;
-			Sequence sequence = (flags & 64) != 0 ? readSequence(input) : null;
+			Sequence sequence = readSequence(input, (flags & 64) != 0);
 			float rotation = (flags & 128) != 0 ? input.readFloat() : 0;
 			float x = input.readFloat();
 			float y = input.readFloat();
@@ -582,8 +582,7 @@ public class SkeletonBinary extends SkeletonLoader {
 			region.setWidth(width * scale);
 			region.setHeight(height * scale);
 			Color.rgba8888ToColor(region.getColor(), color);
-			region.setSequence(sequence);
+			region.updateSequence();
-			if (region.getRegion() != null) region.updateRegion();
 			yield region;
 		}
 		case boundingbox -> {
@@ -601,7 +600,7 @@ public class SkeletonBinary extends SkeletonLoader {
 		case mesh -> {
 			String path = (flags & 16) != 0 ? input.readStringRef() : name;
 			int color = (flags & 32) != 0 ? input.readInt() : 0xffffffff;
-			Sequence sequence = (flags & 64) != 0 ? readSequence(input) : null;
+			Sequence sequence = readSequence(input, (flags & 64) != 0);
 			int hullLength = input.readInt(true);
 			Vertices vertices = readVertices(input, (flags & 128) != 0);
 			float[] uvs = readFloatArray(input, vertices.length, 1);
@@ -619,25 +618,24 @@ public class SkeletonBinary extends SkeletonLoader {
 			if (mesh == null) yield null;
 			mesh.setPath(path);
 			Color.rgba8888ToColor(mesh.getColor(), color);
+			mesh.setHullLength(hullLength << 1);
 			mesh.setBones(vertices.bones);
 			mesh.setVertices(vertices.vertices);
 			mesh.setWorldVerticesLength(vertices.length);
-			mesh.setTriangles(triangles);
 			mesh.setRegionUVs(uvs);
-			if (mesh.getRegion() != null) mesh.updateRegion();
+			mesh.setTriangles(triangles);
-			mesh.setHullLength(hullLength << 1);
-			mesh.setSequence(sequence);
 			if (nonessential) {
 				mesh.setEdges(edges);
 				mesh.setWidth(width * scale);
 				mesh.setHeight(height * scale);
 			}
+			mesh.updateSequence();
 			yield mesh;
 		}
 		case linkedmesh -> {
 			String path = (flags & 16) != 0 ? input.readStringRef() : name;
 			int color = (flags & 32) != 0 ? input.readInt() : 0xffffffff;
-			Sequence sequence = (flags & 64) != 0 ? readSequence(input) : null;
+			Sequence sequence = readSequence(input, (flags & 64) != 0);
 			boolean inheritTimelines = (flags & 128) != 0;
 			int skinIndex = input.readInt(true);
 			String parent = input.readStringRef();
@@ -651,7 +649,6 @@ public class SkeletonBinary extends SkeletonLoader {
 			if (mesh == null) yield null;
 			mesh.setPath(path);
 			Color.rgba8888ToColor(mesh.getColor(), color);
-			mesh.setSequence(sequence);
 			if (nonessential) {
 				mesh.setWidth(width * scale);
 				mesh.setHeight(height * scale);
@@ -711,8 +708,9 @@ public class SkeletonBinary extends SkeletonLoader {
 		};
 	}
 
-	private Sequence readSequence (SkeletonInput input) throws IOException {
+	private Sequence readSequence (SkeletonInput input, boolean hasPathSuffix) throws IOException {
-		var sequence = new Sequence(input.readInt(true));
+		if (!hasPathSuffix) return new Sequence(1, false);
+		var sequence = new Sequence(input.readInt(true), true);
 		sequence.setStart(input.readInt(true));
 		sequence.setDigits(input.readInt(true));
 		sequence.setSetupIndex(input.readInt(true));

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/SkeletonJson.java

@@ -492,7 +492,7 @@ public class SkeletonJson extends SkeletonLoader {
 				if (parent == null) throw new SerializationException("Parent mesh not found: " + linkedMesh.parent);
 				linkedMesh.mesh.setTimelineAttachment(linkedMesh.inheritTimelines ? (VertexAttachment)parent : linkedMesh.mesh);
 				linkedMesh.mesh.setParentMesh((MeshAttachment)parent);
-				if (linkedMesh.mesh.getRegion() != null) linkedMesh.mesh.updateRegion();
+				linkedMesh.mesh.updateSequence();
 			}
 			linkedMeshes.clear();
 
@@ -580,12 +580,11 @@ public class SkeletonJson extends SkeletonLoader {
 			region.setRotation(map.getFloat("rotation", 0));
 			region.setWidth(map.getFloat("width") * scale);
 			region.setHeight(map.getFloat("height") * scale);
-			region.setSequence(sequence);
 
 			String color = map.getString("color", null);
 			if (color != null) Color.valueOf(color, region.getColor());
 
-			if (region.getRegion() != null) region.updateRegion();
+			region.updateSequence();
 			yield region;
 		}
 		case boundingbox -> {
@@ -609,7 +608,6 @@ public class SkeletonJson extends SkeletonLoader {
 
 			mesh.setWidth(map.getFloat("width", 0) * scale);
 			mesh.setHeight(map.getFloat("height", 0) * scale);
-			mesh.setSequence(sequence);
 
 			String parent = map.getString("parent", null);
 			if (parent != null) {
@@ -622,10 +620,11 @@ public class SkeletonJson extends SkeletonLoader {
 			readVertices(map, mesh, uvs.length);
 			mesh.setTriangles(map.require("triangles").asShortArray());
 			mesh.setRegionUVs(uvs);
-			if (mesh.getRegion() != null) mesh.updateRegion();
 
 			if (map.has("hull")) mesh.setHullLength(map.require("hull").asInt() << 1);
 			if (map.has("edges")) mesh.setEdges(map.require("edges").asShortArray());
+
+			mesh.updateSequence();
 			yield mesh;
 		}
 		case path -> {
@@ -680,8 +679,8 @@ public class SkeletonJson extends SkeletonLoader {
 	}
 
 	private Sequence readSequence (@Null JsonValue map) {
-		if (map == null) return null;
+		if (map == null) return new Sequence(1, false);
-		var sequence = new Sequence(map.getInt("count"));
+		var sequence = new Sequence(map.getInt("count"), true);
 		sequence.setStart(map.getInt("start", 1));
 		sequence.setDigits(map.getInt("digits", 0));
 		sequence.setSetupIndex(map.getInt("setup", 0));

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/SkeletonRenderer.java

@@ -41,6 +41,7 @@ import com.esotericsoftware.spine.attachments.Attachment;
 import com.esotericsoftware.spine.attachments.ClippingAttachment;
 import com.esotericsoftware.spine.attachments.MeshAttachment;
 import com.esotericsoftware.spine.attachments.RegionAttachment;
+import com.esotericsoftware.spine.attachments.Sequence;
 import com.esotericsoftware.spine.attachments.SkeletonAttachment;
 import com.esotericsoftware.spine.utils.SkeletonClipping;
 import com.esotericsoftware.spine.utils.TwoColorPolygonBatch;
@@ -83,7 +84,11 @@ public class SkeletonRenderer {
 			SlotPose pose = slot.applied;
 			Attachment attachment = pose.attachment;
 			if (attachment instanceof RegionAttachment region) {
-				region.computeWorldVertices(slot, vertices, 0, 5);
+				Sequence sequence = region.getSequence();
+				int sequenceIndex = sequence.resolveIndex(pose);
+				Texture texture = sequence.getRegion(sequenceIndex).getTexture();
+				float[] uvs = sequence.getUVs(sequenceIndex);
+				region.computeWorldVertices(slot, sequence.getOffsets(sequenceIndex), vertices, 0, 5);
 				Color color = region.getColor(), slotColor = pose.getColor();
 				float alpha = a * slotColor.a * color.a * 255;
 				float multiplier = pmaColors ? alpha : 255;
@@ -102,14 +107,13 @@ public class SkeletonRenderer {
 					| (int)(b * slotColor.b * color.b * multiplier) << 16 //
 					| (int)(g * slotColor.g * color.g * multiplier) << 8 //
 					| (int)(r * slotColor.r * color.r * multiplier));
-				float[] uvs = region.getUVs();
 				for (int u = 0, v = 2; u < 8; u += 2, v += 5) {
 					vertices[v] = c;
 					vertices[v + 1] = uvs[u];
 					vertices[v + 2] = uvs[u + 1];
 				}
 
-				batch.draw(region.getRegion().getTexture(), vertices, 0, 20);
+				batch.draw(texture, vertices, 0, 20);
 
 			} else if (attachment instanceof ClippingAttachment) {
 				throw new RuntimeException(batch.getClass().getSimpleName()
@@ -153,10 +157,12 @@ public class SkeletonRenderer {
 					if (attachment instanceof RegionAttachment region) {
 						verticesLength = 20;
 						vertices = this.vertices.items;
-						region.computeWorldVertices(slot, vertices, 0, 5);
+						Sequence sequence = region.getSequence();
+						int sequenceIndex = sequence.resolveIndex(pose);
+						region.computeWorldVertices(slot, sequence.getOffsets(sequenceIndex), vertices, 0, 5);
 						triangles = quadTriangles;
-						texture = region.getRegion().getTexture();
+						texture = sequence.getRegion(sequenceIndex).getTexture();
-						uvs = region.getUVs();
+						uvs = sequence.getUVs(sequenceIndex);
 						color = region.getColor();
 
 					} else if (attachment instanceof MeshAttachment mesh) {
@@ -165,8 +171,10 @@ public class SkeletonRenderer {
 						vertices = this.vertices.setSize(verticesLength);
 						mesh.computeWorldVertices(skeleton, slot, 0, count, vertices, 0, 5);
 						triangles = mesh.getTriangles();
-						texture = mesh.getRegion().getTexture();
+						Sequence sequence = mesh.getSequence();
-						uvs = mesh.getUVs();
+						int sequenceIndex = sequence.resolveIndex(pose);
+						texture = sequence.getRegion(sequenceIndex).getTexture();
+						uvs = sequence.getUVs(sequenceIndex);
 						color = mesh.getColor();
 
 					} else if (attachment instanceof ClippingAttachment clip) {
@@ -248,10 +256,12 @@ public class SkeletonRenderer {
 					if (attachment instanceof RegionAttachment region) {
 						verticesLength = 24;
 						vertices = this.vertices.items;
-						region.computeWorldVertices(slot, vertices, 0, 6);
+						Sequence sequence = region.getSequence();
+						int sequenceIndex = sequence.resolveIndex(pose);
+						region.computeWorldVertices(slot, sequence.getOffsets(sequenceIndex), vertices, 0, 6);
 						triangles = quadTriangles;
-						texture = region.getRegion().getTexture();
+						texture = sequence.getRegion(sequenceIndex).getTexture();
-						uvs = region.getUVs();
+						uvs = sequence.getUVs(sequenceIndex);
 						color = region.getColor();
 
 					} else if (attachment instanceof MeshAttachment mesh) {
@@ -260,8 +270,10 @@ public class SkeletonRenderer {
 						vertices = this.vertices.setSize(verticesLength);
 						mesh.computeWorldVertices(skeleton, slot, 0, count, vertices, 0, 6);
 						triangles = mesh.getTriangles();
-						texture = mesh.getRegion().getTexture();
+						Sequence sequence = mesh.getSequence();
-						uvs = mesh.getUVs();
+						int sequenceIndex = sequence.resolveIndex(pose);
+						texture = sequence.getRegion(sequenceIndex).getTexture();
+						uvs = sequence.getUVs(sequenceIndex);
 						color = mesh.getColor();
 
 					} else if (attachment instanceof ClippingAttachment clip) {

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/SkeletonRendererDebug.java

@@ -126,7 +126,8 @@ public class SkeletonRendererDebug {
 				if (!slot.bone.active) continue;
 				if (slot.pose.attachment instanceof RegionAttachment region) {
 					float[] vertices = this.vertices.items;
-					region.computeWorldVertices(slot, vertices, 0, 2);
+					float[] offsets = region.getOffsets(slot.applied);
+					region.computeWorldVertices(slot, offsets, vertices, 0, 2);
 					shapes.line(vertices[0], vertices[1], vertices[2], vertices[3]);
 					shapes.line(vertices[2], vertices[3], vertices[4], vertices[5]);
 					shapes.line(vertices[4], vertices[5], vertices[6], vertices[7]);

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/attachments/AtlasAttachmentLoader.java

@@ -32,7 +32,6 @@ package com.esotericsoftware.spine.attachments;
 import com.badlogic.gdx.graphics.g2d.TextureAtlas;
 import com.badlogic.gdx.graphics.g2d.TextureAtlas.AtlasRegion;
 import com.badlogic.gdx.graphics.g2d.TextureRegion;
-import com.badlogic.gdx.utils.Null;
 
 import com.esotericsoftware.spine.Skin;
 
@@ -55,40 +54,27 @@ public class AtlasAttachmentLoader implements AttachmentLoader {
 		this.allowMissingRegions = allowMissingRegions;
 	}
 
-	private void loadSequence (String name, String basePath, Sequence sequence) {
+	protected void findRegions (String name, String basePath, Sequence sequence) {
 		TextureRegion[] regions = sequence.getRegions();
-		for (int i = 0, n = regions.length; i < n; i++) {
+		for (int i = 0, n = regions.length; i < n; i++)
-			String path = sequence.getPath(basePath, i);
+			regions[i] = findRegion(name, sequence.getPath(basePath, i));
-			regions[i] = atlas.findRegion(path);
-			if (regions[i] == null && !allowMissingRegions)
-				throw new RuntimeException("Region not found in atlas: " + path + " (sequence: " + name + ")");
-		}
 	}
 
-	public RegionAttachment newRegionAttachment (Skin skin, String name, String path, @Null Sequence sequence) {
+	protected AtlasRegion findRegion (String name, String path) {
-		var attachment = new RegionAttachment(name);
+		AtlasRegion region = atlas.findRegion(path);
-		if (sequence != null)
+		if (region == null && !allowMissingRegions)
-			loadSequence(name, path, sequence);
+			throw new RuntimeException("Region not found in atlas: " + path + " (attachment: " + name + ")");
-		else {
+		return region;
-			AtlasRegion region = atlas.findRegion(path);
-			if (region == null && !allowMissingRegions)
-				throw new RuntimeException("Region not found in atlas: " + path + " (region attachment: " + name + ")");
-			attachment.setRegion(region);
-		}
-		return attachment;
 	}
 
-	public MeshAttachment newMeshAttachment (Skin skin, String name, String path, @Null Sequence sequence) {
+	public RegionAttachment newRegionAttachment (Skin skin, String name, String path, Sequence sequence) {
-		var attachment = new MeshAttachment(name);
+		findRegions(name, path, sequence);
-		if (sequence != null)
+		return new RegionAttachment(name, sequence);
-			loadSequence(name, path, sequence);
+	}
-		else {
+
-			AtlasRegion region = atlas.findRegion(path);
+	public MeshAttachment newMeshAttachment (Skin skin, String name, String path, Sequence sequence) {
-			if (region == null && !allowMissingRegions)
+		findRegions(name, path, sequence);
-				throw new RuntimeException("Region not found in atlas: " + path + " (mesh attachment: " + name + ")");
+		return new MeshAttachment(name, sequence);
-			attachment.setRegion(region);
-		}
-		return attachment;
 	}
 
 	public BoundingBoxAttachment newBoundingBoxAttachment (Skin skin, String name) {

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/attachments/AttachmentLoader.java

@@ -39,10 +39,10 @@ import com.esotericsoftware.spine.Skin;
  * Runtimes Guide. */
 public interface AttachmentLoader {
 	/** @return May be null to not load the attachment. */
-	public @Null RegionAttachment newRegionAttachment (Skin skin, String name, String path, @Null Sequence sequence);
+	public @Null RegionAttachment newRegionAttachment (Skin skin, String name, String path, Sequence sequence);
 
 	/** @return May be null to not load the attachment. In that case null should also be returned for child meshes. */
-	public @Null MeshAttachment newMeshAttachment (Skin skin, String name, String path, @Null Sequence sequence);
+	public @Null MeshAttachment newMeshAttachment (Skin skin, String name, String path, Sequence sequence);
 
 	/** @return May be null to not load the attachment. */
 	public @Null BoundingBoxAttachment newBoundingBoxAttachment (Skin skin, String name);

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/attachments/HasSequence.java

@@ -30,29 +30,16 @@
 package com.esotericsoftware.spine.attachments;
 
 import com.badlogic.gdx.graphics.Color;
-import com.badlogic.gdx.graphics.g2d.TextureRegion;
-import com.badlogic.gdx.utils.Null;
 
-public interface HasTextureRegion {
+public interface HasSequence {
-	/** The name used to find the {@link #getRegion()}. */
 	public String getPath ();
 
 	public void setPath (String path);
 
-	public TextureRegion getRegion ();
-
-	/** Sets the region used to draw the attachment. After setting the region or if the region's properties are changed,
-	 * {@link #updateRegion()} must be called. */
-	public void setRegion (TextureRegion region);
-
-	/** Updates any values the attachment calculates using the {@link #getRegion()}. Must be called after setting the
-	 * {@link #getRegion()} or if the region's properties are changed. */
-	public void updateRegion ();
-
-	/** The color to tint the attachment. */
 	public Color getColor ();
 
-	public @Null Sequence getSequence ();
+	/** Calls {@link Sequence#update(HasSequence)} on this attachment's sequence. */
+	public void updateSequence ();
 
-	public void setSequence (@Null Sequence sequence);
+	public Sequence getSequence ();
 }

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/attachments/MeshAttachment.java

@@ -36,29 +36,27 @@ import com.badlogic.gdx.graphics.g2d.TextureAtlas.AtlasRegion;
 import com.badlogic.gdx.graphics.g2d.TextureRegion;
 import com.badlogic.gdx.utils.Null;
 
-import com.esotericsoftware.spine.Skeleton;
-import com.esotericsoftware.spine.Slot;
-
 /** An attachment that displays a textured mesh. A mesh has hull vertices and internal vertices within the hull. Holes are not
  * supported. Each vertex has UVs (texture coordinates) and triangles are used to map an image on to the mesh.
  * <p>
  * See <a href="https://esotericsoftware.com/spine-meshes">Mesh attachments</a> in the Spine User Guide. */
-public class MeshAttachment extends VertexAttachment implements HasTextureRegion {
+public class MeshAttachment extends VertexAttachment implements HasSequence {
-	private TextureRegion region;
+	private final Sequence sequence;
-	private String path;
+	float[] regionUVs;
-	private float[] regionUVs, uvs;
 	private short[] triangles;
-	private final Color color = new Color(1, 1, 1, 1);
 	private int hullLength;
+	private String path;
+	private final Color color = new Color(1, 1, 1, 1);
 	private @Null MeshAttachment parentMesh;
-	private @Null Sequence sequence;
 
 	// Nonessential.
 	private @Null short[] edges;
 	private float width, height;
 
-	public MeshAttachment (String name) {
+	public MeshAttachment (String name, Sequence sequence) {
 		super(name);
+		if (sequence == null) throw new IllegalArgumentException("sequence cannot be null.");
+		this.sequence = sequence;
 	}
 
 	/** Copy constructor. Use {@link #newLinkedMesh()} if the other mesh is a linked mesh. */
@@ -67,21 +65,17 @@ public class MeshAttachment extends VertexAttachment implements HasTextureRegion
 
 		if (parentMesh != null) throw new IllegalArgumentException("Use newLinkedMesh to copy a linked mesh.");
 
-		region = other.region;
 		path = other.path;
 		color.set(other.color);
 
 		regionUVs = new float[other.regionUVs.length];
 		arraycopy(other.regionUVs, 0, regionUVs, 0, regionUVs.length);
 
-		uvs = new float[other.uvs.length];
-		arraycopy(other.uvs, 0, uvs, 0, uvs.length);
-
 		triangles = new short[other.triangles.length];
 		arraycopy(other.triangles, 0, triangles, 0, triangles.length);
 
 		hullLength = other.hullLength;
-		sequence = other.sequence != null ? new Sequence(other.sequence) : null;
+		sequence = new Sequence(other.sequence);
 
 		// Nonessential.
 		if (other.edges != null) {
@@ -92,99 +86,6 @@ public class MeshAttachment extends VertexAttachment implements HasTextureRegion
 		height = other.height;
 	}
 
-	public void setRegion (TextureRegion region) {
-		if (region == null) throw new IllegalArgumentException("region cannot be null.");
-		this.region = region;
-	}
-
-	public @Null TextureRegion getRegion () {
-		return region;
-	}
-
-	/** Calculates {@link #uvs} using the {@link #regionUVs} and region. Must be called if the region, the region's properties, or
-	 * the {@link #regionUVs} are changed. */
-	public void updateRegion () {
-		float[] regionUVs = this.regionUVs;
-		if (this.uvs == null || this.uvs.length != regionUVs.length) this.uvs = new float[regionUVs.length];
-		float[] uvs = this.uvs;
-		int n = uvs.length;
-		float u, v, width, height;
-		if (region instanceof AtlasRegion region) {
-			u = region.getU();
-			v = region.getV();
-			float textureWidth = region.getTexture().getWidth(), textureHeight = region.getTexture().getHeight();
-			switch (region.degrees) {
-			case 90 -> {
-				u -= (region.originalHeight - region.offsetY - region.packedWidth) / textureWidth;
-				v -= (region.originalWidth - region.offsetX - region.packedHeight) / textureHeight;
-				width = region.originalHeight / textureWidth;
-				height = region.originalWidth / textureHeight;
-				for (int i = 0; i < n; i += 2) {
-					uvs[i] = u + regionUVs[i + 1] * width;
-					uvs[i + 1] = v + (1 - regionUVs[i]) * height;
-				}
-				return;
-			}
-			case 180 -> {
-				u -= (region.originalWidth - region.offsetX - region.packedWidth) / textureWidth;
-				v -= region.offsetY / textureHeight;
-				width = region.originalWidth / textureWidth;
-				height = region.originalHeight / textureHeight;
-				for (int i = 0; i < n; i += 2) {
-					uvs[i] = u + (1 - regionUVs[i]) * width;
-					uvs[i + 1] = v + (1 - regionUVs[i + 1]) * height;
-				}
-				return;
-			}
-			case 270 -> {
-				u -= region.offsetY / textureWidth;
-				v -= region.offsetX / textureHeight;
-				width = region.originalHeight / textureWidth;
-				height = region.originalWidth / textureHeight;
-				for (int i = 0; i < n; i += 2) {
-					uvs[i] = u + (1 - regionUVs[i + 1]) * width;
-					uvs[i + 1] = v + regionUVs[i] * height;
-				}
-				return;
-			}
-			default -> {
-				u -= region.offsetX / textureWidth;
-				v -= (region.originalHeight - region.offsetY - region.packedHeight) / textureHeight;
-				width = region.originalWidth / textureWidth;
-				height = region.originalHeight / textureHeight;
-			}
-			}
-		} else if (region == null) {
-			u = v = 0;
-			width = height = 1;
-		} else {
-			u = region.getU();
-			v = region.getV();
-			width = region.getU2() - u;
-			height = region.getV2() - v;
-		}
-		for (int i = 0; i < n; i += 2) {
-			uvs[i] = u + regionUVs[i] * width;
-			uvs[i + 1] = v + regionUVs[i + 1] * height;
-		}
-	}
-
-	/** If the attachment has a {@link #sequence}, the region may be changed. */
-	public void computeWorldVertices (Skeleton skeleton, Slot slot, int start, int count, float[] worldVertices, int offset,
-		int stride) {
-		if (sequence != null) sequence.apply(slot.getAppliedPose(), this);
-		super.computeWorldVertices(skeleton, slot, start, count, worldVertices, offset, stride);
-	}
-
-	/** Triplets of vertex indices which describe the mesh's triangulation. */
-	public short[] getTriangles () {
-		return triangles;
-	}
-
-	public void setTriangles (short[] triangles) {
-		this.triangles = triangles;
-	}
-
 	/** The UV pair for each vertex, normalized within the texture region. */
 	public float[] getRegionUVs () {
 		return regionUVs;
@@ -195,27 +96,13 @@ public class MeshAttachment extends VertexAttachment implements HasTextureRegion
 		this.regionUVs = regionUVs;
 	}
 
-	/** The UV pair for each vertex, normalized within the entire texture.
+	/** Triplets of vertex indices which describe the mesh's triangulation. */
-	 * <p>
+	public short[] getTriangles () {
-	 * See {@link #updateRegion()}. */
+		return triangles;
-	public float[] getUVs () {
-		return uvs;
 	}
 
-	public void setUVs (float[] uvs) {
+	public void setTriangles (short[] triangles) {
-		this.uvs = uvs;
+		this.triangles = triangles;
-	}
-
-	public Color getColor () {
-		return color;
-	}
-
-	public String getPath () {
-		return path;
-	}
-
-	public void setPath (String path) {
-		this.path = path;
 	}
 
 	/** The number of entries at the beginning of {@link #vertices} that make up the mesh hull. */
@@ -227,12 +114,32 @@ public class MeshAttachment extends VertexAttachment implements HasTextureRegion
 		this.hullLength = hullLength;
 	}
 
+	public Sequence getSequence () {
+		return sequence;
+	}
+
+	public void updateSequence () {
+		sequence.update(this);
+	}
+
+	public String getPath () {
+		return path;
+	}
+
+	public void setPath (String path) {
+		this.path = path;
+	}
+
+	public Color getColor () {
+		return color;
+	}
+
 	public void setEdges (short[] edges) {
 		this.edges = edges;
 	}
 
 	/** Vertex index pairs describing edges for controlling triangulation, or be null if nonessential data was not exported. Mesh
-	 * triangles will never cross edges. Triangulation is not performed at runtime. */
+	 * triangles never cross edges. Triangulation is not performed at runtime. */
 	public @Null short[] getEdges () {
 		return edges;
 	}
@@ -255,14 +162,6 @@ public class MeshAttachment extends VertexAttachment implements HasTextureRegion
 		this.height = height;
 	}
 
-	public @Null Sequence getSequence () {
-		return sequence;
-	}
-
-	public void setSequence (@Null Sequence sequence) {
-		this.sequence = sequence;
-	}
-
 	/** The parent mesh if this is a linked mesh, else null. A linked mesh shares the {@link #bones}, {@link #vertices},
 	 * {@link #regionUVs}, {@link #triangles}, {@link #hullLength}, {@link #edges}, {@link #width}, and {@link #height} with the
 	 * parent mesh, but may have a different {@link #name} or {@link #path} (and therefore a different texture). */
@@ -287,17 +186,81 @@ public class MeshAttachment extends VertexAttachment implements HasTextureRegion
 
 	/** Returns a new mesh with the {@link #parentMesh} set to this mesh's parent mesh, if any, else to this mesh. */
 	public MeshAttachment newLinkedMesh () {
-		var mesh = new MeshAttachment(name);
+		var mesh = new MeshAttachment(name, new Sequence(sequence));
 		mesh.timelineAttachment = timelineAttachment;
-		mesh.region = region;
 		mesh.path = path;
 		mesh.color.set(color);
 		mesh.setParentMesh(parentMesh != null ? parentMesh : this);
-		if (mesh.getRegion() != null) mesh.updateRegion();
+		mesh.updateSequence();
 		return mesh;
 	}
 
 	public MeshAttachment copy () {
 		return parentMesh != null ? newLinkedMesh() : new MeshAttachment(this);
 	}
+
+	/** Computes {@link Sequence#getUVs(int) UVs} for a mesh attachment.
+	 * @param uvs Output array for the computed UVs, same length as regionUVs. */
+	static void computeUVs (@Null TextureRegion region, float[] regionUVs, float[] uvs) {
+		int n = uvs.length;
+		float u, v, width, height;
+		if (region instanceof AtlasRegion r) {
+			u = r.getU();
+			v = r.getV();
+			float textureWidth = r.getTexture().getWidth(), textureHeight = r.getTexture().getHeight();
+			switch (r.degrees) {
+			case 90 -> {
+				u -= (r.originalHeight - r.offsetY - r.packedWidth) / textureWidth;
+				v -= (r.originalWidth - r.offsetX - r.packedHeight) / textureHeight;
+				width = r.originalHeight / textureWidth;
+				height = r.originalWidth / textureHeight;
+				for (int i = 0; i < n; i += 2) {
+					uvs[i] = u + regionUVs[i + 1] * width;
+					uvs[i + 1] = v + (1 - regionUVs[i]) * height;
+				}
+				return;
+			}
+			case 180 -> {
+				u -= (r.originalWidth - r.offsetX - r.packedWidth) / textureWidth;
+				v -= r.offsetY / textureHeight;
+				width = r.originalWidth / textureWidth;
+				height = r.originalHeight / textureHeight;
+				for (int i = 0; i < n; i += 2) {
+					uvs[i] = u + (1 - regionUVs[i]) * width;
+					uvs[i + 1] = v + (1 - regionUVs[i + 1]) * height;
+				}
+				return;
+			}
+			case 270 -> {
+				u -= r.offsetY / textureWidth;
+				v -= r.offsetX / textureHeight;
+				width = r.originalHeight / textureWidth;
+				height = r.originalWidth / textureHeight;
+				for (int i = 0; i < n; i += 2) {
+					uvs[i] = u + (1 - regionUVs[i + 1]) * width;
+					uvs[i + 1] = v + regionUVs[i] * height;
+				}
+				return;
+			}
+			default -> {
+				u -= r.offsetX / textureWidth;
+				v -= (r.originalHeight - r.offsetY - r.packedHeight) / textureHeight;
+				width = r.originalWidth / textureWidth;
+				height = r.originalHeight / textureHeight;
+			}
+			}
+		} else if (region == null) {
+			u = v = 0;
+			width = height = 1;
+		} else {
+			u = region.getU();
+			v = region.getV();
+			width = region.getU2() - u;
+			height = region.getV2() - v;
+		}
+		for (int i = 0; i < n; i += 2) {
+			uvs[i] = u + regionUVs[i] * width;
+			uvs[i + 1] = v + regionUVs[i + 1] * height;
+		}
+	}
 }

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/attachments/RegionAttachment.java

@@ -38,32 +38,31 @@ import com.badlogic.gdx.utils.Null;
 
 import com.esotericsoftware.spine.BonePose;
 import com.esotericsoftware.spine.Slot;
+import com.esotericsoftware.spine.SlotPose;
 
 /** An attachment that displays a textured quadrilateral.
  * <p>
  * See <a href="https://esotericsoftware.com/spine-regions">Region attachments</a> in the Spine User Guide. */
-public class RegionAttachment extends Attachment implements HasTextureRegion {
+public class RegionAttachment extends Attachment implements HasSequence {
 	static public final int BLX = 0, BLY = 1;
 	static public final int ULX = 2, ULY = 3;
 	static public final int URX = 4, URY = 5;
 	static public final int BRX = 6, BRY = 7;
 
-	private TextureRegion region;
+	private final Sequence sequence;
+	float x, y, scaleX = 1, scaleY = 1, rotation, width, height;
 	private String path;
-	private float x, y, scaleX = 1, scaleY = 1, rotation, width, height;
-	private final float[] uvs = new float[8];
-	private final float[] offset = new float[8];
 	private final Color color = new Color(1, 1, 1, 1);
-	private @Null Sequence sequence;
 
-	public RegionAttachment (String name) {
+	public RegionAttachment (String name, Sequence sequence) {
 		super(name);
+		if (sequence == null) throw new IllegalArgumentException("sequence cannot be null.");
+		this.sequence = sequence;
 	}
 
 	/** Copy constructor. */
 	protected RegionAttachment (RegionAttachment other) {
 		super(other);
-		region = other.region;
 		path = other.path;
 		x = other.x;
 		y = other.y;
@@ -72,148 +71,50 @@ public class RegionAttachment extends Attachment implements HasTextureRegion {
 		rotation = other.rotation;
 		width = other.width;
 		height = other.height;
-		arraycopy(other.uvs, 0, uvs, 0, 8);
-		arraycopy(other.offset, 0, offset, 0, 8);
 		color.set(other.color);
-		sequence = other.sequence != null ? new Sequence(other.sequence) : null;
+		sequence = new Sequence(other.sequence);
 	}
 
-	/** Calculates the {@link #offset} and {@link #uvs} using the region and the attachment's transform. Must be called if the
+	/** Transforms the attachment's four vertices to world coordinates.
-	 * region, the region's properties, or the transform are changed. */
-	public void updateRegion () {
-		float width = getWidth(), height = getHeight();
-		float localX2 = width / 2;
-		float localY2 = height / 2;
-		float localX = -localX2;
-		float localY = -localY2;
-		boolean rotated = false;
-		if (region instanceof AtlasRegion region) {
-			localX += region.offsetX / region.originalWidth * width;
-			localY += region.offsetY / region.originalHeight * height;
-			if (region.degrees == 90) {
-				rotated = true;
-				localX2 -= (region.originalWidth - region.offsetX - region.packedHeight) / region.originalWidth * width;
-				localY2 -= (region.originalHeight - region.offsetY - region.packedWidth) / region.originalHeight * height;
-			} else {
-				localX2 -= (region.originalWidth - region.offsetX - region.packedWidth) / region.originalWidth * width;
-				localY2 -= (region.originalHeight - region.offsetY - region.packedHeight) / region.originalHeight * height;
-			}
-		}
-		float scaleX = getScaleX(), scaleY = getScaleY();
-		localX *= scaleX;
-		localY *= scaleY;
-		localX2 *= scaleX;
-		localY2 *= scaleY;
-		float r = getRotation() * degRad, cos = cos(r), sin = sin(r);
-		float x = getX(), y = getY();
-		float localXCos = localX * cos + x;
-		float localXSin = localX * sin;
-		float localYCos = localY * cos + y;
-		float localYSin = localY * sin;
-		float localX2Cos = localX2 * cos + x;
-		float localX2Sin = localX2 * sin;
-		float localY2Cos = localY2 * cos + y;
-		float localY2Sin = localY2 * sin;
-		float[] offset = this.offset;
-		offset[BLX] = localXCos - localYSin;
-		offset[BLY] = localYCos + localXSin;
-		offset[ULX] = localXCos - localY2Sin;
-		offset[ULY] = localY2Cos + localXSin;
-		offset[URX] = localX2Cos - localY2Sin;
-		offset[URY] = localY2Cos + localX2Sin;
-		offset[BRX] = localX2Cos - localYSin;
-		offset[BRY] = localYCos + localX2Sin;
-
-		float[] uvs = this.uvs;
-		if (region == null) {
-			uvs[BLX] = 0;
-			uvs[BLY] = 0;
-			uvs[ULX] = 0;
-			uvs[ULY] = 1;
-			uvs[URX] = 1;
-			uvs[URY] = 1;
-			uvs[BRX] = 1;
-			uvs[BRY] = 0;
-		} else if (rotated) {
-			uvs[BLX] = region.getU2();
-			uvs[BLY] = region.getV();
-			uvs[ULX] = region.getU2();
-			uvs[ULY] = region.getV2();
-			uvs[URX] = region.getU();
-			uvs[URY] = region.getV2();
-			uvs[BRX] = region.getU();
-			uvs[BRY] = region.getV();
-		} else {
-			uvs[BLX] = region.getU2();
-			uvs[BLY] = region.getV2();
-			uvs[ULX] = region.getU();
-			uvs[ULY] = region.getV2();
-			uvs[URX] = region.getU();
-			uvs[URY] = region.getV();
-			uvs[BRX] = region.getU2();
-			uvs[BRY] = region.getV();
-		}
-	}
-
-	public void setRegion (TextureRegion region) {
-		if (region == null) throw new IllegalArgumentException("region cannot be null.");
-		this.region = region;
-	}
-
-	public @Null TextureRegion getRegion () {
-		return region;
-	}
-
-	/** Transforms the attachment's four vertices to world coordinates. If the attachment has a {@link #sequence}, the region may
-	 * be changed.
 	 * <p>
 	 * See <a href="https://esotericsoftware.com/spine-runtime-skeletons#World-transforms">World transforms</a> in the Spine
 	 * Runtimes Guide.
 	 * @param worldVertices The output world vertices. Must have a length >= <code>offset</code> + 8.
+	 * @param vertexOffsets The vertex {@link Sequence#getOffsets(int) offsets}.
 	 * @param offset The <code>worldVertices</code> index to begin writing values.
 	 * @param stride The number of <code>worldVertices</code> entries between the value pairs written. */
-	public void computeWorldVertices (Slot slot, float[] worldVertices, int offset, int stride) {
+	public void computeWorldVertices (Slot slot, float[] vertexOffsets, float[] worldVertices, int offset, int stride) {
-		if (sequence != null) sequence.apply(slot.getAppliedPose(), this);
-
-		float[] vertexOffset = this.offset;
 		BonePose bone = slot.getBone().getAppliedPose();
 		float x = bone.getWorldX(), y = bone.getWorldY();
 		float a = bone.getA(), b = bone.getB(), c = bone.getC(), d = bone.getD();
-		float offsetX, offsetY;
 
-		offsetX = vertexOffset[BRX];
+		float offsetX = vertexOffsets[BRX];
-		offsetY = vertexOffset[BRY];
+		float offsetY = vertexOffsets[BRY];
 		worldVertices[offset] = offsetX * a + offsetY * b + x; // br
 		worldVertices[offset + 1] = offsetX * c + offsetY * d + y;
 		offset += stride;
 
-		offsetX = vertexOffset[BLX];
+		offsetX = vertexOffsets[BLX];
-		offsetY = vertexOffset[BLY];
+		offsetY = vertexOffsets[BLY];
 		worldVertices[offset] = offsetX * a + offsetY * b + x; // bl
 		worldVertices[offset + 1] = offsetX * c + offsetY * d + y;
 		offset += stride;
 
-		offsetX = vertexOffset[ULX];
+		offsetX = vertexOffsets[ULX];
-		offsetY = vertexOffset[ULY];
+		offsetY = vertexOffsets[ULY];
 		worldVertices[offset] = offsetX * a + offsetY * b + x; // ul
 		worldVertices[offset + 1] = offsetX * c + offsetY * d + y;
 		offset += stride;
 
-		offsetX = vertexOffset[URX];
+		offsetX = vertexOffsets[URX];
-		offsetY = vertexOffset[URY];
+		offsetY = vertexOffsets[URY];
 		worldVertices[offset] = offsetX * a + offsetY * b + x; // ur
 		worldVertices[offset + 1] = offsetX * c + offsetY * d + y;
 	}
 
-	/** For each of the 4 vertices, a pair of <code>x,y</code> values that is the local position of the vertex.
+	/** Returns the vertex {@link Sequence#getOffsets(int) offsets} for the specified slot pose. */
-	 * <p>
+	public float[] getOffsets (SlotPose pose) {
-	 * See {@link #updateRegion()}. */
+		return sequence.getOffsets(sequence.resolveIndex(pose));
-	public float[] getOffset () {
-		return offset;
-	}
-
-	public float[] getUVs () {
-		return uvs;
 	}
 
 	/** The local x translation. */
@@ -279,8 +180,12 @@ public class RegionAttachment extends Attachment implements HasTextureRegion {
 		this.height = height;
 	}
 
-	public Color getColor () {
+	public Sequence getSequence () {
-		return color;
+		return sequence;
+	}
+
+	public void updateSequence () {
+		sequence.update(this);
 	}
 
 	public String getPath () {
@@ -291,15 +196,80 @@ public class RegionAttachment extends Attachment implements HasTextureRegion {
 		this.path = path;
 	}
 
-	public @Null Sequence getSequence () {
+	public Color getColor () {
-		return sequence;
+		return color;
-	}
-
-	public void setSequence (@Null Sequence sequence) {
-		this.sequence = sequence;
 	}
 
 	public RegionAttachment copy () {
 		return new RegionAttachment(this);
 	}
+
+	/** Computes {@link Sequence#getUVs(int) UVs} and {@link Sequence#getOffsets(int) offsets} for a region attachment.
+	 * @param uvs Output array for the computed UVs, length of 8.
+	 * @param offset Output array for the computed vertex offsets, length of 8. */
+	static void computeUVs (@Null TextureRegion region, float x, float y, float scaleX, float scaleY, float rotation, float width,
+		float height, float[] offset, float[] uvs) {
+		float localX2 = width / 2, localY2 = height / 2;
+		float localX = -localX2, localY = -localY2;
+		boolean rotated = false;
+		if (region instanceof AtlasRegion r) {
+			localX += r.offsetX / r.originalWidth * width;
+			localY += r.offsetY / r.originalHeight * height;
+			if (r.degrees == 90) {
+				rotated = true;
+				localX2 -= (r.originalWidth - r.offsetX - r.packedHeight) / r.originalWidth * width;
+				localY2 -= (r.originalHeight - r.offsetY - r.packedWidth) / r.originalHeight * height;
+			} else {
+				localX2 -= (r.originalWidth - r.offsetX - r.packedWidth) / r.originalWidth * width;
+				localY2 -= (r.originalHeight - r.offsetY - r.packedHeight) / r.originalHeight * height;
+			}
+		}
+		localX *= scaleX;
+		localY *= scaleY;
+		localX2 *= scaleX;
+		localY2 *= scaleY;
+		float r = rotation * degRad, cos = cos(r), sin = sin(r);
+		float localXCos = localX * cos + x;
+		float localXSin = localX * sin;
+		float localYCos = localY * cos + y;
+		float localYSin = localY * sin;
+		float localX2Cos = localX2 * cos + x;
+		float localX2Sin = localX2 * sin;
+		float localY2Cos = localY2 * cos + y;
+		float localY2Sin = localY2 * sin;
+		offset[BLX] = localXCos - localYSin;
+		offset[BLY] = localYCos + localXSin;
+		offset[ULX] = localXCos - localY2Sin;
+		offset[ULY] = localY2Cos + localXSin;
+		offset[URX] = localX2Cos - localY2Sin;
+		offset[URY] = localY2Cos + localX2Sin;
+		offset[BRX] = localX2Cos - localYSin;
+		offset[BRY] = localYCos + localX2Sin;
+		if (region == null) {
+			uvs[BLX] = 0;
+			uvs[BLY] = 0;
+			uvs[ULX] = 0;
+			uvs[ULY] = 1;
+			uvs[URX] = 1;
+			uvs[URY] = 1;
+			uvs[BRX] = 1;
+			uvs[BRY] = 0;
+		} else {
+			uvs[BLX] = region.getU2();
+			uvs[ULY] = region.getV2();
+			uvs[URX] = region.getU();
+			uvs[BRY] = region.getV();
+			if (rotated) {
+				uvs[BLY] = region.getV();
+				uvs[ULX] = region.getU2();
+				uvs[URY] = region.getV2();
+				uvs[BRX] = region.getU();
+			} else {
+				uvs[BLY] = region.getV2();
+				uvs[ULX] = region.getU();
+				uvs[URY] = region.getV();
+				uvs[BRX] = region.getU2();
+			}
+		}
+	}
 }

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/attachments/Sequence.java

@@ -35,46 +35,88 @@ import com.badlogic.gdx.graphics.g2d.TextureRegion;
 
 import com.esotericsoftware.spine.SlotPose;
 
+/** Holds texture regions, UVs, and vertex offsets for rendering a region or mesh attachment. {@link #getRegions() Regions} must
+ * be populated and {@link #update(HasSequence)} called before use. */
 public class Sequence {
 	static private int nextID;
 
 	private final int id = nextID();
 	private final TextureRegion[] regions;
+	private final boolean pathSuffix;
+	private float[][] uvs, offsets;
 	private int start, digits, setupIndex;
 
-	public Sequence (int count) {
+	public Sequence (int count, boolean pathSuffix) {
 		regions = new TextureRegion[count];
+		this.pathSuffix = pathSuffix;
 	}
 
 	/** Copy constructor. */
 	protected Sequence (Sequence other) {
-		regions = new TextureRegion[other.regions.length];
+		int regionCount = other.regions.length;
-		arraycopy(other.regions, 0, regions, 0, regions.length);
+		regions = new TextureRegion[regionCount];
+		arraycopy(other.regions, 0, regions, 0, regionCount);
 
 		start = other.start;
 		digits = other.digits;
 		setupIndex = other.setupIndex;
-	}
+		pathSuffix = other.pathSuffix;
 
-	public void apply (SlotPose slot, HasTextureRegion attachment) {
+		if (other.uvs != null) {
-		int index = slot.getSequenceIndex();
+			int length = other.uvs[0].length;
-		if (index == -1) index = setupIndex;
+			uvs = new float[regionCount][length];
-		if (index >= regions.length) index = regions.length - 1;
+			for (int i = 0; i < regionCount; i++)
-		TextureRegion region = regions[index];
+				arraycopy(other.uvs[i], 0, uvs[i], 0, length);
-		if (attachment.getRegion() != region) {
+		}
-			attachment.setRegion(region);
+		if (other.offsets != null) {
-			attachment.updateRegion();
+			offsets = new float[regionCount][8];
+			for (int i = 0; i < regionCount; i++)
+				arraycopy(other.offsets[i], 0, offsets[i], 0, 8);
 		}
 	}
 
-	public String getPath (String basePath, int index) {
+	/** Computes UVs and offsets for the specified attachment. Must be called if the regions or attachment properties are
-		var buffer = new StringBuilder(basePath.length() + digits);
+	 * changed. */
-		buffer.append(basePath);
+	public void update (HasSequence attachment) {
-		String frame = Integer.toString(start + index);
+		int regionCount = regions.length;
-		for (int i = digits - frame.length(); i > 0; i--)
+		if (attachment instanceof RegionAttachment region) {
-			buffer.append('0');
+			uvs = new float[regionCount][8];
-		buffer.append(frame);
+			offsets = new float[regionCount][8];
-		return buffer.toString();
+			for (int i = 0; i < regionCount; i++) {
+				RegionAttachment.computeUVs(regions[i], region.x, region.y, region.scaleX, region.scaleY, region.rotation,
+					region.width, region.height, offsets[i], uvs[i]);
+			}
+		} else if (attachment instanceof MeshAttachment mesh) {
+			float[] regionUVs = mesh.regionUVs;
+			uvs = new float[regionCount][regionUVs.length];
+			offsets = null;
+			for (int i = 0; i < regionCount; i++)
+				MeshAttachment.computeUVs(regions[i], regionUVs, uvs[i]);
+		}
+	}
+
+	public TextureRegion[] getRegions () {
+		return regions;
+	}
+
+	public int resolveIndex (SlotPose pose) {
+		int index = pose.getSequenceIndex();
+		if (index == -1) index = setupIndex;
+		if (index >= regions.length) index = regions.length - 1;
+		return index;
+	}
+
+	public TextureRegion getRegion (int index) {
+		return regions[index];
+	}
+
+	public float[] getUVs (int index) {
+		return uvs[index];
+	}
+
+	/** Returns vertex offsets from the center of a {@link RegionAttachment}. Invalid to call for a {@link MeshAttachment}. */
+	public float[] getOffsets (int index) {
+		return offsets[index];
 	}
 
 	public int getStart () {
@@ -102,8 +144,19 @@ public class Sequence {
 		this.setupIndex = index;
 	}
 
-	public TextureRegion[] getRegions () {
+	public boolean getPathSuffix () {
-		return regions;
+		return pathSuffix;
+	}
+
+	public String getPath (String basePath, int index) {
+		if (!pathSuffix) return basePath;
+		var buffer = new StringBuilder(basePath.length() + digits);
+		buffer.append(basePath);
+		String frame = Integer.toString(start + index);
+		for (int i = digits - frame.length(); i > 0; i--)
+			buffer.append('0');
+		buffer.append(frame);
+		return buffer.toString();
 	}
 
 	/** Returns a unique ID for this attachment. */