[ts] Port of d6adbe9.

See https://github.com/EsotericSoftware/spine-runtimes/commit/d6adbe96d8af8ad19aaf9203434fb0e78d35e88a

spine-ts/spine-core/src/attachments/RegionAttachment.ts

@@ -88,6 +88,20 @@ export class RegionAttachment extends Attachment implements HasTextureRegion {
 	updateRegion (): void {
 		if (!this.region) throw new Error("Region not set.");
 		let region = this.region;
+		let uvs = this.uvs;
+
+		if (region == null) {
+			uvs[0] = 0;
+			uvs[1] = 0;
+			uvs[2] = 1;
+			uvs[3] = 1;
+			uvs[4] = 1;
+			uvs[5] = 1;
+			uvs[6] = 1;
+			uvs[7] = 0;
+			return;
+		}
+
 		let regionScaleX = this.width / this.region.originalWidth * this.scaleX;
 		let regionScaleY = this.height / this.region.originalHeight * this.scaleY;
 		let localX = -this.width / 2 * this.scaleX + this.region.offsetX * regionScaleX;
@@ -116,25 +130,24 @@ export class RegionAttachment extends Attachment implements HasTextureRegion {
 		offset[6] = localX2Cos - localYSin;
 		offset[7] = localYCos + localX2Sin;
 
-		let uvs = this.uvs;
 		if (region.degrees == 90) {
-			uvs[2] = region.u;
+			uvs[0] = region.u2;
+			uvs[1] = region.v;
+			uvs[2] = region.u2;
 			uvs[3] = region.v2;
 			uvs[4] = region.u;
-			uvs[5] = region.v;
-			uvs[6] = region.u2;
+			uvs[5] = region.v2;
+			uvs[6] = region.u;
 			uvs[7] = region.v;
-			uvs[0] = region.u2;
-			uvs[1] = region.v2;
 		} else {
-			uvs[0] = region.u;
+			uvs[0] = region.u2;
 			uvs[1] = region.v2;
 			uvs[2] = region.u;
-			uvs[3] = region.v;
-			uvs[4] = region.u2;
+			uvs[3] = region.v2;
+			uvs[4] = region.u;
 			uvs[5] = region.v;
 			uvs[6] = region.u2;
-			uvs[7] = region.v2;
+			uvs[7] = region.v;
 		}
 	}