Load default texture into UV editor and auto-scale to fit canvas

src/components/UVEditor.tsx

@@ -47,7 +47,7 @@ export function UVEditor({ onClose, onSave, targetObject, loadedModel, sceneObje
 
   useEffect(() => {
     const saved = targetObject?.materialProps?.uvLayers;
-    if (!saved?.length) return;
+    if (saved?.length) {
       let n = 0;
       const init: Layer[] = saved.map((l: any) => ({ ...l }));
       init.forEach(layer => {
@@ -55,7 +55,36 @@ export function UVEditor({ onClose, onSave, targetObject, loadedModel, sceneObje
         img.onload = () => { layer.img = img; n++; if (n === init.length) setLayers([...init]); };
         img.src = layer.url;
       });
-  }, []);
+    } else if (targetObject?.materialProps?.map) {
+      // If no saved layers but there's a base map texture, load it as the initial layer
+      const url = targetObject.materialProps.map;
+      const img = new Image();
+      img.onload = () => {
+        // Automatically scale the image so it fits the 1024x1024 canvas exactly
+        const scaleX = CANVAS_SIZE / img.width;
+        const scaleY = CANVAS_SIZE / img.height;
+
+        const layer: Layer = {
+          id: `l-base`,
+          url,
+          img,
+          x: CANVAS_SIZE / 2,
+          y: CANVAS_SIZE / 2,
+          scaleX,
+          scaleY,
+          rotation: 0,
+          cropL: 0,
+          cropT: 0,
+          cropR: 0,
+          cropB: 0,
+          visible: true
+        };
+        setLayers([layer]);
+        setSelectedId(layer.id);
+      };
+      img.src = url;
+    }
+  }, [targetObject]);
 
   const renderCanvas = useCallback((lrs: Layer[], transparent: boolean, bg: string): string => {
     const c = document.createElement('canvas');