Fix issue with corrupted texture cache

If the texture cache doesn't return images in exactly the order or way
that libHSPlasma is expecting, it raises a RuntimeError. We can detect
that we used a cached image and regenerate the data in that case...
instead of just outright failing with "image data size mismatch".

korman/exporter/material.py

@@ -781,16 +781,27 @@ class MaterialConverter:
                 cached_image = texcache.get_from_texture(key, compression)
 
                 if cached_image is None:
-                    if key.is_cube_map:
-                        numLevels, width, height, data = self._finalize_cube_map(key, image, name, compression, dxt)
-                    else:
-                        numLevels, width, height, data = self._finalize_single_image(key, image, name, compression, dxt)
-                    texcache.add_texture(key, numLevels, (width, height), compression, data)
+                    numLevels, width, height, data = self._finalize_cache(texcache, key, image, name, compression, dxt)
+                    self._finalize_bitmap(key, owners, name, numLevels, width, height, compression, dxt, data)
                 else:
                     width, height = cached_image.export_size
                     data = cached_image.image_data
                     numLevels = cached_image.mip_levels
 
+                    # If the cached image data is junk, PyHSPlasma will raise a RuntimeError,
+                    # so we'll attempt a recache...
+                    try:
+                        self._finalize_bitmap(key, owners, name, numLevels, width, height, compression, dxt, data)
+                    except RuntimeError:
+                        self._report.warn("Cached image is corrupted! Recaching image...", indent=1)
+                        numLevels, width, height, data = self._finalize_cache(texcache, key, image, name, compression, dxt)
+                        self._finalize_bitmap(key, owners, name, numLevels, width, height, compression, dxt, data)
+
+                inc_progress()
+
+    def _finalize_bitmap(self, key, owners, name, numLevels, width, height, compression, dxt, data):
+        mgr = self._mgr
+
         # Now we poke our new bitmap into the pending layers. Note that we have to do some funny
         # business to account for per-page textures
         pages = {}
@@ -833,9 +844,15 @@ class MaterialConverter:
             elif isinstance(owner, plImageLibMod):
                 owner.addImage(texture.key)
             else:
-                        raise RuntimeError(owner.ClassName())
+                raise NotImplementedError(owner.ClassName())
 
-                inc_progress()
+    def _finalize_cache(self, texcache, key, image, name, compression, dxt):
+        if key.is_cube_map:
+            numLevels, width, height, data = self._finalize_cube_map(key, image, name, compression, dxt)
+        else:
+            numLevels, width, height, data = self._finalize_single_image(key, image, name, compression, dxt)
+        texcache.add_texture(key, numLevels, (width, height), compression, data)
+        return numLevels, width, height, data
 
     def _finalize_cube_map(self, key, image, name, compression, dxt):
         oWidth, oHeight = image.size