Fixed: Don't assume a sprite is in Patch format

At sprite definition time validate whether the associated resource
is a Patch and if so, obtain the world dimension and offset values
to attribute with the sprite. Otherwise, ignore the resource for
now and allow the texture loader to attribute the world dimensions
from the pixel dimensions of image resource at load time.

doomsday/engine/src/resource/r_data.cpp

@@ -742,8 +742,7 @@ void R_DefineSpriteTexture(TextureManifest &manifest)
     de::Texture *tex = manifest.derive();
     if(!tex)
     {
-        LOG_WARNING("Failed to define Texture for sprite \"%s\", ignoring.")
-            << manifest.composeUri();
+        LOG_WARNING("Failed to define Texture for sprite \"%s\", ignoring.") << manifest.composeUri();
         return;
     }
 
@@ -755,16 +754,34 @@ void R_DefineSpriteTexture(TextureManifest &manifest)
         lumpnum_t lumpNum = resourceUri.path().toString().toInt();
         de::File1& file = App_FileSystem()->nameIndex().lump(lumpNum);
 
-        /// @todo fixme: Ensure this is in Patch format.
+        // If this is from an add-on flag it as "custom".
+        if(file.container().hasCustom())
+        {
+            tex->flags() |= de::Texture::Custom;
+        }
+
+        // If this is a Patch read the world dimension and origin offset values.
         ByteRefArray fileData = ByteRefArray(file.cache(), file.size());
-        de::Reader from = de::Reader(fileData);
-        Patch::Header patchHdr;
-        from >> patchHdr;
+        if(Patch::recognize(fileData))
+        {
+            try
+            {
+                de::Reader from = de::Reader(fileData);
+                Patch::Header hdr;
+                from >> hdr;
 
-        tex->setOrigin(QPoint(-patchHdr.origin.x(), -patchHdr.origin.y()));
-        tex->setDimensions(patchHdr.dimensions);
-        if(file.hasCustom())
-            tex->flags() |= de::Texture::Custom;
+                tex->setDimensions(hdr.dimensions);
+                tex->setOrigin(QPoint(-hdr.origin.x(), -hdr.origin.y()));
+            }
+            catch(IByteArray::OffsetError const &)
+            {
+                LOG_WARNING("File \"%s:%s\" does not appear to be a valid Patch.\n"
+                            "World dimension and origin offset not set for sprite \"%s\".")
+                    << NativePath(file.container().composePath()).pretty()
+                    << NativePath(file.composePath()).pretty()
+                    << manifest.composeUri();
+            }
+        }
 
         file.unlock();
     }