What to extend in the content pipeline

Originally posted to Shawn Hargreaves Blog on MSDN, Thursday, December 7, 2006

A cheat sheet listing some common content pipeline extensibility patterns

"I want to tweak my content in some way"

• Change the format or size of my textures
• Apply a custom effect to my models
• Convert a texture into a heightfield mesh

Solution: implement a custom ContentProcessor, either from scratch or by deriving from one of the built-in ones.

"I want to attach custom data to my content"

• Store a collision skin along with my model
• Store animation data along with my model

Solution: implement a custom ContentProcessor, deriving from one of the built-in ones. Override the Process method, and after you chain to the base class implementation, store your custom information in the Tag property of the output object.

If your custom data is not already a supported pipeline type, you will also need to implement a ContentTypeWriter and ContentTypeReader for it. I'll blog more about that sometime soon.

"I want to add a new content pipeline output type"

• The built-in Model class doesn't support everything I need, so I want to implement my own replacement.

Solution: implement a custom ContentProcessor, ContentTypeWriter, and ContentTypeReader.

"I want to support a new input file format"

• For some crazy reason I'm using Deluxe Paint on the Amiga to draw my textures, so I want to be able to import them from Amiga .lbm files.

Solution: implement a custom ContentImporter.

"I want to read game data from XML files"

• Mission descriptions
• AI or physics settings
• Configuration data for a particle system

Solution: wrap your XML data in <XnaContent> and <Asset> tags. Add the XML file to C# Express, go to the properties for this file and set "XNA Framework Content" to true, then choose the "XML Content Importer" and "No Processing Required". Finally, implement a ContentTypeWriter and ContentTypeReader for your custom type.

"I want to use fractals to compute the ultimate meaning of life"

Yeah, me too...