Tips for Developing Custom Importers and Processors

The information provided should help when you develop Content Pipeline extensions.

Importing Basic Graphics Objects

The following information should help you import basic graphics objects.

• Make your coordinate system right-handed.

  From the standpoint of the observer, the positive x-axis points to the right, the positive y-axis points up, and the positive z-axis points toward you (out from the screen).

• Create triangles that have a clockwise winding order.

  The default culling mode removes triangles that have a counterclockwise winding order.

• Call SwapWindingOrder to change the winding order of a triangle.

• Set the scale for graphical objects to 1 unit = 1 meter.

• Call TransformScene to change the scale of an object.

Taking Advantage of Content Pipeline Mesh Classes

There are several properties and classes that are particularly useful when using NodeContent objects to represent a 3D scene or mesh.

• The NodeContent.Children property represents hierarchical information.

• The NodeContent.Transform property contains the local transform of the 3D object.

• The Pipeline.Graphics.MeshContent class (a subclass of Pipeline.Graphics.NodeContent) is used to represent meshes.

The Content Pipeline provides two classes that make it easier to create and work with Pipeline.Graphics.MeshContent objects.

• The Pipeline.Graphics.MeshBuilder class creates new Pipeline.Graphics.MeshContent objects, when necessary.

• The Pipeline.Graphics.MeshHelper class implements useful operations on existing Pipeline.Graphics.MeshContent objects.

Debugging Custom Importers and Processors

In a manner similar to projects that create a DLL, Content Pipeline extension projects cannot be directly run or debugged. After completing a few simple steps, however, you can debug any custom importer and processor used by your game. The following procedure details these steps.

Note

The Start External program control (located on the Debug page of a project's property pages) is unavailable in the Microsoft Visual C# Express Edition development environment.

To debug a custom importer or processor

1. Load an existing XNA Game Studio Content Pipeline extension project (later referred to as ProjCP) containing the custom importers or processors to be debugged.

2. Create a separate test game project (later referred to as "ProjG").

3. In the References node of ProjG's nested content project, add a project-to-project reference to ProjCP.

4. Add one or two appropriate items of test content to ProjG, and ensure they are set to use the importer or processor (in ProjCP) you wish to debug.

5. Open the property pages for ProjCP.

6. Click the Debug tab, and then select Start external program.

7. Enter the path to the local version of MSBuild.exe.

   For example, C:\WINDOWS\Microsoft.NET\Framework\v3.5\msbuild.exe.

8. For the Command line arguments control, enter the path to ProjG's nested content project.

   If this path contains spaces, quote the entire path.

9. Set any required breakpoints in the importer or processor code in ProjCP.

10. Build and debug ProjCP.

Debugging ProjCP causes MSBuild to compile your test content while running under the debugger. This enables you to hit your breakpoints in ProjCP and to step through your code.

See Also

What Is Content?
What is the Content Pipeline?
Creating a Custom Importer and Processor
Extending a Standard Content Processor
Adding New Content Types