Some areas where I have used this utility are:

• The AI system can display a units’ velocity and position through Lines, Arrows, and Spheres. Use ScreenText to show the current state or goal hierarchy of a given unit.
• The Physics system can use bounding boxes and spheres to show collision volumes. Points can be used to show raycast intersections or points of impact.
• The Graphics system can use Spheres, Lines, and Arrows to show the position and direction of lights.
• The Editor (or other tools) can use Lines, Arrows, and Bounding Boxes for axis representation during translate/rotate/scale.
• Vertex Display – For a software-based skinning implementation, I used Points to visualize the locations of my vertices, and Spheres for the locations of the bones. It’s possible to use Spheres for everything, but thousands of Spheres can get a little expensive.

This utility is only meant for Debug purposes, and therefore uses the [Conditional("DEBUG")] tag on each of it’s exposed methods.

To use the DebugOverlay, create the object during Initialization:

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new DebugOverlay(GraphicsDevice, Content);

Call the visualization functions from anywhere in your code:

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void ScreenText(string text, Vector2 pos, Color c)
void Line(Vector3 start, Vector3 end, Color color)
void Arrow(Vector3 start, Vector3 end, float arrowSize, Color color)
void BoundingBox(BoundingBox boundingBox, Color color)
void Point(Vector3 pos, Color color)
void Sphere(Vector3 pos, float radius, Color color)

In your Draw routine, call the DebugOverlay.Draw method, passing in the projection and view matrices:

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DebugOverlay.Singleton.Draw(mCamera.ProjectionMatrix, mCamera.ViewMatrix);

I made a small sample application to show off the functionality. Below is a screenshot and the complete source code.

Download: source + demo

This created a situation where we were unable to prototype levels quickly, and time that could be better used somewhere else was being wasted.

Because of this, I devoted the first few weeks of the second semester to full-time tool development. Two of the more useful tools created are described below. These tools, once created, were continuously used and refined throughout the entire life of the project.

Level Editor:

Artemis Chronicle and the NitroX engine have a completely integrated level editor. The editor allows 3D navigation through the world (using Maya camera controls), object placement (translation, rotation, scale), object property exposure (including physics volumes), trigger volumes (used for scripted events), and interactive camera sequencing (allows us to create cut-scenes and cinematics in a point-and-click fashion instead of in code).

The editor runs on Windows and is written in C#, allowing for close integration into the XNA content pipeline. The editor data is serialized out to an XML format (which is later compressed for application deployment), sent through the content pipeline, and imported directly into the NitroX engine for use on both Windows and Xbox 360.

Mesh Viewer:

The Mesh Viewer is a tool that lets our artists quickly preview their work before sending it off to be integrated into the latest build of the game. As anyone who’s used the FBX exporter knows, exporting from Maya does not always go smoothly, so this tool allows the artist to catch any errors early, thus saving time for the entire team.

Animations can be chained together to create sequences, and then previewed in a real-time manner. Playback speed, blending parameters, and looping can also be adjusted via the user interface.