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The perspective projection

To represent a 3D space on a 2D plane, XLogo uses a projection perspective. A camera looks at the 3D scene, where the image from the projection screen is displaying. Here is a little scheme to explain this:
\includegraphics[scale=0.6, clip]{images/perspective.eps}
Some primitives allow us to set the camera position. The screen projection is half the distance from the camera.

Loïc 2008-06-08