OpenGL Questions

How do I record OpenGL scenes to disk as a QuickTime movie using jit.qt.record?

You need to generate a 2D raster of the OpenGL data. Jitter offers a few ways to do this, and one of them will probably work for your application.

• Instead of rendering to a jit.window object, you can render to a jit.matrix object (it must be a 4 plane char matrix, named identically to the jit.gl.render object you're using). You can then record the output of the jit.matrix object using jit.qt.record. At this time, rendering to jit.matrix is done in software, so it's quite a bit slower than rendering to a jit.window.
• Render to a jit.window, and use jit.desktop to capture the portion of the screen occupied by the window. You can then record the output of jit.desktop using jit.qt.record.
• Use jit.gl.sketch's 'glreadpixels' message to write the data into a jit.matrix, and record the output using jit.qt.record.

All three of these methods are demonstrated in this patch

How do I create a text or image overlay in an OpenGL scene?

The most effective way to accomplish this is to use what's commonly referred to as the Painter's Algorithm. What this means is that you will draw each object in the scene in order of depth, much like a painter might paint the background of a scene before painting the foreground on top of it. For a simple example of how this might work, see Jitter Recipe 28
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