Spontz Visuals Editor is the Spontz demogroup's demotool. It's available for Windows and MacOS.
Link:
http://en.spontz.org/index.php?pageID=33Although it's impossible to consider the Spontz demo editor stable, it deserves the 2.0 version change. The rework includes support to open multiple projects at the same time with copy and paste support between them. The demo engine now communicates through TCP/IP with the demo editor, making possible a realtime preview. Other features include GLSL shaders support, Frame Buffer Objects support (FBOs) and a realtime expression evaluator, that allows to vary almost all the parametrs along the time.