Bill, Thank you very much.
Mostly I want to get n turtles, not cubes, that are not rotating to time but behave like "Logo" turtles and react to commands in the Terminal window like Forward 3 and Right 90. So I want to start with 2 separate turtles and I guess I am all wrong in my idea that the long mvp commands are moving the eye, but moving the cube/turtle. So my next experiment will be to copy and edit the code beginning at the following line of code. glGenBuffers 2;vbo=: 2#_1 So for example to make another cube/turtle I'm thinking that that line could be changed so that _2 replaces the _1. Does that make any sense? *****************below I react to your code revisions*********************** I had to change your f8 and f9 to f6 and f7 because on my Mac f8 is clipboard and f9 is run project. Now, at least when I put an smoutput into a_f6_fkey and a_f7_fkey I see they are being executed, but I do not see the cube, (and this happens without changing the focus to the Terminal window, which is needed below). After intially loading and running the shader.ijs script in the project window, I get a blank "a" window and each time I press F10 I get a new fresh, blank "a" window. But if I click on the Terminal window and then click on the "a" window and THEN press F10, I get the moving cube. Subsequent F6 and F7 presses produce the smoutput results in the Terminal window but BLANK the active "a" window. *****************above I react to your code revisions*********************** But the previous paragraph is mostly a distraction except that you code revision shows me a little about how the "handle" is important for finding the parent from the child and vice versa. And about repainting. I am mostly interested in how commands in the Terminal window can be sent to the Cube in the "a" window. Any pointers? On Fri, Feb 14, 2020 at 1:58 AM bill lam <bbill....@gmail.com> wrote: > I tried to incoporate your change into shader.ijs > with f8/f9 to change value for gl_translate. > The changes lines are marked by NB. <<<<< > pressing f8/f9 can trigger repaint and the matrix > display also updated, but I can't see the cube at all. > Pressing F10 to start original code, the cube came back. > I did not pursue further but hope this is enough to > answer your question about how to repaint. > > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm