This is awesome and really shows off the beautiful compactness of Forth.
It took me a moment to figure out what to actually do. Basically you just write a little program that produces three floating-point values from 0.0 to 1.0, and these are used as the R, G, and B channels of each pixel in the output. For example, an all-red image is:
1 0 0
And a blue-cyan-magenta rectangle is:
x y 1
You get the x and y of the current pixel with the “x” and “y” words, and you get the current time with the “t” word in order to make animations. Here’s one that continually oscillates between black and white:
: r 5 ;
: sin' sin 1 + 2 / ;
: t' t r * sin' ;
t' t' t'
(You can change the value of “r” to make it oscillate faster or slower.)
Looking at the glossary[1] and cannibalising other examples is really helpful.
Cool. Unfortunately I saw all these things on the “about” page after I had figured out how to use it through trial and error. That’s what I get for not paying attention!
http://shadertoy.com/ uses GLSL (or whatever its WebGL equivalent is). Is that what you're thinking of?
(The language is syntactically similar to C, but quite different from it in some respects, as it compiles to code that runs directly on the GPU. GPUs have a very different execution model from a CPU - though they have been moving closer together and I guess that trend will continue. On the plus side, the performance can be excellent, provided your PC has a decent GPU.)
It took me a moment to figure out what to actually do. Basically you just write a little program that produces three floating-point values from 0.0 to 1.0, and these are used as the R, G, and B channels of each pixel in the output. For example, an all-red image is:
And a blue-cyan-magenta rectangle is: You get the x and y of the current pixel with the “x” and “y” words, and you get the current time with the “t” word in order to make animations. Here’s one that continually oscillates between black and white: (You can change the value of “r” to make it oscillate faster or slower.)Looking at the glossary[1] and cannibalising other examples is really helpful.
[1]: http://forthsalon.appspot.com/word-list