"ShaderForth", closely following the implementation of Forth Haiku Salon, implemented in C. A Forth-like language is executed once for each pixel in an output image. The image is output on the standard output in plain PPM format.

make examples will generate a few GIF animations in the examples directory.

• Simple Forth-like compiler based on the Forth Haiku Salon language
• Plain PPM output
• Script to generate animated GIF pictures (multicore!): sfgif
• All non-primitive words are inlined

• C compiler (I've used GCC but any C99 compiler should work
• bash, xargs, dc, ImageMagick (convert) for sfgif

• dt: this implementation has no concept of time, though dt can be implemented as part of sfgif
• mx, my, button, buttons: this implementation has no input handling
• audio: this implementation has no audio output
• sample, bwsample: this implementation has no image sampling
• \: this implementation has no line comments (yet)
• @, !: this implementation provides no memory access (yet)
• if, else, then: this implementation is (for now) completely branchless
• No alpha channel
• Word names and numbers are limited to 31 characters each. Names and numbers longer than this may be used, but will be truncated

• width, height: Set the output image height/width. The program is executed once with its other output discarded just to retreive these values if set. If they are not set, the default of 256x256 is used.

A brief description of the modules:

• codebuf: A growable buffer that holds instructions
• compiler: Sets up a tokenizer and handles the tokens one by one, compiling them to the virtual machine
• instruction: The instruction type and the code that runs when it is executed
• machine: contains two codebufs, two stacks and a small scratch memory. One data stack and one "return stack" (which isn't actually a return stack in Forth Haiku Salon and can be used across word boundaries); one main codebuf and one macro codebuf that holds compiled words
• readfile: function to read a file by filename, allocating space for it and returning the data, leaving it for the caller to free
• stack: Simple fixed size stack which can be used for push/pop operations
• std: Standard library of primitive words
• tokenizer: Simple tokenizer, the only real concern is to output words separated by whitespace one by one
• types: Some of the types are interdependent, so most types relating to the virtual machine are stored here
• wordlink: a simple linked list dictionary. This is used by the compiler to look up word names
• sf: Main program, sets up the virtual machine, handles arguments etc.

• Compilation, runtime error output with line numbers
• Implement \ line comments
• Implement @ and ! as in ForthSalon
• (Maybe) implement IF ... ELSE ... THEN, though I like keeping it branchless
• (Maybe) implement random