Bytebeat and floatbeat machine.
Bytebeat is a type of music made from mathematical formulas, first discovered by Viznut in 2011.
The idea is that t represents a timer, infinitely increasing. In most cases t increases 8000 times per second (for a 8000Hz bytebeat song), but you can also let t represent a 44100Hz timer if you like.
If you take the next formula with a 8000Hz timer
t | (t >> 4)
then a bytebeat generator will compute the above formula 8000 times per second for the corresponding value of t. Next the result (which can be a large value) is brought back to 8 bit by only retaining the remainder of the integer division by 256. This 8-bit value is sent to the speakers. The above formula sounds like this.
Floatbeat is very similar to bytebeat. The difference is that the formula can use floating point (decimal) computations, and the result is expected to be in the interval [-1, 1]. Again this value is reworked to a 8-bit value and sent to the speakers. The advantage of floatbeat is that it is more natural here to work with sine and cosine functions. The next formula with a 44100Hz timer
sin(440*t*3.1415926535*2/44100)
generates a 440Hz tone, like this.
There are already a bunch of very nice bytebeat and floatbeat generators available, such as
- Greggman's html5bytebeat
- Viznut's IBNIZ
- Wurstcaptures
- Rampcode
- probably many others
Forthbyte is my attempt at generating a bytebeat and floatbeat machine using a dialect of the language Forth. If you want to try it out, you can take a look at some examples in the examples subfolder.
First of all, forthbyte uses submodules, so don't forget to also call
git submodule update --init
Next, run CMake to generate a solution file on Windows, a make file on Linux, or an XCode project on MacOs. You can build forthbyte without building other external projects (as all necessary dependencies are delivered with the code).
^A : Select all
^B : Build the current buffer. If you are playing, the new compiled song will continue playing.
^C : Copy to the clipboard (pbcopy on MacOs, xclip on Linux)
^E : Whenever you play, the song is recorded on disk to a wav file. With this command you can set the output file. If not set by ^E, the default output file is session.wav in your forthbyte binaries folder.
^N : Make an empty buffer
^P : Play / pause
^H : Show tis help text
^K : Stop playing
^O : Open a file
^R : Restart the timer t
^S : Save the current file
^W : Save the current file as
^V : Paste from the clipboard (pbpaste on MacOs, xclip on Linux)
^X : Exit this application, or cancel the current operation
^Y : Redo
^Z : Undo
#byte use bytebeat
#float use floatbeat (this is the default)
#samplerate nr set the sample rate (default value is 8000)
#initmemory a b c ... initializes the memory with the values given by a, b, c, ... . There are 256 memory spots available.
t the timer
sr the current samplerate that was set by the preprocessor directive #samplerate
c the current channel. It's possible to use stereo. The left channel has a value of c equal to 0, and the right channel has a value equal to 1.
The Forth stack has 256 entries. If you go over this amount, the counter resets to zero, so you never can get a stack overflow. Similar for the memory entries, or the Forth return stack.
+ ( a b -- c ) Pops the two top values from the stack, and pushes their sum on the stack.
- ( a b -- c ) Pops the two top values from the stack, and pushes their subtraction on the stack.
* ( a b -- c ) Pops the two top values from the stack, and pushes their multiplication on the stack.
/ ( a b -- c ) Pops the two top values from the stack, and pushes their division on the stack.
<< ( a b -- c ) Pops the two top values from the stack, and pushes their left shift on the stack.
>> ( a b -- c ) Pops the two top values from the stack, and pushes their right shift on the stack.
& ( a b -- c ) Pops the two top values from the stack, and pushes their binary and on the stack.
| ( a b -- c ) Pops the two top values from the stack, and pushes their binary or on the stack.
^ ( a b -- c ) Pops the two top values from the stack, and pushes their binary xor on the stack.
% ( a b -- c ) Pops the two top values from the stack, and pushes their modulo on the stack.
< ( a b -- c ) Pops the two top values from the stack, compares them with <, and puts 0 on the stack if the comparison fails, 1 otherwise.
> ( a b -- c ) Pops the two top values from the stack, compares them with >, and puts 0 on the stack if the comparison fails, 1 otherwise.
<= ( a b -- c ) Pops the two top values from the stack, compares them with <=, and puts 0 on the stack if the comparison fails, 1 otherwise.
>= ( a b -- c ) Pops the two top values from the stack, compares them with >=, and puts 0 on the stack if the comparison fails, 1 otherwise.
= ( a b -- c ) Pops the two top values from the stack, compares them with =, and puts 0 on the stack if the comparison fails, 1 otherwise.
<> ( a b -- c ) Pops the two top values from the stack, compares them with <> (not equal), and puts 0 on the stack if the comparison fails, 1 otherwise.
@ ( a -- b ) Pops the top value from the stack, gets the value at memory address a, and pushes this value on the stack.
! ( a b -- ) Pops the two top values from the stack, and stores value a at memory address b.
>r ( a -- ) Pops the top value from the stack, and moves it to the return stack. The return stack has 256 entries.
r> ( -- a ) Pops the top value from the return stack, and moves it to the regular stack.
: ; Define a new word, e..g. : twice 2 * ; defines the word twice, so that 3 twice equals 3 2 * equals 6.
abs ( a -- b ) Pops the top value from the stack, and pushes the absolue value on the stack.
atan2 ( a b -- c ) Pops the two top values from the stack, and pushes atan2(a, b) on the stack.
ceil ( a -- b ) Pops the top value from the stack, rounds the value up, and pushes this value on the stack.
cos ( a -- b ) Pops the top value from the stack, and pushes the cosine on the stack.
drop ( a -- ) Pop the top element of the stack.
dup ( a -- a a ) Duplicate the value on the top of the stack.
2dup ( a b -- a b a b ) Duplicate the top two elements on the stack.
exp ( a -- b ) Pops the top value from the stack, and pushes the exponential on the stack.
floor ( a -- b ) Pops the top value from the stack, rounds the value down, and pushes this value on the stack.
log ( a -- b ) Pops the top value from the stack, and pushes the logarithm on the stack.
max ( a b -- c ) Pops the two top values from the stack, and pushes their maximum on the stack.
min ( a b -- c ) Pops the two top values from the stack, and pushes their minimum on the stack.
negate ( a -- b ) Pops the top value from the stack, and pushes the negative value on the stack.
nip ( a b -- b ) Drop the first item below the top of the stack.
not ( a -- b ) Pops the top value from the stack, and pushes the binary not on the stack.
over ( a b -- a b a ) Duplicate the element under the top stack element.
pick ( a_b ... a_1 a_0 b -- a_b ... a_1 a_0 a_b ) Remove b from the stack and copy a_b to the top of the stack.
pow ( a b -- c ) Pops the two top values from the stack, and pushes a to the power b on the stack.
rot ( a b c -- b c a ) Rotate the three top elements on the stack.
-rot ( a b c -- c a b ) Reverse rotate the three top elements on the stack.
sin ( a -- b ) Pops the top value from the stack, and pushes the sine on the stack.
sqrt ( a -- b ) Pops the top value from the stack, and pushes the square root on the stack.
swap ( a b -- b a ) Swaps the two top positions on the stack.
tan ( a -- b ) Pops the top value from the stack, and pushes the tangent on the stack.
tuck ( a b -- b a b ) Copy the top stack item below the second stack item.