Merge pull request #10 from RobertBendun/feature/simple-api

Simple Lua API example using shared memory

CHANGELOG.md

@@ -7,6 +7,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- New shared memory API
+- Example of shared memory API usage in Lua using C library
+
+### Changed
+
+- Renamed "MIDI Sources" to "Blocks" to account for new forms of musical actions
+
 ## [0.1.2] - 2024-04-26
 
 ### Added

Cargo.toml

@@ -59,6 +59,7 @@ futures = "0.3.30"
 rust-embed = "8.3.0"
 mime_guess = "2.0.4"
 tracing-appender = "0.2.3"
+shared_memory = "0.12.4"
 
 [dependencies.rusty_link]
 git = "https://github.com/RobertBendun/rusty_link.git"

examples/lua-shared-memory/.gitignore

@@ -0,0 +1,2 @@
+harmonia.so
+clock

examples/lua-shared-memory/Makefile

@@ -0,0 +1,6 @@
+all: harmonia.so clock
+
+harmonia.so: harmonia.c
+	gcc $< -shared -o $@ -fPIC  -llua -lrtmidi -Wall -Wextra
+
+LDLIBS=-lm -lrt

examples/lua-shared-memory/README.md

@@ -0,0 +1,13 @@
+# Example: simple Lua integration using unix sockets
+
+This example creates a simple musical embeded language inside Lua, using coroutines.
+It provides mechanism that is similar in UX to the very simplified SonicPI.
+
+Tested only on Linux. Requires [RtMidi](https://github.com/thestk/rtmidi), [Lua 5.4](https://www.lua.org/) and C compiler.
+
+## Usage
+
+```console
+$ make
+$ lua5.4 demo.lua
+```

examples/lua-shared-memory/clock.c

@@ -0,0 +1,46 @@
+#include <time.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <math.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <signal.h>
+#include <fcntl.h>
+
+static int fd;
+char const* path = "/harmonia-block";
+
+void clean(int)
+{
+	shm_unlink(path);
+	exit(1);
+}
+
+int main()
+{
+	signal(SIGINT, clean);
+
+	if ((fd = shm_open(path, O_RDWR|O_CREAT, 0600)) < 0) {
+		perror("shm_open");
+		return 1;
+	}
+
+	ftruncate(fd, sizeof(double));
+
+	double* p = mmap(NULL, sizeof(double), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+
+	for (;;) {
+		struct timespec ts;
+		clock_gettime(CLOCK_MONOTONIC, &ts);
+		*p = (double)ts.tv_sec + ts.tv_nsec/1000000000.0;
+
+		float f = 0.005;
+		nanosleep(&(struct timespec) {
+				.tv_sec = floor(f),
+				.tv_nsec = (f - floor(f)) * 1000000000,
+		}, NULL);
+	}
+}

examples/lua-shared-memory/demo.lua

@@ -0,0 +1,33 @@
+harmonia = require "harmonia"
+
+-- https://computermusicresource.com/midikeys.html
+c2 = 48
+e2 = 52
+g2 = 55
+c4 = 72
+e4 = 76
+g4 = 79
+
+function play(note, duration)
+	coroutine.yield("play", note, duration)
+end
+
+function sleep(duration)
+	coroutine.yield("sleep", duration)
+end
+
+harmonia.bind_block("/harmonia-test", function ()
+	local prog = {c4, e4, g4}
+
+	for i = 1,8 do
+		for j = 1,i do
+			local time = 2 ^ (1 - i)
+			play(prog[i//#prog + 1], time)
+			sleep(time)
+		end
+	end
+
+	play(c2, 1)
+	play(e2, 1)
+	play(g2, 1)
+end)