SuperDirt.start: s.options settings are ignored if server is already booted (causes crash if default memory is too low for global effects)

[elgiano]

SuperDirt.start (the class method) sets some server options before calling waitForBoot. But if the server is already running, these options are ignored until it's rebooted (that's how scsynth works). So:

s.waitForBoot { SuperDirt.start }

Can start scsynth with too little memory for global effects, causing a server crash. The crash by the way is ugly: it just says "server disconnected shared memory interface..." and so on, without mentioning any "memory allocation fail". This is because sc3-plugins don't fail gracefully yet in this cases.

All of the startup examples call s.reboot and I think SuperDirt.start should do it as well:

diff --git a/classes/extSuperDirtStartup.sc b/classes/extSuperDirtStartup.sc
index ece2d75..f7014a3 100644
--- a/classes/extSuperDirtStartup.sc
+++ b/classes/extSuperDirtStartup.sc
@@ -8,6 +8,7 @@
 	*start { |numChannels = 2, server, numOrbits = 12, port = 57120, senderAddr, path|
 		~dirt.free;
 		server = server ? Server.default;
+		server.reboot{
 		server.options.numBuffers = 1024 * 256;
 		server.options.memSize = 8192 * 16;
 		server.options.maxNodes = 1024 * 32;
@@ -18,6 +19,7 @@
 			server.sync;
 			~dirt.start(port, 0 ! numOrbits, senderAddr);
 		};
+		}
 
 		server.latency = 0.3;
 	}

I encountered this while working on other SuperCollider issues (supercollider/supercollider#6992).
SC 3.14 has a new command for checking free realtime memory, so we were discussing with @telephon if SuperDirt should check how much free memory is available before starting.

I measured on my system, that SuperDirt needs at least 34MB of realtime memory (supercollider's default is 8), but this can vary depening on setup/sampleRate. If SuperDirt wanted to ensure there are at least 50MB of free memory before starting, it could do it like so:

s.rtMemoryStatus { |freeBytes|
    // note that this function runs async after a server reply
    var freeKilobytes = freeBytes / 1024;
    if (freeKilobytes < (50 * 1024)) {
        Error("SuperDirt: not enough free memory to start. Set s.options.memSize to at least 50 * 1024").throw
     }
}