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chuck 1.2.1.3 weird debug messages and aggregate devices
by mike clemow 06 Dec '09

06 Dec '09

Hi, chuck version: 1.2.1.3 (dracula) exe target: mac os x : intel I'm having trouble getting Chuck to not segfault using aggregate devices (only when trying to use more channels than in the first device) in Mac OS X 10.6. Has this always been an issue? Working around this for now, however, I'm curious what others' experiences have been with aggregate devices. Also, what's with the malloc messages in my newly compiled-from-source 1.2.1.3? Again, curious... Best, Mike -- http://michaelclemow.com http://semiotech.org

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Local-static bug
by Hans Aberg 05 Dec '09

05 Dec '09

For some reason, 'chuck' does not admit different type argument overloading on local & static class functions. The example below works as long as one does not call the static function. So either it should complain that it is illegal when encountering it in the class or admit this kind of overloading. Originally, I used a function "add" on intervals - not as artificial as the example below. Hans ---- local-static.ck ---- class Test { fun void print(float x) { chout <= "Local fun: " <= x <= "\n"; } fun static void print(float x, float y) { chout <= "Static fun: (" <= x <= ", " <= y <= ")\n"; } } Test.print(1, 2); // This call causes the run error. //Test t; //t.print(2); ---- run ---- $ chuck local-static.ck [local-static.ck]:line(11): cannot access member 'Test.print' without object instance... ----

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the novice chucKster trying to navigate the Event class
by Ryan Wieghard 01 Dec '09

01 Dec '09

Hello! So I am trying to design a data structure that is a list of musical events that are composed of duration, amplitude, and a list of four pitches to be assigned to SinOsc's . When I was constructing the idea, I called the atomic units of the lists "events" not knowing that there existed an Event class in chucK. When I researched the Event class, however, I become confused as to whether or not extended that class would be appropriate for what I am trying to achieve. I was wondering if someone could advise me the easiest way of going about creating a list of lists of two ints and a list: ["Event"Object1, "Event"Object2, ...,"Event"ObjectN] where "Event"Object[i] = [int amplitude, int duration, [pitch1,pitch2,pitch3,pitch4]] The idea is that one can simply iterate across the above list of "Event"Objects and assign a bank of four SinOsc's the pitchs 1 through 4; assign an envelope's gain to the amplitude, and advanced time by duration. I apologize if the above is an ugly articulation of my idea. Sincerely, Ryan. -- "Le savant n’étudie pas la nature parce que cela est utile ; il l’étudie parce qu’il y prend plaisir et il y prend plaisir parce qu’elle est belle." - Henri Poincaré

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Semaphore class: wait for timeout or signal, whichever comes first
by Robert Poor 29 Nov '09

29 Nov '09

All: Based on some ideas originally by Tom Lieber, here is a Semaphore class that makes it easy to wait for a specific time OR for an external signal, whichever comes first. I've been using it extensively in my real-time performance code and would like to believe it's well debugged. Presented here in case anyone else might find it useful. Comments, questions welcome. Best, - Rob Poor // semaphore.ck -- wait until a specific time arrives or an external // signal is generated, whichever comes first. // // Sample Usage =================================================== // class TickleSignal extends Object {} // TickleSignal tickle_signal; // Semaphore semaphore; // // repeat(10) { // now + 2::second => time test_end_time; // spork ~ tickler_proc(); // semaphore.wait_for(1::second) @=> Object @ cause; // <<< "semaphore woke due to", cause.toString() >>>; // test_end_time => now; // } // // fun void tickler_proc() { // Std.rand2f(0.0, 2.0)::second => now; // semaphore.signal(tickle_signal); // } // ================================================================ // Author: Robert Poor <rdpoor(a)gmail.com>, November 2009 // TimeoutArrived is used as the <cause> argument for signal() when // the semaphore wakes due to timeout. While it's not neccessary to // define a custom class -- any object can be used as the <cause> // argument to signal() -- a custom class has the nice property that // .toString() will print out the class name. See Sample Usage above // to see how a custom class may be used as the argument to signal(). class TimeoutArrived extends Object {}; // ================================================================ // ================================================================ // The Semaphore class supports waiting for an external signal or a // timeout. public class Semaphore extends Event { // ================================================================ // class constants // TIMEOUT_ARRIVED is a constant returned by wait() to indicate // that the wait() was terminated by timeout rather than by a user // signal. static TimeoutArrived @ TIMEOUT_ARRIVED; new TimeoutArrived @=> TIMEOUT_ARRIVED; // ================================================================ // class methods // ChucK 1.2.1.3 exhibits scheduling bugs when passed time values // with non-zero fractional parts. truncate_time() removes the // fractional part to work around the bug. (See set_timeout(t) // for usage.) fun static time truncate_time(time t) { return t - (t % samp); } // ================================================================ // instance variables Object @ _cause; time _timeout_time; // ================================================================ // public instance methods // ================ // wait() blocks until someone calls signal(cause). It then // returns the cause argument. fun Object wait() { this => now; // wait here for call to signal() return _cause; } // ================ // signal(cause) signals the semaphore, allowing it to return from // a call to wait() with the given cause. fun Semaphore signal(Object cause) { cause @=> _cause; // remember the cause of the signal clear_timeouts(); // inhibit pending timeouts this.broadcast(); // unblock the wait() me.yield(); // allow wait()'ing thread to run return this; } // ================ // set_timeout(time) generates a call to signal(TIMEOUT_ARRIVED) in // the future. If <time> has already passed, no timeout is set // and set_timeout() returns null. fun Semaphore set_timeout(dur duration) { return set_timeout(now + duration); } fun Semaphore set_timeout(time t) { if ((truncate_time(t) => _timeout_time) <= now) return null; spork ~ _timeout_proc(t); me.yield(); return this; } // ================ // clear_timeouts() prevents any pending timeouts from generating // a signal(). // // Implementation note: each call to set_timeout() spawns a new // _timeout_proc(), and once spawned, a proc cannot be killed or // interupted. To inhibit subsequent calls to signal(), we set // _timeout_time to an "impossible" value (i.e. a time in the // past) to inhibit the generation of the signals -- see the // implementation of _timeout_proc() to see why this works. fun Semaphore clear_timeouts() { now - 1::second => _timeout_time; return this; } // ================ // wait_for() and wait_until() combine a call to set_timeout() // followed by a wait(): they will block until the desired time // arrives OR until <this>.signal() is called from another thread, // whichever comes first. fun Object wait_for(dur duration) { return wait_until(now + duration); } fun Object wait_until(time t) { if (set_timeout(t) == null) { return TIMEOUT_ARRIVED; // don't wait() if time already passed } else { return this.wait(); } } // ================================================================ // private methods // _timeout_proc() is spawned in its own thread at each call to // set_timeout(). It blocks until the requested time, and if // the timeout is still current (i.e. now == _timeout_time), it // calls <this>.signal(TIMEOUT_ARRIVED) to unblock the wait(). fun void _timeout_proc(time t) { t => now; // wait until the time arrives // Signal the Semaphore only if this timeout is current if (now == _timeout_time) this.signal(TIMEOUT_ARRIVED); } }

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Filter screaming: danger to hearing
by Tomasz Kaye's brain 28 Nov '09

28 Nov '09

Hello all. I know that Kassen already posted to the list about (what seems like) a filter instability problem in certain situations. But after a conversation with him it seemed that I hadn't conveyed the full nature of the problem clearly, so in this post will try to do that. To recap, here's some code from Kijjaz that demonstrates the problem: PulseOsc osc => BPF filter => blackhole; 20000 => filter.freq; 0.5 => filter.Q; for(int i; i < 100; i++) { <<< "osc: ", osc.last(), " filter: ", filter.last() >>>; samp => now; } The value output by the filter keeps rising. I ran into this problem while i had a similar patch connected to dac instead of to a blackhole. I was wearing headphones, but i took the usual precaution of turning my macbook volume to the lowest level above 0 before running the patch. To my alarm, the resulting screaming sound came through my headphones at top volume anyway. It turns out that when set to any of the volume gradations above 0, the screaming happens at effectively full volume on my macbook. So the point of this extra post is to emphasise that (at least for mac users) the filter screaming issue is currently quite dangerous for hearing/speakers, even if you take (imo) normal sensible precautions before running a patch.

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Re: [chuck-users] Newbie envelope glide confusion
by Perry R Cook 26 Nov '09

26 Nov '09

Envelope e => blah; 2.0 => e.target; This has bitten me more than once. I think a great default behavior for an envelope that has nothing chucked into it would be to yield its current value (as if a 1.0 Step function were chucked into it). That way it would act like an envelope "generator" rather than only an envelope "generator and applier." I'll try to remember to lobby to get this folded into a future version of ChucK. PRC

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Static bug
by Hans Aberg 26 Nov '09

26 Nov '09

For some reason, 'chuck' does not instantiate class static constants until there has been an instantiation of the class itself. Hans ---- static.ck ---- class Test { 3 => static int d; fun static void print() { if (d == 0) chout <= "Nope!\n"; else chout <= "Yep.\n"; } } Test.print(); Test test_; Test.print(); ---- run ---- $ chuck static.ck Nope! Yep. ----

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Newbie envelope glide confusion
by Tomasz Kaye's brain 26 Nov '09

26 Nov '09

I expected that the following code would give a tone that would glide to a new frequency each second. But i think I might be misunderstanding the sync property because i'm not getting any audible output from this. Can anyone explain where i'm going wrong? Envelope env => SawOsc osc => dac; 3::ms => env.duration; 0 => osc.sync; // (0) sync frequency to input, while(true){ 1::second => now; Std.rand2f(100,300) => env.target; }

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Re: [chuck-users] chuck neophyte trying to remove clicks via Envelope patch
by Perry R Cook 25 Nov '09

25 Nov '09

Try this simple fix: Std.rand2f(0,1) => float g; // g => s1.gain; // Don't // g => s2.gain; // set the // g => s3.gain; // oscillator gains // g => s4.gain; // individually // which causes clicks g => e.target; // let the envelope do the smoothing

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chuck neophyte trying to remove clicks via Envelope patch
by Ryan Wieghard 25 Nov '09

25 Nov '09

Hello chucKsters, I am trying to write a simple program that reassigns four sine oscillator's pitch and volume at each iteration through a while(true) loop. I decided i didn't want the clicks at the beginning of each note attack, so I thought that I could remove them by just adding an envelope to ramp up to the gain value for each event. After trying different values for the Envelope time and rate, I can't seem to figure out how to remove the clicks. I apologize as this is probably something obvious that I am blind to in my myopic state. My intuition is that if I increased the rate of the envelope the ramp up to 1 would be smoother and then my speakers wouldn't click. However I am unsure how to adjust the rate as I don't know what range it would be in. Sorry for my n00bishness Ryan. SinOsc s1 => Envelope e=> dac; SinOsc s2 => e => dac; SinOsc s3 => e=> dac; SinOsc s4 => e=> dac; //.... while( true ) { .1 => float t =>e.time; //reassign gain Std.rand2f(0,1) => float g; g => s1.gain; g => s2.gain; g => s3.gain; g => s4.gain; //reassign pitch Std.mtof(instrumentSet1[Std.rand2(0,6)]) => s1.freq; Std.mtof(instrumentSet1[Std.rand2(0,6)]) => s2.freq; Std.mtof(instrumentSet1[Std.rand2(0,6)]) => s3.freq; Std.mtof(instrumentSet1[Std.rand2(0,6)]) => s4.freq; //Advance time by 1 samp e.keyOn(); 1000::ms => now; e.keyOff(); } -- "Le savant n’étudie pas la nature parce que cela est utile ; il l’étudie parce qu’il y prend plaisir et il y prend plaisir parce qu’elle est belle." - Henri Poincaré

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