Pd-dev September 2002

pd-dev@lists.iem.at

27 participants
37 discussions

arbitrary start position with tabwrite~
by Chris McCormick 13 Nov '02

13 Nov '02

Hi Miller, list, I've made the following tiny patch to tabwrite~ so i can begin recording to a table at an arbitrary sample position. instead of banging tabwrite~ you can send it 'start 123' and it will start recording at sample position 123. I need this because i want to make long audio recordings but i might not want to start recording the whole thing at the beginning. Regards, Chris. chr15m:~/software/installed/pd-0.35-0/src$ diff d_array.c d_array.c.old 96,100d95 < static void tabwrite_tilde_start(t_tabwrite_tilde *x, t_floatarg fstart) < { < x->x_phase = fstart; < } < 139,140d133 < class_addmethod(tabwrite_tilde_class, (t_method)tabwrite_tilde_start, < gensym("start"), A_FLOAT, 0); _________________________________ chris(a)mccormick.cx http://www.mccormick.cx http://www.sciencegirlrecords.com

8 11

TCL/TK tags
by Thomas Grill 07 Nov '02

07 Nov '02

Hi all, as i am new to TCL/TK, i encounter problems with it all the time. Here is a simple example, the creation of two rectangles (please don't mind the strange specifiers... they are generated from pointer values) ----------------- .x8ff8c8.c create rectangle 69 64 169 164 -tags ec0858GUI -width 2 -fill #00ff00 -outline #00ff00 .x8ff8c8.c create rectangle 89 84 139 134 -tags ec08c8GUI -fill #0000ff that's just ok... the second (slightly smaller one) is displayed on top of the first one. ------------------- Now, i'd like to add an additional tag (ec0728GRP) to each of them, to e.g. move them with a single command .x8ff8c8.c create rectangle 69 64 169 164 -tags ec0858GUI -width 2 -fill #00ff00 -outline #00ff00 .x8ff8c8.c addtag ec0728GRP withtag ec0858GUI .x8ff8c8.c create rectangle 89 84 139 134 -tags ec08c8GUI -fill #0000ff .x8ff8c8.c addtag ec0728GRP withtag ec08c8GUI Now, only the first (larger) one is visible... why? ------------------------------ many thanks, Thomas

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loading abstractions into objcts...?
by Olaf Matthes 01 Oct '02

01 Oct '02

Hi developers, say I have an abstraction having one (control) inlet and one (control) outlet and an external with the same number of inlets/outlets that does nothing by it's own. What I now would like to do is to 'load' the abstraction into may external instead of loading it as a 'stand-alone object'. Thus my external would always be there but I could load different abstractions into it. Would that be possible without having to write a second Pd in an external? I tried some things but it all ended up in a new canvas popping up containing my abstraction (or parts of it or even parts of the calling patch...). please enlighten me! Olaf

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Hello
by Riccardo Trocca 30 Sep '02

30 Sep '02

Hello, I'm almost a newbye to Pure-Data even if I had some experience with MAX/MSP. I've got experience in building systems for real-time processing of video (live or movies) in order to generate data for music/sound synthesis. I'm looking at writing PD externals to do that. I'd like to know if it is possible (and how) to add a new datatype to PD, ore, some advice on how to implement my ideas. Reading the documentation I've seen that there are very few datatypes: number, symbol, pointer and audio buffers. Given that I'm just beginning to tackle the problem may be I'm asking some FAQ, anyway... I can't understand what is the pointer datatype. A symbol seems to be "just" a string. Can I add a value a pointer to a data structure? It is possible to build something as audio buffers (image data type, or multidimensional array)? Does that require modifications to PD? The system I'm working on, allows to create a chain of processing on images, then when the system begins to run there is an init phase where each element of the processing chain is told what kind of images it will receive, it initializes itself and its internal buffers, and then starts working everytime it receives data. I think that it is more or less what happens with the audio chain in PD. Framestein has a different approach given what I've seen. Something similar seems to be GridFlow, but I'm having a hard time trying to understand its inner workings. Well if somebody can give me some pointer to start think about... thanks Riccardo Trocca

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Re: [PD-dev] signal external and IOhannes's tutorial
by Adam T. Lindsay 25 Sep '02

25 Sep '02

Olaf, thanks for your reply. I'll continue to flaunt my ignorance on the public list with my reply... Olaf Matthes said this at Wed, 25 Sep 2002 15:32:13 +0200: >"Adam T. Lindsay" schrieb: > >> >Optimization of the DSP-tree tries to avoid unnecessary copy-operations. >> >Therefore it is possible, that in- and out-signal are located at the same >> >address in the memory. In this case, the programmer has to be careful not >> >to write into the out-signal before having read the in-signal to avoid >> >overwriting data that is not yet saved. >> >> <http://iem.kug.ac.at/pd/externals-HOWTO/ >> node6.html#SECTION00065000000000000000> >> >> To me, this is a bit ambiguous (and my German officemate couldn't help >> with the lang-de version). Who does the optimization? > >Pd does. It uses 'the same address in memory'. Thus you have to read in a >sample before writing a sample. Writing just overwrites the input samples... >In case you want 'silence' you have to set all samples to 0. Otherwise you >would hear your input signal! > >Using this method saves a lot of memory allocation. Thanks. That's clear now. I guess I'm now confused by sending pointers to each "in" and "out" buffer, but I can sort of see the rationale. But more importantly, how do I pass these pointers to enforce an in-place computation on the part of the signal processing network? Should I do something that looks "wrong," like: void inPlace_dsp(t_inPlace *x, t_signal **sp) { dsp_add(inPlace_perform, 4, x, sp[0]->s_vec, sp[0]->s_vec, sp[0]->s_n); // in and out are the same } t_int *inPlace_perform(t_int *w) { t_inPlace *x = (t_inPlace *)(w[1]); t_sample *in = (t_sample *)(w[2]); t_sample *out = (t_sample *)(w[2]); int n = (int)(w[3]); /* etc... */ return (w+6); } Thanks for the help, adam -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Adam T. Lindsay atl(a)comp.lancs.ac.uk Computing Dept, Lancaster University +44(0)1524/594.537 Lancaster, LA1 4YR, UK Fax:+44(0)1524/593.608 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

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newbie external experiments
by André Schmidt 25 Sep '02

25 Sep '02

hi devs, (its me again:) ok, after succesfully compiling the examples from IOhannes external-how-to's i tried to implement my "own" code. but as i have VERY little clou what i'm doing i would like to have some help here. the working (non PD) c code is here: ---------------------------------------------------- #include <stdio.h> #define bits 8 char* byte2BinStr(char *strOut, unsigned char byteIn) { int i; int d; for(i = 0; i < bits; i++) { d = (byteIn & 0x80); byteIn = byteIn << 1; strOut[i] = (d ? '1' : '0'); } return strOut; } int main(void) { int a; char strBB[4*bits+1]; scanf("%d", &a); printf("%s", byte2BinStr(strBB, a)); return 0; } -------------------------------------------- actually it's not 100% my own code (found the bit conversion from newsgroup) but i implemented it so that it ask an integer from user and gives a 8bit binary string out... then i tried to convert it to be used on pd, converting incoming ints to symbol strings. this is what i adapted from v2db.c (iemlib): ---------------------------------------------- #include "m_pd.h" #define bits 8 char strBB[4*bits+1]; static t_class *bitstr_class; typedef struct _bitstr { t_object x_obj; t_int i_byte; t_outlet *s_out; } t_bitstr; char* byte2BinStr(char *strOut, unsigned char byteIn) { int i; int d; for(i = 0; i < bits; i++) { d = (byteIn & 0x80); byteIn = byteIn << 1; strOut[i] = (d ? '1' : '0'); } return strOut; } static void bitstr_symbol(t_object *x, t_int i) { outlet_symbol(x->ob_outlet, byte2BinStr(strBB, i)); } static void *bitstr_new(void) { t_object *x = (t_object *)pd_new(bitstr_class); outlet_new(x, &s_symbol); return (x); } void bitstr_setup(void) { bitstr_class = class_new(gensym("bitstr"), bitstr_new, 0, sizeof(t_object), 0, 0); class_addsymbol(bitstr_class, (t_method)bitstr_symbol); class_sethelpsymbol(bitstr_class, gensym("help-bitstr")); } ----------------------------------------- yes, you may laugh over my code :) it's just what i logically thougt would go. please let me know if i'm even on the right way, but i know i have MUCH to learn and the IOhannes how-to is still too high for me :(. for the basics i've gone trough this http://www.iota-six.co.uk/c/01_intro.htm (very good for beginners). would be nice if some1 could point me what i should learn before i "fully" understand pd-external coding, i know i don't have to know *ALL* from c. as i ONLY want to code externals for PD. yes, i know this is WAY over my head, but i like extreme challenges... cheers, slowing down -andre

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signal external and IOhannes's tutorial
by Adam T. Lindsay 25 Sep '02

25 Sep '02

Hi all. I've been trying to work through Johannes's useful tutorial on PD externals. In the signal example, English version, he says: >Optimization of the DSP-tree tries to avoid unnecessary copy-operations. >Therefore it is possible, that in- and out-signal are located at the same >address in the memory. In this case, the programmer has to be careful not >to write into the out-signal before having read the in-signal to avoid >overwriting data that is not yet saved. <http://iem.kug.ac.at/pd/externals-HOWTO/ node6.html#SECTION00065000000000000000> To me, this is a bit ambiguous (and my German officemate couldn't help with the lang-de version). Who does the optimization? Does PD optimize the DSP tree such that it creates in-place operations, and therefore the programmer must be aware of this happening? Or does it mean that the programmer has the option of optimizing the DSP tree by doing computations in place, as long as they do it carefully? I'm sorry if I come across as pedantic about language. I'm honestly confused, and the API I'm trying to write a glue to actually encourages in-place DSP computation. So if there is a way of interfacing with PD in that way, I'd be really happy. Thanks, adam -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Adam T. Lindsay atl(a)comp.lancs.ac.uk Computing Dept, Lancaster University +44(0)1524/594.537 Lancaster, LA1 4YR, UK Fax:+44(0)1524/593.608 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

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pd externals makefile help for newbie [win32]
by André Schmidt 24 Sep '02

24 Sep '02

hi devs, i hope i'm not buggin you too much (again:) with my newbish questions, but i want to get started with little trouble as possible. so, got MSVC++6 and i managed to compile the foos in .../6.externs/ with 'nmake' after i changed the right paths in the makefile. and yes, they really worked :). this was my first time i compiled c/c++ from the commandline (not including my 1 and only time i succesfully compiled pd on linux:) so this makefile thing is a quite mystery to me but i assume it has all the settings that an IDE would have in it's menus, or similar. ok, for starters i want to compile the "hello world" external from http://iem.kug.ac.at/pd/externals-HOWTO/node3.html but i dont know what i should write in the makefile. before i start to TAE with the makefile from the foo examples i thought maybe some1 could explain or give a good www-link about the makefile... thnx -andre (boldly going where i've newer been)

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c/c++ compilers
by André Schmidt 23 Sep '02

23 Sep '02

hi devs, i'm now starting to learn the wonders of c/c++ coding on windows and was wondering what compilers/IDE are you all using. or what compilers you could recommend for a beginner. i would like to avoid using M$-VC or other commercial products... i found something interesting: http://www.bloodshed.net/devcpp.html (i'm more a GUI person:) and downloaded the version 5(beta!) and tried to make the "helloworld" external @ http://iem.kug.ac.at/pd/externals-HOWTO/node3.html but i only get errors... so it would be nice if some1 would test/know if this dev-c++ is "usable" for pd/externals (i assume the errors didnt have nothing to do it being beta) thnx -andre ps. is there a "how to" for compiling pd on windows (using NOT commercial compilers)

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Few improvements to "grid"
by umbpux＠tin.it 23 Sep '02

23 Sep '02

Hello Yves. I added the following methods to grid: bang (send current values) values (updates cursor position by value instead of coordinates) valuemotion (same but with dxvalue and dyvalue) xvalues (same as values but doesn't forward the value on the outlets) xvaluemotion I attached the grid.c file. I may implement some other changes to grid that I'd like to use. Should I keep them on my HD or can I contribute to the original external? Could I use the CVS or will I make you mad with me? Bests, Maurizio Umberto Puxeddu.

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Pd-dev September 2002