## Three Beginner Questions

Mar 15 2009 | 11:12 pm
Hi, so I am not a very experienced programmer, but have been learning to develop Max externals in a course I am taking. There's a few things I am trying to figure out in writing my own externals that I hoped the people on this forum could help me with:
1. In one object I am building, I have separate clocks for each outlet. When calling the clock_function, how can I specify which clock/outlet to call? I have tried putting that information into a variable in my object's struct, but prolems arise when multiple clock_functions are modifying that variable at the same time.
2. How do I create anti-aliased wavetables for saw, square and triangle waveforms? I have tried creating them by running each value in the wavetable through a two pole, two zero low pass filter at 20 kHz (coefficents determined through the [filtergraph~] object), with no luck. I also tried implementing the mathematic formulas found here:
only up to the kth partial (where k * f < Nyquist frequency). Also no luck.
3. How do I link an array of values to a [buffer~] object?
Thanks for any help. I look forward to your replies.

• Mar 16 2009 | 11:13 am
Hi CiC,
It seems to me that your second question doesn't necessarily relate to max external development but to dsp programming in general, which usually takes a lot of time to get into. http://www.musicdsp.org/ might be of some help there.
Greets, Mattijs
• Mar 16 2009 | 4:14 pm
thanks matt, that seems like a valuable resource.
i should elaborate on my first question: basically, i ahve X number of inlets, and X number of outlets. When a bang is received in an inlet, a variable number of bangs are output the corresponding outlet. However, when multiple bangs are received in multiple inlets at the same time, the variable in my main object's struct where i store the inlet number (my clock function then uses this to determine what outlet to output bangs from) gets overwritten so only the last value received gets output. what can i do to prevent this?
• Mar 17 2009 | 2:17 am
i found out the answer to my first question: I needed to create a separate struct for a clock/outlet pair, then create an array of these structs within my main struct.