NAME

makegen - create a function table

SYNOPSIS

makegen(table_number, function_type, table_size, arg1 [, arg2, ... ])

DESCRIPTION

Call makegen from a script to create a function table, which you can use to control an RTcmix instrument or to store values for use in the script. For example, RTcmix instruments require you to make function tables for waveforms, envelopes, and so on. Your script can access tables with the sampfunc and sampfunci script commands. You can view functions with the fplot command.

NOTE: Much of the functionality of makegen has been duplicated and extended by maketable and the new (in RTcmix 4.0) table-handle scheme.

ARGUMENTS

table_number

A numeric ID for the table. Instruments require a specific ID for tables that they use. For example, most instruments require that their amplitude envelope be table number 1. WAVETABLE wants its waveform in table number 2, and so on. See documentation for instruments to find out what each requires.

Many function types will normalize the table values so that they fall between -1 and 1. To prevent this, put a negative sign in front of the table number (e.g., makegen(-1, 18, 2000, ...).

function_type

A numeric code indicating an algorithm that produces a specific kind of table. For example, 10 creates a waveform, 20 creates a table of random numbers, etc. See the summary of function types below.

table_size

The size of the function table: how many numbers it stores. For most tables, you can use 1000 or 2000 here. You might want to use more or less, depending on the specific purpose. (For example, you might want only 50 random numbers, so you would use function type 20 and set the table size to 50.) There is no requirement that this size be a power of two.

arg1, arg2, ...

Any number of arguments that define the table. These depend on the function type. See documentation for each type. A summary of types appears below.

Note that the number of arguments used to define the table is independent of the table size. So, depending on the function type, you can create a table with a size of 2000 using only one or two arguments.

Summary of Function Types

We refer to the different types as ``gen 1,'' ``gen 10,'' etc.

gen 1: fills a function table with samples from a sound file.
gen 2: fills a function table with numbers specified in the script or in a text file.
gen 3: fills a function table with numbers from a data file.
gen 4: makes a function having any number of line segments, with adjustable curvature for each segment, and defined in terms of time,value pairs.
gen 5: makes a function having any number of exponential line segments.
gen 6: makes a function having any number of straight line segments, defined in terms of time,value pairs.
gen 7: makes a function having any number of straight line segments.
gen 9: makes a function having one cycle of an arbitrary waveform, defined by triplets of floating-point partial number, amplitude, and phase.
gen 10: makes a function having one cycle of an arbitrary waveform, defined by harmonic partials and their relative strengths.
gen 17: makes a transfer function using Chebyshev polynomials.
gen 18: works like gen 6, except it never normalizes the table to fit between -1 and 1.
gen 20: fills a function table with random numbers using several different distributions (even, low-weighted linear, triangle linear, gaussian, cauchy, etc.).
gen 24: makes a function having any number of straight line segments, defined in terms of time,value pairs. (This is subtly different from gen 6, but it's not clear why anyone would care.)
gen 25: makes a window function using several different common window types (hanning, hamming, etc.).

EXAMPLES

   makegen(1, 6, 1000, 0, 0, 1, 1)

Table number 1 will contain a straight line from 0 to 1; the table will have 1000 elements.

   makegen(-5, 10, 2000, 0.5)

Table number 5 will contain a sine wave at half amplitude, ranging from -0.5 to 0.5. The negative sign before the table number prevents the table from being normalized (scaled to fall between -1 and 1). The table will have 2000 elements.

NOTES

If you call makegen again with the same table_number, then it replaces the old table, but only for instruments that have not yet been called in the script:

   makegen(2, 10, 1000, 1)   /* sine wave */
   WAVETABLE(start, dur, amp, freq)

   makegen(2, 10, 1000, 1, 1, 1, 1, 1, 1, 1, 1, 1)  /* buzzy wave */
   WAVETABLE(start, dur, amp, freq)

The second call to makegen replaces the sine wave with a buzzy wave. But the first WAVETABLE note continues to use the sine wave. It would still work this way even if the second note were set to start playing before the first.