tabrowlin

Abstract

Copy a row from an f-table to another, interpolating between rows

Description

This opcode assumes the use of a table, which is a simple 1D array, to hold a 2D matrix with a given row length. Assuming such a 2D table containing multiple rows of sampled streams (for instance, the amplitudes of a set of oscilators, sampled at a regular interval), this opcode can extract one row (or a slice of a row) of that data with linear interpolation between adjacent rows (if row is not a whole number) and place the result in another table

Syntax

tabrowlin krow, ifnsrc, ifndest, inumcols [, ioffset=0, istart=0, iend=0, istep=1

Arguments

krow: the row to read. It can be a fractional number, in which case the row will be linearly interpolated with the next row
ifnsrc: The table index to copy data from
ifndest: The table index to copy data to (should be able to old one row of data)
inumcols: The number of columns a row has, in the source table
ioffset: an offset to where the 2D data starts (used to skip a header, if present)
istart: start index to read from (refers to the row)
iend: end index to read from the row (not inclusive, can't exceed inumcols)
istep: step used to read along the row

Output

This opcode has no outputs. The interpolated data is placed in ifndest

Execution Time

Performance

Examples

<CsoundSynthesizer>
<CsOptions>
-odac     ;;;realtime audio out
</CsOptions>
<CsInstruments>


/* 

If reading out of bounds a PerformanceError will be raised. Because we
interpolate between rows, the last row that can be read is

  maxrow = (ftlen(ifnsrc)-ioffset)/inumcols - 2

*/

sr = 44100
ksmps = 128
nchnls = 1
0dbfs  = 1

instr 1
  ; just a simple test of the bare functionality
  ; generate a 4x3 table
  isource ftgentmp 0, 0, -12, -2, \
       0,  1,  2,  3,   \
      10, 11, 12, 13,   \
      20, 21, 22, 23
  ; create an empty table able to hold one row (4 elements)
  idest ftgentmp 0, 0, -4, -2, 0
  print ftlen(isource)
  ; we exceed the max. row to show what happens (the row is clipped
  ; to the max row possible and a message is printed to show the error)
  krow linseg 0, p3, 2.05
  printk2 krow, 20
  tabrowlin krow, isource, idest, 4
  ftprint idest, -1
endin

</CsInstruments>
<CsScore>
i 1 0 2
</CsScore>
</CsoundSynthesizer>

Credits

Eduardo Moguillansky, 2019