That had occurred to me as I'm actually using ftmorf to morph between wavetables for my instrument. The only thing was I wanted to be able to "twist" the phasor that reads the tables as well as bending and stretching it. After thinking about it though this could work using a number of ftmorfs together. One could make a the bending / stretching log /exp phasor, another could morph between this wave and the "twist" wave, something more like a square wave. It sounds a bit mad but I'll give it a go :) 

-- 
Edward Costello


On Monday 10 December 2012 at 12:36, Oeyvind Brandtsegg wrote:

> ... another stray thought,
> could you make one log table and one exponential table, and then morph between them using ftmorf?
> Oeyvind
> 
> 
> 2012/12/10 Edward Costello <edwardcostello@gmail.com (mailto:edwardcostello@gmail.com)>
> > Thanks, yes I figured that just having it do the calculation constantly would give a more consistent performance, I was just worried about cpu as I am planning on having three of these going at once. In retrospect though yeah writing all the values to the table although costs almost nothing once the table is written the initial burst of calculations is a bit much to ask my cpu!  
> > The pdhalf opcode looks interesting but yeah I was looking to have a smoother wave distortion for my program, 
> > Cheers
> > 
> > -- 
> > Edward Costello
> > 
> > 
> > On Sunday 9 December 2012 at 21:53, Oeyvind Brandtsegg wrote:
> > 
> > > Not sure, but I wonder if it would perhaps be more efficient (well, give a more stable usage anyhow) to calculate the mapping at audio rate as needed instead of calculating all values and writing to table whenever the parameter settings change. The actual calculation does not look too heavy, but doing a k-rate loop over a whole table can easily cost a lot, also depending on table size of course.
> > > Just as a stray thought, perhaps you could also use the pdhalf opcode for something here? It would be linear segment instead of smooth...
> > > best
> > > Oeyvind
> > > 
> > > 
> > > 2012/12/8 Ed Costello <edwardcostello@gmail.com (mailto:edwardcostello@gmail.com)>
> > > > Hi list,
> > > > 
> > > > I'm making a wavetable synth and I have implemented a phase distortion opcode that controls where and at what rate parts of the wavtables tables are read. The phase distortion opcode creates a 'wavereader' table that is read using a phasor, this in turn is then plugged into a table read opcode which reads the actual audio waveform. 
> > > > 
> > > > It all works fine except that when I change the phase distortion parameters it takes a load of cpu to rewrite the phase distortion table. I was just wondering could anyone suggest a more efficient way of implementing this. The opcode is this: 
> > > > 
> > > > 
> > > > opcode LogarithmicToExponentialCurve, i, kki
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > k_Bend, k_Stretch, i_FTSize xin
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > k_BendTracker init -1
> > > > 
> > > > 
> > > > k_StretchTracker init -1
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > gi_LogExpTable ftgen 0, 0, i_FTSize, -2, 0
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > if k_BendTracker == k_Bend || k_StretchTracker == k_Stretch then
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > kgoto End
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > elseif k_BendTracker != k_Bend || k_StretchTracker != k_Stretch then
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > k_BendTracker = k_Bend
> > > > 
> > > > 
> > > > k_OneMinusBend = 1-k_Bend
> > > > 
> > > > 
> > > > k_Index = 0
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > Loop:
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > k_X = k_Index / i_FTSize
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > k_TableValue = ((k_X^k_Stretch * k_OneMinusBend)+((k_X^(1/k_Stretch)) * k_Bend))
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > tabw k_TableValue, k_Index, gi_LogExpTable
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > loop_le k_Index, 1, i_FTSize, Loop
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > endif
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > End:
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > xout gi_LogExpTable
> > > > 
> > > > 
> > > > endop
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > Thanks,
> > > > 
> > > > 
> > > > Ed
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > -- 
> > > 
> > > Oeyvind Brandtsegg
> > > Professor of Music Technology
> > > NTNU
> > > 7491 Trondheim
> > > Norway
> > > Cell: +47 92 203 205 (tel:%2B47%2092%20203%20205)
> > > 
> > > http://flyndresang.no/
> > > http://www.partikkelaudio.com/
> > > http://soundcloud.com/brandtsegg
> > > http://soundcloud.com/t-emp
> > 
> 
> 
> 
> -- 
> 
> Oeyvind Brandtsegg
> Professor of Music Technology
> NTNU
> 7491 Trondheim
> Norway
> Cell: +47 92 203 205
> 
> http://flyndresang.no/
> http://www.partikkelaudio.com/
> http://soundcloud.com/brandtsegg
> http://soundcloud.com/t-emp