wterrain2

A wave-terrain synthesis opcode using different curves

It enhances the wterrain opcode by providing some more curves, krate table parameters and a parameter for rotating the curve.

Syntax

aout wterrain2 kamp, kcps, kx, ky, krx, kry, krot, ktab0, ktab1, \
               kcurve, kcurveparam

Performance

ktabx, ktaby -- The two tables that define the terrain - they can be changed at krate.

The output is the result of traversing at frequency kcps the curve kcurve with the parameter kcurveparam (see below), scaled with krx and kry and centered at kx, ky on the terrain and rotated around the center with krot radians.

kcurve=0: ellipse as in the wterrain opcode but with a special extension. kcurveparam controls a speed change of the traversing point. The formula is:

fx(t) = kx + krx * sin( t + kcurveparam * sin(t) )
fy(t) = ky + kry * cos( t + kcurveparam * sin(t) )

kcurve=1: lemniskate - this is a simple 8. here also the kcurveparam controls a speed change of the traversing point. The formula is:

fx(t) = kx + krx * cos( t + kcurveparam * sin(t) )
fy(t) = ky + kry * sin( t + kcurveparam * sin(t) )  * cos( t + kcurveparam * sin(t) )

kcurve=2: limacon

fx(t) = kx + krx * sin(t) * (cos(t) + kcurveparam);
fy(t) = ky + kry * cos(t) * (cos(t) + kcurveparam);

limacon curve with different parameters

kcurve=3: cornoid

fx(t) = kx + krx * cos(t) * cos(2*t)
fy(t) = ky + kry * sin(t) * (kcurveparam + cos(2*t))

cornoid with different parameters

kcurve=4: trisectrix (Ceva)

fx(t) = kx + krx * cos(t) * (1+kcurveparam*sin(2*t));
fy(t) = ky + kry * sin(t) * (1+kcurveparam*sin(2*t));

trisectrix curve with different parameters

kcurve=5: scarabeus

fx(t) = kx + krx * cos(t) * (1+kcurveparam*sin(2*t));
fy(t) = ky + kry * sin(t) * (1+kcurveparam*sin(2*t));

scarabeus curve with different parameters

kcurve=6: folium

fx(t) = kx + krx * cos(t) * cos(t) * (sin(t)*sin(t) - kcurveparam);
fy(t) = ky + kry * sin(t) * cos(t) * (sin(t)*sin(t) - kcurveparam);

folium with different parameters

kcurve=7: Talbot curve

fx(t) = kx + krx * cos(t) * (1 + kcurveparam * sin(t)*sin(t));
fy(t) = ky + kry * sin(t) * (1 - kcurveparam - kcurveparam*cos(t)*cos(t));

Talbot curve with different parameters

Examples

Here is an example of the wterrain2 opcode. It uses the file wterrain2_1.csd.

<CsoundSynthesizer>
<CsOptions>
-odac -d
</CsOptions>

<CsInstruments>
sr     = 48000
ksmps  = 32
nchnls = 2
0dbfs  = 1

gisine ftgen 0,0,2^12,10,1
gScurves[] fillarray "ELLIPSE ", "LEMNISKATE ", "LIMACON ","CORNOID ","TRISEXTIC ","SCARABEUS ","FOLIUM ","TALBOT "

instr 1 
prints gScurves[p4]
kdclk init 0
kdclk   linsegr  0, 0.1, 1, p3-0.02, 1, 0.9, 0
kparam init 0
krot init 0
krot linseg 0,p3,6.28 ; ROTATE THE CURVE SLOWLY
kparam linseg 0,p3,4 ; INCREASE CURVEPARAMETER

asigL wterrain2 0.5, 110, 0.5, 0.5, 0.8, 0.4, krot, gisine, gisine, p4, kparam
; LET THE POINT FOR RIGHT RUNNING BACKWARDS FOR A LITTLE STEREO EFFECT
asigR wterrain2 0.5, -110, 0.5, 0.5, 0.8, 0.4, krot, gisine, gisine, p4, kparam
asigR dcblock asigL
asigL dcblock asigR
asigL*=kdclk
asigR*=kdclk
aL,aR reverbsc asigL, asigR, 0.6, 15000, 44100, 0.5, 1
outs aL,aR

endin

</CsInstruments>

<CsScore>

i 1 0 40 0 ; ELLIPSE
i 1 41 40 1; LEMNSIKATE
i 1 82 40 2; LIMACON
i 1 123 40 3; CORNOID
i 1 164 40 4; TRISEXTIC
i 1 205 40 5; SCARABEUS
i 1 246 40 6; FOLIUM
i 1 287 40 7; TALBOT

e
</CsScore>
</CsoundSynthesizer>

Here is an other example of the wterrain2 - a sound fugue. It uses the file wterrain2_2.csd.

<CsoundSynthesizer>
<CsOptions>
-odac -d
</CsOptions>

<CsInstruments>
sr     = 48000
ksmps  = 32
nchnls = 2
0dbfs  = 1

gisine ftgen 0,0,2^12,10,1

instr 1

kamp adsr 0.1,0.01,1,10

; THE MODULATION PARAMETERS 
krot linseg 0,p3,6.28 ; ROTATE
kparam randc 2.5,0.1,0.993 ; CONTROL CURVEPARAMETER WITH CUBIC RANDOM 
kx linseg 0,p3/2,1,p3/2,0 ; MOVE HORIZONTAL THROUGH THE TERRAIN
ky linseg 0,p3,1 ; MOVE VERTICAL THROUGH THE TERRAIN

; TRY THE OTHER CURVES AS WELL 
asigL wterrain2 0.2, 55*p4, kx, ky, 0.5, 0.4, krot, gisine, gisine, 5, kparam
asigR wterrain2 0.2, -55*p4, kx, ky, 0.5, 0.4, krot, gisine, gisine, 5, kparam

asigR dcblock asigL
asigL dcblock asigR
asigL butterlp asigL,9000
asigR butterlp asigR,9000
aL,aR reverbsc asigL, asigR, 0.7, 15000, 44100, 0.5, 1
outs aL*kamp*p5,aR*kamp*p5

endin

</CsInstruments>

<CsScore>

i 1 0 300 1 1
i 1 1 300 7 0.4
i 1 2 299 [9/2] 0.4
i 1 3.1 296.9 [16/3] 0.45
i 1 4.3 295.7 [27/4] 0.5
i 1 6.9 292.1 6 0.5 

e
</CsScore>
</CsoundSynthesizer>

See Also

Wave Terrain Synthesis

Credits

Author: Christian Bacher
New in version 6.15