4 files changed, 119 insertions(+), 0 deletions(-)

A examples/expon.lil
A examples/expon.tal
M examples/render.sh
M gestvm.org

@@ 0,0 1,21 @@
+
+gestvmnew gvm
+
+gestvmload [grab gvm] expon.rom
+
+
+phasor 2 0
+hold zz
+regset zz 0
+
+gestvmnode [grab gvm] [gestvmsym expon.rom mel] [regget 0]
+
+mtof zz
+blsaw zz
+
+butlp zz 800
+
+unhold [regget 0]
+
+wavout zz expon.wav
+computes 15

@@ 0,0 1,31 @@
+%NUM { #24 DEO }
+%DEN { #25 DEO }
+%NEXT { #26 DEO }
+%NOTE { #3c ADD NEXT }
+%BHVR { #27 DEO }
+
+|0100
+
+@mel
+
+( exponential convex low )
+#00 NOTE BRK
+#01 NUM #04 DEN #07 BHVR #0c NOTE BRK
+#01 DEN #01 BHVR
+
+( exponential convex high )
+#00 NOTE BRK
+#01 NUM #04 DEN #08 BHVR #0c NOTE BRK
+#01 DEN #01 BHVR
+
+( exponential concave low )
+#00 NOTE BRK
+#01 NUM #04 DEN #09 BHVR #0c NOTE BRK
+#01 DEN #01 BHVR
+
+( exponential concave high )
+#00 NOTE BRK
+#01 NUM #04 DEN #0a BHVR #0c NOTE BRK
+#01 DEN #01 BHVR
+
+;mel JMP2

@@ 9,3 9,4 @@ render () {
 render sequence
 render skew
 render weight
+render expon

@@ 1455,6 1455,60 @@ static SKFLT b_gliss(gestvm *gvm, SKFLT a)
     return a;
 }
 #+END_SRC
+*** Exponential
+Exponetial behaviors apply various kinds of exponential
+curves. There are two main types of exponential curves:
+convex and concave. A convex exponential curve will more
+quickly grow, while a concave curve will only grow at the
+end, and mostly stay at a lower state.
+
+Of those types, there are two different slopes: a "high"
+slope provides a sharp incline, while a "low" slope
+provides a more regular exponential curve.
+A convex high curve will quickly rise like an attack
+envelope, while a concave
+high will wait until the very last moment to rise to the
+next value.
+
+#+NAME: funcdefs
+#+BEGIN_SRC c
+static SKFLT expmap(SKFLT in, SKFLT slope);
+static SKFLT b_expon_convex_high(gestvm *gvm, SKFLT a);
+static SKFLT b_expon_convex_low(gestvm *gvm, SKFLT a);
+static SKFLT b_expon_concave_high(gestvm *gvm, SKFLT a);
+static SKFLT b_expon_concave_low(gestvm *gvm, SKFLT a);
+#+END_SRC
+
+#+NAME: funcs
+#+BEGIN_SRC c
+static SKFLT expmap(SKFLT in, SKFLT slope)
+{
+    return (1 - exp(in*slope)) / (1 - exp(slope));
+}
+
+static SKFLT b_expon_convex_high(gestvm *gvm, SKFLT a)
+{
+    return expmap(a, -4);
+}
+
+static SKFLT b_expon_convex_low(gestvm *gvm, SKFLT a)
+{
+
+    return expmap(a, -1);
+}
+
+static SKFLT b_expon_concave_high(gestvm *gvm, SKFLT a)
+{
+
+    return expmap(a, 4);
+}
+
+static SKFLT b_expon_concave_low(gestvm *gvm, SKFLT a)
+{
+    return expmap(a, 1);
+}
+#+END_SRC
+
 ** Main Function
 #+NAME: static_funcdefs
 #+BEGIN_SRC c


@@ 1510,6 1564,18 @@ static gestvm_behavior find_behavior(int id)
         case 6:
             b = b_gate_rel_50;
             break;
+        case 7:
+            b = b_expon_convex_low;
+            break;
+        case 8:
+            b = b_expon_convex_high;
+            break;
+        case 9:
+            b = b_expon_concave_low;
+            break;
+        case 10:
+            b = b_expon_concave_high;
+            break;
         default:
             break;
     }