1 files changed, 53 insertions(+), 3 deletions(-)

M gestvm.org

@@ 279,11 279,11 @@ SKFLT gestvm_tick(gestvm *gvm, SKFLT cnd)
 
     cnd = rephasor_tick(gvm, cnd);
 
-    /* VM process */
+    /* VM process! */
 
     vm_tick(gvm, cnd);
 
-    /* Interpolate */
+    /* Interpolate! */
 
     out = interpolate(gvm, cnd);
 


@@ 1316,6 1316,21 @@ gestvm_behavior behavior;
 #+BEGIN_SRC c
 gvm->behavior = b_linear;
 #+END_SRC
+
+The =a= value caches the last alpha value used for
+interpolation. Intended to be used for applications
+that want to build on top of or enhance the gesture
+synthesizer.
+
+#+NAME: gestvm
+#+BEGIN_SRC c
+SKFLT a;
+#+END_SRC
+
+#+NAME: init
+#+BEGIN_SRC c
+gvm->a = 0;
+#+END_SRC
 ** Some Behaviors
 Some behaviors include linear, step, and glissando.
 


@@ 1382,7 1397,8 @@ static SKFLT interpolate(gestvm *gvm, SKFLT phs)
 {
     SKFLT a;
     a = gvm->behavior(gvm, phs);
-
+    /* cache interpolation value */
+    gvm->a = a;
     if (gvm->interp)
         return (1.0 - a)*gvm->cur + a*gvm->nxt;
     return a;


@@ 1431,6 1447,40 @@ static gestvm_behavior find_behavior(int id)
     return b;
 }
 #+END_SRC
+** Get Last Interpolator Values (for extending GestVM)
+GestVM will cache the state of the last call
+to =gestvm_tick=. By the time it comes to the interpolator,
+this boils down to 2 values (called =x= and =y=), and some
+interpolation coefficient.
+
+This function retrieves these copies these values to their
+respective variables.
+
+#+NAME: funcdefs
+#+BEGIN_SRC c
+void gestvm_get_last_values(gestvm *gvm,
+                            SKFLT *x,
+                            SKFLT *y,
+                            SKFLT *a);
+#+END_SRC
+
+The x and y variables are substitutes for cur (current)
+and nxt (next). Outside the scope of gestvm, these
+terser variable names align more with the more cannonical
+mathematical notations for interpolation.
+
+#+NAME: funcs
+#+BEGIN_SRC c
+void gestvm_get_last_values(gestvm *gvm,
+                            SKFLT *x,
+                            SKFLT *y,
+                            SKFLT *a)
+{
+    *x = gvm->cur;
+    *y = gvm->nxt;
+    *a = gvm->a;
+}
+#+END_SRC
 * Weight
 ** Overview
 This is an optional signal generator used to influence