make smoothstep use less flash memory

functions/smoothstep.h

@@ -10,34 +10,37 @@
 // From there it has a smooth transition to 32768, which will be reached at 75% of
 // the blade. If WIDTH is negative, the transition will go the other way.
 
+class SmoothStepBase {
+public:
+  int getInteger(int led) {
+    int x = led * mult_ - location_;
+    if (x < 0) return 0;
+    if (x > 32768) return 32768;
+    return (((x * x) >> 14) * ((3<<14) - x)) >> 15;
+  }
+protected:
+  int mult_;
+  int location_;
+};
+
 template<class POS, class WIDTH>
-class SmoothStep {
+class SmoothStep : public SmoothStepBase {
 public:
   void run(BladeBase* blade) {
     pos_.run(blade);
     width_.run(blade);
     int width = width_.calculate(blade);
-    float mult;
     if (width == 0) {
-      mult = 32768;
+      mult_ = 32768;
+      location_ = blade->num_leds() * pos_.calculate(blade);
     } else {
-      mult = 32768 * 32768.0 / width / blade->num_leds();
+      mult_ = 32768 * 32768 / width / blade->num_leds();
+      location_ =  32768 * pos_.calculate(blade) / width - 16384;
     }
-    mult_ = mult;
-    location_ = blade->num_leds() * mult * (pos_.calculate(blade) - width/2) / 32768;
-  }
-
-  int getInteger(int led) {
-    int x = led * mult_ - location_;
-    if (x < 0) return 0;
-    if (x > 32768) return 32768;
-    return (((x * x) >> 14) * ((3<<14) - x)) >> 15;
   }
 
   PONUA SVFWrapper<POS> pos_;
   PONUA SVFWrapper<WIDTH> width_;
-  int mult_;
-  int location_;
 };
 
 #endif