v1.4.4

source/core/StarPeriodic.hpp

@@ -0,0 +1,98 @@
+#ifndef STAR_PERIODIC_HPP
+#define STAR_PERIODIC_HPP
+
+#include "StarMathCommon.hpp"
+#include "StarRandom.hpp"
+
+namespace Star {
+
+// Perform some action every X ticks.  Setting the tick count to 0 means never
+// perform the action, 1 performs the action every call, 2 performs the action
+// every other call, and so forth.
+class Periodic {
+public:
+  Periodic(unsigned everyXSteps = 1)
+    : m_counter(0), m_everyXSteps(everyXSteps) {}
+
+  unsigned stepCount() const {
+    return m_everyXSteps;
+  }
+
+  void setStepCount(unsigned everyXSteps) {
+    m_everyXSteps = everyXSteps;
+    if (everyXSteps != 0)
+      m_counter = clamp<unsigned>(m_counter, 0, m_everyXSteps - 1);
+    else
+      m_counter = 0;
+  }
+
+  // Will the next tick() return true?
+  bool ready() const {
+    return m_everyXSteps != 0 && m_counter == 0;
+  }
+
+  bool tick() {
+    if (m_everyXSteps == 0)
+      return false;
+
+    if (m_counter == 0) {
+      m_counter = m_everyXSteps - 1;
+      return true;
+    } else {
+      --m_counter;
+      return false;
+    }
+  }
+
+  template <typename Function>
+  void tick(Function&& function) {
+    if (tick())
+      function();
+  }
+
+private:
+  unsigned m_counter;
+  unsigned m_everyXSteps;
+};
+
+// Perform some action with a given period over an amount of some value (like
+// time) with optional randomness.
+class RatePeriodic {
+public:
+  RatePeriodic(double period = 1, double noise = 0)
+    : m_period(period), m_noise(noise), m_counter(period + Random::randf(-noise, noise)), m_elapsed(0.0) {}
+
+  double period() const {
+    return m_period;
+  }
+
+  double noise() const {
+    return m_noise;
+  }
+
+  template <typename Function>
+  void update(double amount, Function&& function) {
+    double subAmount = min(amount, m_counter);
+    m_counter -= subAmount;
+    amount -= subAmount;
+    m_elapsed += subAmount;
+
+    if (m_counter <= 0.0) {
+      m_counter = m_period + Random::randf(-m_noise, m_noise);
+      function(m_elapsed);
+      m_elapsed = 0.0;
+      if (amount > 0.0)
+        update(amount, forward<Function>(function));
+    }
+  }
+
+private:
+  double m_period;
+  double m_noise;
+  double m_counter;
+  double m_elapsed;
+};
+
+}
+
+#endif