[feature]: ADSR (#15)

closes #14

Reviewed-on: #15

src/Ramp.cpp

@@ -0,0 +1,27 @@
+#include "Ramp.h"
+#include "Logger.h"
+
+Ramp::Ramp(float starting_level, float sample_rate) {
+    m_level = starting_level;
+    m_sample_rate = sample_rate;
+}
+
+Ramp::~Ramp() {}
+
+void Ramp::RampTo(float val, float time) {
+    m_increment = (val - m_level) / (m_sample_rate * time);
+    m_counter = (int)(m_sample_rate * time);
+    write_log("Ramping from: %.1f to: %.1f by: %lf for: %d\n", m_level, val,
+              m_increment, m_counter);
+}
+
+float Ramp::Process() {
+    if (m_counter > 0) {
+        m_counter--;
+        m_level += m_increment;
+    }
+
+    return m_level;
+}
+
+bool Ramp::IsCompleted() { return m_counter == 0; }