1 files changed, 32 insertions, 0 deletions
diff --git a/common/accel-naturalgain.hpp b/common/accel-naturalgain.hpp
new file mode 100644
index 0000000..95c0be2
--- /dev/null
+++ b/common/accel-naturalgain.hpp
@@ -0,0 +1,32 @@
+#pragma once
+
+#include <math.h>
+
+#include "accel-base.hpp"
+
+namespace rawaccel {
+
+	/// <summary> Struct to hold "natural" (vanishing difference) gain implementation. </summary>
+	struct accel_naturalgain : accel_base {
+		double limit = 1;
+		double midpoint = 0;
+
+		accel_naturalgain(const accel_args& args) : accel_base(args) {
+			verify(args);
+
+			limit = args.limit - 1;
+			speed_coeff /= limit;
+		}
+
+		inline double accelerate(double speed) const {
+			// f(x) = k((e^(-mx)-1)/mx + 1)
+			double scaled_speed = speed_coeff * speed;
+			return limit * (((exp(-scaled_speed) - 1) / scaled_speed) + 1);
+		}
+
+		void verify(const accel_args& args) const {
+			if (args.limit <= 1) bad_arg("limit must be greater than 1");
+		}
+	};
+
+}