1 files changed, 32 insertions, 0 deletions
diff --git a/common/accel-sigmoid.hpp b/common/accel-sigmoid.hpp
new file mode 100644
index 0000000..7cfa6c4
--- /dev/null
+++ b/common/accel-sigmoid.hpp
@@ -0,0 +1,32 @@
+#pragma once
+
+#include <math.h>
+
+#include "accel-base.hpp"
+
+namespace rawaccel {
+
+	/// <summary> Struct to hold sigmoid (s-shaped) acceleration implementation. </summary>
+	struct accel_sigmoid : accel_base {
+		double limit = 1;
+		double midpoint = 0;
+
+		accel_sigmoid(const accel_args& args) : accel_base(args) {
+			verify(args);
+
+			limit = args.limit - 1;
+			midpoint = args.midpoint;
+		}
+
+		inline double accelerate(double speed) const {
+			//f(x) = k/(1+e^(-m(c-x)))
+			return limit / (exp(-speed_coeff * (speed - midpoint)) + 1);
+		}
+
+		void verify(const accel_args& args) const {
+			if (args.limit <= 1) error("exponent must be greater than 1");
+			if (args.midpoint < 0) error("midpoint must not be negative");
+		}
+	};
+
+}