add tweaks for st-refactor

1 files changed, 31 insertions, 0 deletions

diff --git a/common/accel-natural.hpp b/common/accel-natural.hpp
new file mode 100644
index 0000000..6ccb193
--- /dev/null
+++ b/common/accel-natural.hpp
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <math.h>
+
+#include "accel-base.hpp"
+
+namespace rawaccel {
+
+	/// <summary> Struct to hold "natural" (vanishing difference) acceleration implementation. </summary>
+	struct accel_natural : accel_base {
+		double limit = 1;
+		double midpoint = 0;
+
+		accel_natural(accel_args args) : accel_base(args) {
+			verify(args);
+
+			limit = args.limit - 1;
+			speed_coeff /= limit;
+		}
+
+		inline double accelerate(double speed) const {
+			// f(x) = k(1-e^(-mx))
+			return limit - (limit * exp(-speed_coeff * speed));
+		}
+
+		void verify(accel_args args) const {
+			if (args.limit <= 1) error("limit must be greater than 1");
+		}
+	};
+
+}