Add arbitrary lut struct

1 files changed, 103 insertions, 0 deletions

diff --git a/common/accel-lookup.hpp b/common/accel-lookup.hpp
index 18c9ea5..6c73605 100644
--- a/common/accel-lookup.hpp
+++ b/common/accel-lookup.hpp
@@ -149,4 +149,107 @@ namespace rawaccel {
 			binlog_lut(args.lut_args) {}
 	};
 
+	struct si_pair { 
+		double slope = 0;
+		double intercept = 0; 
+	};
+
+	struct arbitrary_lut_point {
+		double applicable_speed = 0;
+		si_pair slope_intercept = {};
+	};
+
+	struct arbitrary_lut {
+		fp_rep_range range;
+		arbitrary_lut_point data[LUT_CAPACITY] = {};
+		int log_lookup[LUT_CAPACITY] = {};
+		double first_point_speed;
+		double last_point_speed;
+		int last_index;
+
+		double operator()(double speed) const
+		{
+			int index = 0;
+
+			if (speed < first_point_speed)
+			{
+				// Apply from 0 index
+			}
+			else if (speed > last_point_speed)
+			{
+				index = last_index;
+			}
+			else if (speed > range.stop)
+			{
+				index = search_from(log_lookup[LUT_CAPACITY - 1], speed);
+			}
+			else if (speed < range.start)
+			{
+				index = search_from(0, speed);
+			}
+			else
+			{
+				int log_lookup = get_log_index(speed);
+				index = search_from(log_lookup, speed);
+			}
+
+			return apply(index, speed);
+		}
+
+		int inline get_log_index(double speed) const
+		{
+			double speed_log = log(speed) - range.start;
+			int index = (int)floor(speed_log * range.num);
+			return index;
+		}
+
+		int inline search_from(int index, double speed) const
+		{
+			int prev_index;
+
+			do
+			{
+				prev_index = index;
+				index++;
+			}
+			while (index <= last_index && data[index].applicable_speed < speed);
+
+			index--;
+		}
+
+		double inline apply(int index, double speed) const
+		{
+			si_pair pair = data[index].slope_intercept;
+			return pair.slope + pair.intercept / speed;
+		}
+
+		void fill(vec2d* points, int length) const
+		{
+			vec2d current = {0, 0};
+			vec2d next;
+			int log_index = 0;
+			double log_inner_iterator = range.start;
+			double log_inner_slice = 1 / range.num;
+			double log_value = pow(2, log_inner_iterator);
+
+			for (int i = 0; i < length; i++)
+			{
+				next = points[i];
+				double slope = (next.y - current.y) / (next.x - current.x);
+				double intercept = next.y - slope * next.x;
+				si_pair current_si = { slope, intercept };
+				arbitrary_lut_point current_lut_point = { next.x, current_si };
+
+				this->data[i] = current_lut_point;
+
+				while (log_value < next.x)
+				{
+					this->log_lookup[log_index] = log_value;
+					log_index++;
+					log_inner_iterator += log_inner_slice;
+					log_value = pow(2, log_inner_iterator);
+				}
+			}
+		}
+	};
 }