5 files changed, 79 insertions, 5 deletions

diff --git a/include/ballistics.h b/include/ballistics.h
index ab68c3f..7ba4248 100644
--- a/include/ballistics.h
+++ b/include/ballistics.h
@@ -19,4 +19,21 @@ double retard(DragFunction drag_function,
 			  double velocity,
 			  double temperature);
 
+typedef struct RangeCardRecord RangeCardRecord;
+struct RangeCardRecord {
+	size_t n;
+	double range;
+	double elevation;
+	Windage windage;
+	double lead;
+	double time_of_flight;
+	double bullet_speed;
+	double kinetic_energy;
+};
+typedef struct RangeCard RangeCard;
+struct RangeCard {
+	RangeCardRecord *card;
+	size_t records;
+};
+
 #endif
diff --git a/include/constants.h b/include/constants.h
index 026ff7b..f367e4b 100644
--- a/include/constants.h
+++ b/include/constants.h
@@ -11,4 +11,8 @@ static const double STD_AIR_DENSITY_ICAO = 1.22498;
 static const double STD_AIR_DENSITY_ASM = 1.20886;
 static const double BC_CONVERSION_FACTOR = 0.00068418;
 
+static const double rangeCardStartRange = 200;
+static const double rangeCardIncrement = 50;
+static const double rangeCardEndRange = 2000;
+
 #endif
diff --git a/include/context.h b/include/context.h
index 5dfad31..dd207bb 100644
--- a/include/context.h
+++ b/include/context.h
@@ -21,6 +21,7 @@ typedef struct {
 	double ballistic_coef;
 	DragFunction drag_model;
 	double twist_dir;
+	double air_friction;
 } GunConfig;
 
 typedef struct {
diff --git a/include/misc.h b/include/misc.h
new file mode 100644
index 0000000..a0b235c
--- /dev/null
+++ b/include/misc.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdbool.h>
+
+#include "misc.h"
+#include "vector.h"
+
+#define MRAD_IN_DEG 17.45329252
+
+double linearConversion(double min_from,
+						double max_from,
+						double value,
+						double min_to,
+						double max_to,
+						bool clip);
+
+static inline double MRAD_TO_DEG(double d) {
+	return d / MRAD_IN_DEG;
+}
diff --git a/include/vector.h b/include/vector.h
index 72e6523..07d44cd 100644
--- a/include/vector.h
+++ b/include/vector.h
@@ -1,9 +1,42 @@
 #pragma once
-#include "vector.h"
+
+#include <math.h>
 
 typedef struct { double x, y, z; } Vec3;
 
-static inline double vec3_magnitude(Vec3 v);
-static inline Vec3 vec3_diff(Vec3 a, Vec3 b);
-static inline Vec3 vec3_normalize(Vec3 v);
-static inline Vec3 vec3_mul(Vec3 v, double n);
+static inline double vec3_magnitude(Vec3 v) {
+	return hypot(v.x, hypot(v.y, v.z));
+}
+
+static inline Vec3 vec3_diff(Vec3 a, Vec3 b) {
+	return (Vec3){.x = a.x - b.x,
+				  .y = a.y - b.y,
+				  .z = a.z - b.z};
+}
+
+static inline Vec3 vec3_normalize(Vec3 v) {
+	if (v.x == 0.0 || v.y == 0.0 || v.z == 0.0)
+		return (Vec3){.x = 0.0,
+					  .y = 0.0,
+					  .z = 0.0};
+
+	double len = sqrt(v.x * v.x
+					  + v.y * v.y
+					  + v.z * v.z);
+	return (Vec3){.x = v.x / len,
+				  .y = v.y / len,
+				  .z = v.z / len};
+}
+
+static inline Vec3 vec3_mul(Vec3 v, double n) {
+	return (Vec3) {.x = v.x * n,
+				   .y = v.y * n,
+				   .z = v.z * n};
+}
+
+static inline Vec3 vec3_add(Vec3 a, Vec3 b) {
+	return (Vec3) {.x = a.x + b.x,
+				   .y = a.y + b.y,
+				   .z = a.z + b.z};
+}
+