5 files changed, 37 insertions, 13 deletions
diff --git a/include/ballistics.h b/include/ballistics.h
index 84a883d..ab68c3f 100644
--- a/include/ballistics.h
+++ b/include/ballistics.h
@@ -2,6 +2,7 @@
 #define ACE_BALLISTICS_H
 
 #include "context.h"
+#include "drag_model.h"
 
 double atmospheric_correction(double ballistic_coefficient,
                               double temperature,
@@ -13,7 +14,7 @@ double calculate_air_density(double temperature,
 							 double pressure,
 							 double relative_humidity);
 
-double retard(DragModel ballistic_model,
+double retard(DragFunction drag_function,
 			  double ballistic_coefficient,
 			  double velocity,
 			  double temperature);
diff --git a/include/constants.h b/include/constants.h
index cfc9c80..026ff7b 100644
--- a/include/constants.h
+++ b/include/constants.h
@@ -9,5 +9,6 @@ static const double UNIVERSAL_GAS_CONSTANT = 8.31432;
 static const double SPECIFIC_GAST_CONSTANT_DRY_AIR = 287.057036320950;
 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;
 
 #endif
diff --git a/include/context.h b/include/context.h
index 65b4585..5dfad31 100644
--- a/include/context.h
+++ b/include/context.h
@@ -6,17 +6,7 @@
 #include <stdbool.h>
 
 #include "ace.h"
-
-typedef enum {
-	BC_UNKNOWN = 0,
-	BC_G1,
-	BC_G2,
-	BC_G3,
-	BC_G4,
-	BC_G5,
-	BC_G6,
-	BC_G7,
-} DragModel;
+#include "drag_model.h"
 
 typedef enum {
 	ICAO,
@@ -29,7 +19,7 @@ typedef struct {
 	double bore_height;
 	double muzzle_velocity;
 	double ballistic_coef;
-	size_t drag_model;
+	DragFunction drag_model;
 	double twist_dir;
 } GunConfig;
 
diff --git a/include/drag_model.h b/include/drag_model.h
index baf5f72..8c18bed 100644
--- a/include/drag_model.h
+++ b/include/drag_model.h
@@ -1,6 +1,29 @@
 #ifndef DRAG_MODEL_H
 #define DRAG_MODEL_H
 
+#include <stddef.h>
 
+typedef enum {
+	DRAG_G1,
+	DRAG_G2,
+	DRAG_G5,
+	DRAG_G6,
+	DRAG_G7,
+	DRAG_G8,
+	DRAG_COUNT
+} DragFunction;
+
+typedef struct {
+	size_t num_points;
+	const double *mach;
+	const double *cd;
+} DragModel;
+
+extern const DragModel drag_models[DRAG_COUNT];
+
+static inline const DragModel* get_drag_model(DragFunction func) {
+	if (func >= DRAG_COUNT) return NULL;
+	return &drag_models[func];
+}
 
 #endif
diff --git a/include/vector.h b/include/vector.h
new file mode 100644
index 0000000..5b0d2de
--- /dev/null
+++ b/include/vector.h
@@ -0,0 +1,9 @@
+#pragma once
+#include "vector.h"
+#include <stdlib.h>
+
+typedef struct vector_t vector_t;
+
+vector_t* vector_new(void);
+void vector_ctr(vector_t* obj);
+void vector_dtr(vector_t* obj);