Refactor: Move compass() and approximate_distance() from Lua to C

3 files changed, 93 insertions, 0 deletions

diff --git a/src/externs.h b/src/externs.h
index f5bb610c..dc01f361 100644
--- a/src/externs.h
+++ b/src/externs.h
@@ -1824,6 +1824,11 @@ extern void lua_delete_list(list_type *, int size);
 extern void lua_add_to_list(list_type *, int idx, cptr str);
 extern void lua_display_list(int y, int x, int h, int w, cptr title, list_type *list, int max, int begin, int sel, byte sel_color);
 
+extern cptr compass(int y, int x, int y2, int x2);
+extern cptr approximate_distance(int y, int x, int y2, int x2);
+
+extern cptr compass(int y, int x, int y2, int x2);
+extern cptr approximate_distance(int y, int x, int y2, int x2);
 
 /* skills.c */
 extern void dump_skills(FILE *fff);
diff --git a/src/lua_bind.c b/src/lua_bind.c
index 116147e9..7894b7d4 100644
--- a/src/lua_bind.c
+++ b/src/lua_bind.c
@@ -548,3 +548,85 @@ void desc_god(int g_idx, int d, char *desc)
 	if (d >= 0 && d < 10)
 		strncpy(deity_info[g_idx].desc[d], desc, 79);
 }
+
+/*
+ * Returns the direction of the compass that y2, x2 is from y, x
+ * the return value will be one of the following: north, south,
+ * east, west, north-east, south-east, south-west, north-west,
+ * or "close" if it is within 2 tiles.
+ */
+cptr compass(int y, int x, int y2, int x2)
+{
+	static char compass_dir[64];
+
+	// is it close to the north/south meridian?
+	int y_diff = y2 - y;
+
+	// determine if y2, x2 is to the north or south of y, x
+	const char *y_axis;
+	if ((y_diff > -3) && (y_diff < 3))
+	{
+		y_axis = 0;
+	}
+	else if (y2 > y)
+	{
+		y_axis = "south";
+	}
+	else
+	{
+		y_axis = "north";
+	}
+
+	// is it close to the east/west meridian?
+	int x_diff = x2 - x;
+
+	// determine if y2, x2 is to the east or west of y, x
+	const char *x_axis;
+	if ((x_diff > -3) && (x_diff < 3))
+	{
+		x_axis = 0;
+	}
+	else if (x2 > x)
+	{
+		x_axis = "east";
+	}
+	else
+	{
+		x_axis = "west";
+	}
+
+	// Maybe it is very close
+	if ((!x_axis) && (!y_axis)) { strcpy(compass_dir, "close"); }
+	// Maybe it is (almost) due N/S
+	else if (!x_axis) { strcpy(compass_dir, y_axis); }
+	// Maybe it is (almost) due E/W
+	else if (!y_axis) { strcpy(compass_dir, x_axis); }
+	//  or if it is neither
+	else { sprintf(compass_dir, "%s-%s", y_axis, x_axis); }
+	return compass_dir;
+}
+
+/* Returns a relative approximation of the 'distance' of y2, x2 from y, x. */
+cptr approximate_distance(int y, int x, int y2, int x2)
+{
+	//  how far to away to the north/south?
+	int y_diff = abs(y2 - y);
+	// how far to away to the east/west?
+	int x_diff = abs(x2 - x);
+	// find which one is the larger distance
+	int most_dist = x_diff;
+	if (y_diff > most_dist) {
+		most_dist = y_diff;
+	}
+
+	// how far away then?
+	if (most_dist >= 41) {
+		return "a very long way";
+	} else if (most_dist >= 25) {
+		return "a long way";
+	} else if (most_dist >= 8) {
+		return "quite some way";
+	} else {
+		return "not very far";
+	}
+}
diff --git a/src/util.pkg b/src/util.pkg
index b118f2b0..c6f97ebf 100644
--- a/src/util.pkg
+++ b/src/util.pkg
@@ -1514,6 +1514,12 @@ extern void quit(cptr str);
  */
 extern s32b value_scale(int value, int vmax, int max, int min);
 
+/*
+ * compass, approximate_distance
+ */
+extern cptr compass(int y, int x, int y2, int x2);
+extern cptr approximate_distance(int y, int x, int y2, int x2);
+
 /** @fn text_out_c(byte a, cptr str)
  * @brief Output text to the screen (in color) or to a file depending on the
  * selected hook.\n