Factor out asteroid rotation code

Signed-off-by: Stephen M. Cameron <stephenmcameron@gmail.com>

Makefile

@@ -320,7 +320,7 @@ GLEWCFLAGS:=$(shell pkg-config --cflags glew)
 COMMONOBJS=mathutils.o snis_alloc.o snis_socket_io.o snis_marshal.o \
 		bline.o shield_strength.o stacktrace.o snis_ship_type.o \
 		snis_faction.o mtwist.o names.o infinite-taunt.o snis_damcon_systems.o \
-		string-utils.o c-is-the-locale.o starbase_metadata.o
+		string-utils.o c-is-the-locale.o starbase_metadata.o arbitrary_spin.o
 SERVEROBJS=${COMMONOBJS} snis_server.o starbase-comms.o \
 		power-model.o quat.o vec4.o matrix.o snis_event_callback.o space-part.o fleet.o \
 		commodities.o docking_port.o
@@ -676,6 +676,9 @@ quat.o:	quat.c Makefile
 vec4.o:	vec4.c Makefile
 	$(Q)$(COMPILE)
 
+arbitrary_spin.o:	arbitrary_spin.c arbitrary_spin.h Makefile
+	$(Q)$(COMPILE)
+
 mtwist.o:	mtwist.c Makefile
 	$(Q)$(COMPILE)
 

arbitrary_spin.c

@@ -0,0 +1,58 @@
+/*
+	Copyright (C) 2010 Stephen M. Cameron
+	Author: Stephen M. Cameron
+
+	This file is part of Spacenerds In Space.
+
+	Spacenerds in Space is free software; you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation; either version 2 of the License, or
+	(at your option) any later version.
+
+	Spacenerds in Space is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Spacenerds in Space; if not, write to the Free Software
+	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include "arbitrary_spin.h"
+
+void compute_arbitrary_spin(float frame_rate_hz, double timestamp,
+				union quat *orientation,
+				union quat *rotational_velocity)
+{
+	/* reduce to axis and angle */
+	float x, y, z, a;
+	quat_to_axis(rotational_velocity, &x, &y, &z, &a);
+
+	/* current rotation is universe timestamp * rotation per timestamp
+	   rotational_velocity is frame_rate_hz and universe is 1/10 sec */
+	a = a * frame_rate_hz / 10.0 * timestamp;
+
+	quat_init_axis(orientation, x, y, z, a);
+}
+
+union quat random_orientation[NRANDOM_ORIENTATIONS];
+union quat random_spin[NRANDOM_SPINS];
+
+void initialize_random_orientations_and_spins(int mtwist_seed)
+{
+	int i;
+	struct mtwist_state *mt;
+
+	mt = mtwist_init(mtwist_seed);
+	for (i = 0; i < NRANDOM_ORIENTATIONS; i++) {
+		float angle = mtwist_float(mt) * 2.0 * M_PI;
+		consistent_random_axis_quat(mt, &random_orientation[i], angle);
+	}
+	for (i = 0; i < NRANDOM_SPINS; i++) {
+		float angular_speed = ((float) mtwist_int(mt, 100) / 10.0 - 5.0) * M_PI / 180.0;
+		consistent_random_axis_quat(mt, &random_spin[i], angular_speed);
+	}
+	mtwist_free(mt);
+}
+

arbitrary_spin.h

@@ -0,0 +1,17 @@
+#ifndef ARBITRARY_SPIN_H__
+#define ARBITRARY_SPIN_H__
+
+#include <math.h>
+#include "quat.h"
+
+#define NRANDOM_ORIENTATIONS 20
+#define NRANDOM_SPINS 20
+extern union quat random_orientation[NRANDOM_ORIENTATIONS];
+extern union quat random_spin[NRANDOM_SPINS];
+extern void initialize_random_orientations_and_spins(int mtwist_seed);
+extern void compute_arbitrary_spin(float frame_rate_hz, double timestamp,
+					union quat *orientation,
+					union quat *rotational_velocity);
+
+#endif
+

snis_client.c

@@ -67,6 +67,7 @@
 #include "infinite-taunt.h"
 #include "mathutils.h"
 #include "quat.h"
+#include "arbitrary_spin.h"
 #include "snis.h"
 #include "snis-culture.h"
 #include "snis_alloc.h"
@@ -395,27 +396,6 @@ struct my_vect_obj placeholder_part_spun[128];
 static struct snis_entity *curr_science_guy = NULL;
 static struct snis_entity *prev_science_guy = NULL;
 
-#define NRANDOM_ORIENTATIONS 20
-static union quat random_orientation[NRANDOM_ORIENTATIONS];
-#define NRANDOM_SPINS 20
-static union quat random_spin[NRANDOM_SPINS];
-static void initialize_random_orientations_and_spins(void)
-{
-	int i;
-	struct mtwist_state *mt;
-
-	mt = mtwist_init(mtwist_seed);
-	for (i = 0; i < NRANDOM_ORIENTATIONS; i++) {
-		float angle = mtwist_float(mt) * 2.0 * M_PI;
-		consistent_random_axis_quat(mt, &random_orientation[i], angle);
-	}
-	for (i = 0; i < NRANDOM_SPINS; i++) {
-		float angular_speed = ((float) mtwist_int(mt, 100) / 10.0 - 5.0) * M_PI / 180.0;
-		consistent_random_axis_quat(mt, &random_spin[i], angular_speed);
-	}
-	mtwist_free(mt);
-}
-
 void to_snis_heading_mark(const union quat *q, double *heading, double *mark)
 {
 	quat_to_heading_mark(q,heading,mark);
@@ -1776,15 +1756,7 @@ static void spin_wormhole(double timestamp, struct snis_entity *o)
 
 static void arbitrary_spin(double timestamp, struct snis_entity *o, union quat *rotational_velocity)
 {
-	/* reduce to axis and angle */
-	float x, y, z, a;
-	quat_to_axis(rotational_velocity, &x, &y, &z, &a);
-
-	/* current rotation is universe timestamp * rotation per timestamp
-	   rotational_velocity is frame_rate_hz and universe is 1/10 sec */
-	a = a * (float)frame_rate_hz / 10.0 * timestamp;
-
-	quat_init_axis(&o->orientation, x, y, z, a);
+	compute_arbitrary_spin(frame_rate_hz, timestamp, &o->orientation, rotational_velocity);
 	if (o->entity)
 		update_entity_orientation(o->entity, &o->orientation);
 }
@@ -13528,7 +13500,7 @@ int main(int argc, char *argv[])
 	init_keymap();
 	read_keymap_config_file();
 	init_vects();
-	initialize_random_orientations_and_spins();
+	initialize_random_orientations_and_spins(COMMON_MTWIST_SEED);
 	if (read_planet_material_metadata(&nplanet_materials)) {
 		fprintf(stderr, "Failed reading planet material metadata\n");
 		exit(1);