Fixed orbit

consts.h

@@ -1,9 +1,15 @@
 #ifndef CONSTS_H_
 #define CONSTS_H_
-#define TIMESTEP 10
-#define simx 2
+#define LOOP_TIMESTEP 1000000LL // Wall-clock nanoseconds between updates (1 kHz).
+#define PHYSICS_TIMESTEP 100.0f // Simulated seconds per update.
+#define WALL_COLLISIONS 0 // Enable for bounded collision tests.
 #define NEWTON_G 6.674e-11
+#define EARTH_MASS 5.9722e24 // Kilograms per simulation mass unit.
 #define UA 149.6E6
-#define RT 6378.14
+#define RT 6378.14 // Kilometers per simulation distance unit.
+#define DISTANCE_UNIT_METERS (RT * 1000.0)
+#define SIMULATION_G (NEWTON_G * EARTH_MASS / \
+                      (DISTANCE_UNIT_METERS * DISTANCE_UNIT_METERS * \
+                       DISTANCE_UNIT_METERS))
 
 #endif // CONSTS_H_