rigidbody: Add force field support

Force fields work with rigid bodies just like they do with other simulations.

Increase min and max strength of force fields so they can influence heavy rigid
bodies.

TODO: Adjust force field strength based on the time step taken.

Part of GSoC 2010 and 2012.
Authors: Joshua Leung (aligorith), Sergej Reich (sergof)

1 files changed, 44 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/rigidbody.c b/source/blender/blenkernel/intern/rigidbody.c
index e6f6c9a9a98..90200fd6742 100644
--- a/source/blender/blenkernel/intern/rigidbody.c
+++ b/source/blender/blenkernel/intern/rigidbody.c
@@ -97,6 +97,10 @@ void BKE_rigidbody_free_world(RigidBodyWorld *rbw)
 	if (rbw->objects)
 		free(rbw->objects);
 
+	/* free effector weights */
+	if (rbw->effector_weights)
+		MEM_freeN(rbw->effector_weights);
+
 	/* free rigidbody world itself */
 	MEM_freeN(rbw);
 }
@@ -459,6 +463,8 @@ RigidBodyWorld *BKE_rigidbody_create_world(Scene *scene)
 	rbw = MEM_callocN(sizeof(RigidBodyWorld), "RigidBodyWorld");
 
 	/* set default settings */
+	rbw->effector_weights = BKE_add_effector_weights(NULL);
+
 	rbw->ltime = PSFRA;
 
 	rbw->time_scale = 1.0f;
@@ -596,6 +602,7 @@ static void rigidbody_update_sim_world(Scene *scene, RigidBodyWorld *rbw)
 	/* adjust gravity to take effector weights into account */
 	if (scene->physics_settings.flag & PHYS_GLOBAL_GRAVITY) {
 		copy_v3_v3(adj_gravity, scene->physics_settings.gravity);
+		mul_v3_fl(adj_gravity, rbw->effector_weights->global_gravity * rbw->effector_weights->weight[0]);
 	}
 	else {
 		zero_v3(adj_gravity);
@@ -631,6 +638,43 @@ static void rigidbody_update_sim_ob(Scene *scene, RigidBodyWorld *rbw, Object *o
 		RB_body_activate(rbo->physics_object);
 		RB_body_set_loc_rot(rbo->physics_object, loc, rot);
 	}
+	/* update influence of effectors - but don't do it on an effector */
+	/* only dynamic bodies need effector update */
+	else if (rbo->type == RBO_TYPE_ACTIVE && ((ob->pd == NULL) || (ob->pd->forcefield == PFIELD_NULL))) {
+		EffectorWeights *effector_weights = rbw->effector_weights;
+		EffectedPoint epoint;
+		ListBase *effectors;
+
+		/* get effectors present in the group specified by effector_weights */
+		effectors = pdInitEffectors(scene, ob, NULL, effector_weights);
+		if (effectors) {
+			float force[3] = {0.0f, 0.0f, 0.0f};
+			float loc[3], vel[3];
+
+			/* create dummy 'point' which represents last known position of object as result of sim */
+			// XXX: this can create some inaccuracies with sim position, but is probably better than using unsimulated vals?
+			RB_body_get_position(rbo->physics_object, loc);
+			RB_body_get_linear_velocity(rbo->physics_object, vel);
+
+			pd_point_from_loc(scene, loc, vel, 0, &epoint);
+
+			/* calculate net force of effectors, and apply to sim object
+			 *	- we use 'central force' since apply force requires a "relative position" which we don't have...
+			 */
+			pdDoEffectors(effectors, NULL, effector_weights, &epoint, force, NULL);
+			if (G.f & G_DEBUG)
+				printf("\tapplying force (%f,%f,%f) to '%s'\n", force[0], force[1], force[2], ob->id.name + 2);
+			/* activate object in case it is deactivated */
+			if (!is_zero_v3(force))
+				RB_body_activate(rbo->physics_object);
+			RB_body_apply_central_force(rbo->physics_object, force);
+		}
+		else if (G.f & G_DEBUG)
+			printf("\tno forces to apply to '%s'\n", ob->id.name + 2);
+
+		/* cleanup */
+		pdEndEffectors(&effectors);
+	}
 	/* NOTE: passive objects don't need to be updated since they don't move */
 
 	/* NOTE: no other settings need to be explicitly updated here,