Cloth: Improve UI

This reorganizes the cloth UI, and changes some of the behaviour to be
more reasonable.

Changes included here:
* Reorganized cloth panels
* Improved some tooltips
* Removed `vel_damping` option
* Removed cloth pinning checkbox
* Removed stiffness scaling checkbox
* Separated shrinking from sewing
* Separated self collisions from object collisions

Reviewed By: brecht

Differential Revision: http://developer.blender.org/D3691

3 files changed, 102 insertions, 105 deletions

diff --git a/source/blender/blenkernel/intern/cloth.c b/source/blender/blenkernel/intern/cloth.c
index 53894431fc3..a0475e98037 100644
--- a/source/blender/blenkernel/intern/cloth.c
+++ b/source/blender/blenkernel/intern/cloth.c
@@ -117,7 +117,6 @@ void cloth_init(ClothModifierData *clmd )
 	clmd->sim_parms->timescale = 1.0f; /* speed factor, describes how fast cloth moves */
 	clmd->sim_parms->time_scale = 1.0f; /* multiplies cloth speed */
 	clmd->sim_parms->reset = 0;
-	clmd->sim_parms->vel_damping = 1.0f; /* 1.0 = no damping, 0.0 = fully dampened */
 
 	clmd->coll_parms->self_friction = 5.0;
 	clmd->coll_parms->friction = 5.0;
@@ -396,8 +395,11 @@ static int do_step_cloth(Depsgraph *depsgraph, Object *ob, ClothModifierData *cl
 	/* Support for dynamic vertex groups, changing from frame to frame */
 	cloth_apply_vgroup ( clmd, result );
 
-	if ( clmd->sim_parms->flags & (CLOTH_SIMSETTINGS_FLAG_SEW | CLOTH_SIMSETTINGS_FLAG_DYNAMIC_BASEMESH) )
+	if ((clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_DYNAMIC_BASEMESH) ||
+	    (clmd->sim_parms->vgroup_shrink > 0) || (clmd->sim_parms->shrink_min > 0.0f))
+	{
 		cloth_update_spring_lengths ( clmd, result );
+	}
 
 	cloth_update_springs( clmd );
 
@@ -679,15 +681,11 @@ static void cloth_to_object (Object *ob,  ClothModifierData *clmd, float (*verte
 
 int cloth_uses_vgroup(ClothModifierData *clmd)
 {
-	return (((clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_SCALING ) ||
-		(clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_GOAL ) ||
-		(clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_SEW) ||
-		(clmd->coll_parms->flags & CLOTH_COLLSETTINGS_FLAG_SELF)) &&
-		((clmd->sim_parms->vgroup_mass>0) ||
-		(clmd->sim_parms->vgroup_struct>0)||
-		(clmd->sim_parms->vgroup_bend>0)  ||
-		(clmd->sim_parms->vgroup_shrink>0) ||
-		(clmd->coll_parms->vgroup_selfcol>0)));
+	return (((clmd->coll_parms->flags & CLOTH_COLLSETTINGS_FLAG_SELF) && (clmd->coll_parms->vgroup_selfcol > 0)) ||
+	        (clmd->sim_parms->vgroup_struct > 0) ||
+	        (clmd->sim_parms->vgroup_bend > 0) ||
+	        (clmd->sim_parms->vgroup_shrink > 0) ||
+	        (clmd->sim_parms->vgroup_mass > 0));
 }
 
 /**
@@ -717,7 +715,7 @@ static void cloth_apply_vgroup ( ClothModifierData *clmd, Mesh *mesh )
 		for (i = 0; i < mvert_num; i++, verts++) {
 
 			/* Reset Goal values to standard */
-			if ( clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_GOAL )
+			if (clmd->sim_parms->vgroup_mass > 0)
 				verts->goal= clmd->sim_parms->defgoal;
 			else
 				verts->goal= 0.0f;
@@ -732,7 +730,7 @@ static void cloth_apply_vgroup ( ClothModifierData *clmd, Mesh *mesh )
 			dvert = CustomData_get(&mesh->vdata, i, CD_MDEFORMVERT);
 			if ( dvert ) {
 				for ( j = 0; j < dvert->totweight; j++ ) {
-					if (( dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_mass-1)) && (clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_GOAL )) {
+					if (dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_mass - 1)) {
 						verts->goal = dvert->dw [j].weight;
 
 						/* goalfac= 1.0f; */ /* UNUSED */
@@ -745,18 +743,16 @@ static void cloth_apply_vgroup ( ClothModifierData *clmd, Mesh *mesh )
 							verts->flags |= CLOTH_VERT_FLAG_PINNED;
 					}
 
-					if (clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_SCALING ) {
-						if ( dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_struct-1)) {
-							verts->struct_stiff = dvert->dw [j].weight;
-						}
+					if (dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_struct - 1)) {
+						verts->struct_stiff = dvert->dw[j].weight;
+					}
 
-						if ( dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_shear-1)) {
-							verts->shear_stiff = dvert->dw [j].weight;
-						}
+					if (dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_shear - 1)) {
+						verts->shear_stiff = dvert->dw[j].weight;
+					}
 
-						if ( dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_bend-1)) {
-							verts->bend_stiff = dvert->dw [j].weight;
-						}
+					if (dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_bend - 1)) {
+						verts->bend_stiff = dvert->dw[j].weight;
 					}
 
 					if (clmd->coll_parms->flags & CLOTH_COLLSETTINGS_FLAG_SELF ) {
@@ -766,12 +762,10 @@ static void cloth_apply_vgroup ( ClothModifierData *clmd, Mesh *mesh )
 							}
 						}
 					}
-					if ( clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_SEW ) {
-						if (clmd->sim_parms->vgroup_shrink > 0) {
-							if (dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_shrink - 1)) {
-								/* used for linear interpolation between min and max shrink factor based on weight */
-								verts->shrink_factor = dvert->dw[j].weight;
-							}
+					if (clmd->sim_parms->vgroup_shrink > 0) {
+						if (dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_shrink - 1)) {
+							/* Used for linear interpolation between min and max shrink factor based on weight. */
+							verts->shrink_factor = dvert->dw[j].weight;
 						}
 					}
 				}
@@ -782,20 +776,16 @@ static void cloth_apply_vgroup ( ClothModifierData *clmd, Mesh *mesh )
 
 static float cloth_shrink_factor(ClothModifierData *clmd, ClothVertex *verts, int i1, int i2)
 {
-	if ( clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_SEW ) {
-		/* linear interpolation between min and max shrink factor based on weight */
-		float base = 1.0f - clmd->sim_parms->shrink_min;
-		float delta = clmd->sim_parms->shrink_min - clmd->sim_parms->shrink_max;
+	/* Linear interpolation between min and max shrink factor based on weight. */
+	float base = 1.0f - clmd->sim_parms->shrink_min;
+	float delta = clmd->sim_parms->shrink_min - clmd->sim_parms->shrink_max;
 
-		float k1 = base + delta * verts[i1].shrink_factor;
-		float k2 = base + delta * verts[i2].shrink_factor;
+	float k1 = base + delta * verts[i1].shrink_factor;
+	float k2 = base + delta * verts[i2].shrink_factor;
 
-		/* Use geometrical mean to average two factors since it behaves better
-		   for diagonals when a rectangle transforms into a trapezoid. */
-		return sqrtf(k1 * k2);
-	}
-	else
-		return 1.0f;
+	/* Use geometrical mean to average two factors since it behaves better
+	   for diagonals when a rectangle transforms into a trapezoid. */
+	return sqrtf(k1 * k2);
 }
 
 static int cloth_from_object(Object *ob, ClothModifierData *clmd, Mesh *mesh, float UNUSED(framenr), int first)
@@ -864,7 +854,7 @@ static int cloth_from_object(Object *ob, ClothModifierData *clmd, Mesh *mesh, fl
 		verts->mass = clmd->sim_parms->mass;
 		verts->impulse_count = 0;
 
-		if ( clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_GOAL )
+		if (clmd->sim_parms->vgroup_mass > 0)
 			verts->goal= clmd->sim_parms->defgoal;
 		else
 			verts->goal= 0.0f;
diff --git a/source/blender/blenkernel/intern/collision.c b/source/blender/blenkernel/intern/collision.c
index d7fab317105..183a4f9a181 100644
--- a/source/blender/blenkernel/intern/collision.c
+++ b/source/blender/blenkernel/intern/collision.c
@@ -708,88 +708,96 @@ int cloth_bvh_objcollision(Depsgraph *depsgraph, Object *ob, ClothModifierData *
 	// static collisions
 	////////////////////////////////////////////////////////////
 
-	// update cloth bvh
-	bvhtree_update_from_cloth ( clmd, 1 ); // 0 means STATIC, 1 means MOVING (see later in this function)
-	bvhselftree_update_from_cloth ( clmd, 0 ); // 0 means STATIC, 1 means MOVING (see later in this function)
+	if (clmd->coll_parms->flags & CLOTH_COLLSETTINGS_FLAG_ENABLED) {
+		bvhtree_update_from_cloth(clmd, true);
 
-	collobjs = BKE_collision_objects_create(depsgraph, ob, clmd->coll_parms->group, &numcollobj, eModifierType_Collision);
+		collobjs = BKE_collision_objects_create(depsgraph, ob, clmd->coll_parms->group, &numcollobj, eModifierType_Collision);
 
-	if (!collobjs)
-		return 0;
+		if (!collobjs) {
+			return 0;
+		}
 
-	/* move object to position (step) in time */
-	for (i = 0; i < numcollobj; i++) {
-		Object *collob= collobjs[i];
-		CollisionModifierData *collmd = (CollisionModifierData *)modifiers_findByType(collob, eModifierType_Collision);
+		/* Move object to position (step) in time. */
+		for (i = 0; i < numcollobj; i++) {
+			Object *collob = collobjs[i];
+			CollisionModifierData *collmd = (CollisionModifierData *)modifiers_findByType(collob, eModifierType_Collision);
 
-		if (!collmd->bvhtree)
-			continue;
+			if (!collmd->bvhtree) {
+				continue;
+			}
 
-		/* move object to position (step) in time */
-		collision_move_object ( collmd, step + dt, step );
+			/* Move object to position (step) in time. */
+			collision_move_object(collmd, step + dt, step);
+		}
 	}
 
-	do {
-		CollPair **collisions, **collisions_index;
+	if (clmd->coll_parms->flags & CLOTH_COLLSETTINGS_FLAG_SELF) {
+		bvhselftree_update_from_cloth(clmd, false);
+	}
 
+	do {
 		ret2 = 0;
 
-		collisions = MEM_callocN(sizeof(CollPair *) *numcollobj, "CollPair");
-		collisions_index = MEM_callocN(sizeof(CollPair *) *numcollobj, "CollPair");
+		if (clmd->coll_parms->flags & CLOTH_COLLSETTINGS_FLAG_ENABLED) {
+			CollPair **collisions, **collisions_index;
 
-		// check all collision objects
-		for (i = 0; i < numcollobj; i++) {
-			Object *collob= collobjs[i];
-			CollisionModifierData *collmd = (CollisionModifierData *)modifiers_findByType(collob, eModifierType_Collision);
-			BVHTreeOverlap *overlap = NULL;
-			unsigned int result = 0;
+			collisions = MEM_callocN(sizeof(CollPair *) *numcollobj, "CollPair");
+			collisions_index = MEM_callocN(sizeof(CollPair *) *numcollobj, "CollPair");
 
-			if (!collmd->bvhtree)
-				continue;
+			/* Check all collision objects. */
+			for (i = 0; i < numcollobj; i++) {
+				Object *collob= collobjs[i];
+				CollisionModifierData *collmd = (CollisionModifierData *)modifiers_findByType(collob, eModifierType_Collision);
+				BVHTreeOverlap *overlap = NULL;
+				unsigned int result = 0;
 
-			/* search for overlapping collision pairs */
-			overlap = BLI_bvhtree_overlap(cloth_bvh, collmd->bvhtree, &result, NULL, NULL);
+				if (!collmd->bvhtree) {
+					continue;
+				}
 
-			// go to next object if no overlap is there
-			if ( result && overlap ) {
-				/* check if collisions really happen (costly near check) */
-				cloth_bvh_objcollisions_nearcheck ( clmd, collmd, &collisions[i],
-					&collisions_index[i], result, overlap, dt/(float)clmd->coll_parms->loop_count);
+				/* Search for overlapping collision pairs. */
+				overlap = BLI_bvhtree_overlap(cloth_bvh, collmd->bvhtree, &result, NULL, NULL);
 
-				// resolve nearby collisions
-				ret += cloth_bvh_objcollisions_resolve ( clmd, collmd, collisions[i],  collisions_index[i]);
-				ret2 += ret;
-			}
+				/* Go to next object if no overlap is there. */
+				if (result && overlap) {
+					/* Check if collisions really happen (costly near check). */
+					cloth_bvh_objcollisions_nearcheck(clmd, collmd, &collisions[i], &collisions_index[i],
+					                                  result, overlap, dt/(float)clmd->coll_parms->loop_count);
 
-			if ( overlap )
-				MEM_freeN ( overlap );
-		}
-		rounds++;
+					/* Resolve nearby collisions. */
+					ret += cloth_bvh_objcollisions_resolve(clmd, collmd, collisions[i], collisions_index[i]);
+					ret2 += ret;
+				}
 
-		for (i = 0; i < numcollobj; i++) {
-			if ( collisions[i] ) MEM_freeN ( collisions[i] );
-		}
+				MEM_SAFE_FREE(overlap);
+			}
 
-		MEM_freeN(collisions);
-		MEM_freeN(collisions_index);
+			for (i = 0; i < numcollobj; i++) {
+				MEM_SAFE_FREE(collisions[i]);
+			}
 
-		////////////////////////////////////////////////////////////
-		// update positions
-		// this is needed for bvh_calc_DOP_hull_moving() [kdop.c]
-		////////////////////////////////////////////////////////////
+			MEM_freeN(collisions);
+			MEM_freeN(collisions_index);
 
-		/* verts come from clmd */
-		for (i = 0; i < mvert_num; i++) {
-			if ( clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_GOAL ) {
-				if ( verts [i].flags & CLOTH_VERT_FLAG_PINNED ) {
-					continue;
+			////////////////////////////////////////////////////////////
+			// update positions
+			// this is needed for bvh_calc_DOP_hull_moving() [kdop.c]
+			////////////////////////////////////////////////////////////
+
+			/* Verts come from clmd. */
+			for (i = 0; i < mvert_num; i++) {
+				if (clmd->sim_parms->vgroup_mass > 0) {
+					if (verts [i].flags & CLOTH_VERT_FLAG_PINNED) {
+						continue;
+					}
 				}
-			}
 
-			VECADD ( verts[i].tx, verts[i].txold, verts[i].tv );
+				VECADD(verts[i].tx, verts[i].txold, verts[i].tv);
+			}
+			////////////////////////////////////////////////////////////
 		}
-		////////////////////////////////////////////////////////////
 
+		rounds++;
 
 		////////////////////////////////////////////////////////////
 		// Test on *simple* selfcollisions
@@ -823,7 +831,7 @@ int cloth_bvh_objcollision(Depsgraph *depsgraph, Object *ob, ClothModifierData *
 
 						mindistance = clmd->coll_parms->selfepsilon* ( cloth->verts[i].avg_spring_len + cloth->verts[j].avg_spring_len );
 
-						if ( clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_GOAL ) {
+						if (clmd->sim_parms->vgroup_mass > 0) {
 							if ( ( cloth->verts [i].flags & CLOTH_VERT_FLAG_PINNED ) &&
 							     ( cloth->verts [j].flags & CLOTH_VERT_FLAG_PINNED ) )
 							{
@@ -1308,7 +1316,7 @@ int cloth_points_objcollision(Depsgraph *depsgraph, Object *ob, ClothModifierDat
 
 		// verts come from clmd
 		for (i = 0; i < mvert_num; i++) {
-			if ( clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_GOAL ) {
+			if (clmd->sim_parms->vgroup_mass > 0) {
 				if ( verts [i].flags & CLOTH_VERT_FLAG_PINNED ) {
 					continue;
 				}
@@ -1431,7 +1439,7 @@ void cloth_find_point_contacts(Depsgraph *depsgraph, Object *ob, ClothModifierDa
 
 	// verts come from clmd
 	for (i = 0; i < mvert_num; i++) {
-		if (clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_GOAL) {
+		if (clmd->sim_parms->vgroup_mass > 0) {
 			if (verts [i].flags & CLOTH_VERT_FLAG_PINNED) {
 				continue;
 			}
diff --git a/source/blender/blenkernel/intern/particle_system.c b/source/blender/blenkernel/intern/particle_system.c
index a5ce7893d3e..2179b035758 100644
--- a/source/blender/blenkernel/intern/particle_system.c
+++ b/source/blender/blenkernel/intern/particle_system.c
@@ -3170,8 +3170,7 @@ static void do_hair_dynamics(ParticleSimulationData *sim)
 	if (!psys->clmd) {
 		psys->clmd = (ClothModifierData*)modifier_new(eModifierType_Cloth);
 		psys->clmd->sim_parms->goalspring = 0.0f;
-		psys->clmd->sim_parms->vel_damping = 1.0f;
-		psys->clmd->sim_parms->flags |= CLOTH_SIMSETTINGS_FLAG_GOAL|CLOTH_SIMSETTINGS_FLAG_RESIST_SPRING_COMPRESS;
+		psys->clmd->sim_parms->flags |= CLOTH_SIMSETTINGS_FLAG_RESIST_SPRING_COMPRESS;
 		psys->clmd->coll_parms->flags &= ~CLOTH_COLLSETTINGS_FLAG_SELF;
 	}