BGE: Adding support for Bullet's collision masks. Each object now has a collision mask and a collision group. Object A and object B collide if object A's groups is in object B's mask and object B's group is in object A's mask. In other words, the group defines what the object is (collision wise) and the group defines what the object can collide with.

The majority of this patch was provided by Kupoman with some edits from me and heavy testing by z0r.

release/scripts/startup/bl_ui/properties_game.py

@@ -190,6 +190,14 @@ class PHYSICS_PT_game_physics(PhysicsButtonsPanel, Panel):
             layout.operator("mesh.navmesh_reset")
             layout.operator("mesh.navmesh_clear")
 
+        if physics_type not in {'NO_COLLISION', 'OCCLUDE'}:
+            layout.separator()
+            split = layout.split()
+
+            col = split.column()
+            col.prop(game, "collision_group")
+            col = split.column()
+            col.prop(game, "collision_mask")
 
 class PHYSICS_PT_game_collision_bounds(PhysicsButtonsPanel, Panel):
     bl_label = "Collision Bounds"

source/blender/blenkernel/intern/object.c

@@ -854,7 +854,9 @@ Object *BKE_object_add_only_object(int type, const char *name)
 	ob->step_height = 0.15f;
 	ob->jump_speed = 10.0f;
 	ob->fall_speed = 55.0f;
-	
+	ob->col_group = 0x01;
+	ob->col_mask = 0xff;
+
 	/* NT fluid sim defaults */
 	ob->fluidsimSettings = NULL;
 

source/blender/blenloader/intern/readfile.c

@@ -8247,6 +8247,16 @@ static void do_versions(FileData *fd, Library *lib, Main *main)
 		
 	}
 
+	{
+		Object *ob;
+		for (ob = main->object.first; ob; ob = ob->id.next) {
+			if (ob->col_group == 0) {
+				ob->col_group = 0x01;
+				ob->col_mask = 0xff;
+			}
+		}
+	}
+
 	/* WATCH IT!!!: pointers from libdata have not been converted yet here! */
 	/* WATCH IT 2!: Userdef struct init has to be in editors/interface/resources.c! */
 

source/blender/makesdna/DNA_object_types.h

@@ -243,6 +243,9 @@ typedef struct Object {
 	short recalc;			/* dependency flag */
 	float anisotropicFriction[3];
 
+	/** Collision mask settings */
+	unsigned short col_group, col_mask, col_pad[2];
+
 	ListBase constraints;		/* object constraints */
 	ListBase nlastrips  DNA_DEPRECATED;			// XXX deprecated... old animation system
 	ListBase hooks  DNA_DEPRECATED;				// XXX deprecated... old animation system
@@ -479,6 +482,9 @@ typedef struct DupliObject {
 /* controller state */
 #define OB_MAX_STATES		30
 
+/* collision masks */
+#define OB_MAX_COL_MASKS	8
+
 /* ob->gameflag */
 #define OB_DYNAMIC		1
 #define OB_CHILD		2

source/blender/makesrna/intern/rna_object.c

@@ -1111,6 +1111,63 @@ static void rna_GameObjectSettings_used_state_get(PointerRNA *ptr, int *values)
 	}
 }
 
+static void rna_GameObjectSettings_col_group_get(PointerRNA *ptr, int *values)
+{
+	Object *ob = (Object*)ptr->data;
+	int i;
+
+	for (i = 0; i < OB_MAX_COL_MASKS; i++)
+		values[i] = (ob->col_group & (1<<i));
+}
+
+static void rna_GameObjectSettings_col_group_set(PointerRNA *ptr, const int *values)
+{
+	Object *ob = (Object*)ptr->data;
+	int i, tot = 0;
+
+	/* ensure we always have some group selected */
+	for (i = 0; i < OB_MAX_COL_MASKS; i++)
+		if(values[i])
+			tot++;
+
+	if (tot==0)
+		return;
+
+	for (i = 0; i < OB_MAX_COL_MASKS; i++) {
+		if (values[i]) ob->col_group |= (1<<i);
+		else ob->col_group &= ~(1<<i);
+	}
+}
+
+static void rna_GameObjectSettings_col_mask_get(PointerRNA *ptr, int *values)
+{
+	Object *ob = (Object*)ptr->data;
+	int i;
+
+	for (i = 0; i < OB_MAX_COL_MASKS; i++)
+		values[i] = (ob->col_mask & (1<<i));
+}
+
+static void rna_GameObjectSettings_col_mask_set(PointerRNA *ptr, const int *values)
+{
+	Object *ob = (Object*)ptr->data;
+	int i, tot = 0;
+
+	/* ensure we always have some mask selected */
+	for (i = 0; i < OB_MAX_COL_MASKS; i++)
+		if(values[i])
+			tot++;
+
+	if (tot==0)
+		return;
+
+	for (i = 0; i < OB_MAX_COL_MASKS; i++) {
+		if (values[i]) ob->col_mask |= (1<<i);
+		else ob->col_mask &= ~(1<<i);
+	}
+}
+
+
 static void rna_Object_active_shape_key_index_range(PointerRNA *ptr, int *min, int *max, int *softmin, int *softmax)
 {
 	Object *ob = (Object *)ptr->id.data;
@@ -1456,6 +1513,8 @@ static void rna_def_object_game_settings(BlenderRNA *brna)
 	StructRNA *srna;
 	PropertyRNA *prop;
 
+	int default_col_mask[8] = {1,0,0,0,  0,0,0,0};
+
 	static EnumPropertyItem body_type_items[] = {
 		{OB_BODY_TYPE_NO_COLLISION, "NO_COLLISION", 0, "No Collision", "Disable collision for this object"},
 		{OB_BODY_TYPE_STATIC, "STATIC", 0, "Static", "Stationary object"},
@@ -1578,6 +1637,17 @@ static void rna_def_object_game_settings(BlenderRNA *brna)
 	RNA_def_property_range(prop, 0.0, 1000.0);
 	RNA_def_property_ui_text(prop, "Fall Speed Max", "Maximum speed at which the character will fall");
 
+	prop = RNA_def_property(srna, "collision_group", PROP_BOOLEAN, PROP_LAYER_MEMBER);
+	RNA_def_property_boolean_sdna(prop, NULL, "col_group", 1);
+	RNA_def_property_array(prop, OB_MAX_COL_MASKS);
+	RNA_def_property_ui_text(prop, "Collision Group", "The collision group of the object");
+	RNA_def_property_boolean_funcs(prop, "rna_GameObjectSettings_col_group_get", "rna_GameObjectSettings_col_group_set");
+
+	prop = RNA_def_property(srna, "collision_mask", PROP_BOOLEAN, PROP_LAYER_MEMBER);
+	RNA_def_property_boolean_sdna(prop, NULL, "col_mask", 1);
+	RNA_def_property_array(prop, OB_MAX_COL_MASKS);
+	RNA_def_property_ui_text(prop, "Collision Mask", "The groups this object can collide with");
+	RNA_def_property_boolean_funcs(prop, "rna_GameObjectSettings_col_mask_get", "rna_GameObjectSettings_col_mask_set");
 
 	/* lock position */
 	prop = RNA_def_property(srna, "lock_location_x", PROP_BOOLEAN, PROP_NONE);

source/gameengine/Converter/BL_BlenderDataConversion.cpp

@@ -1587,8 +1587,16 @@ static void BL_CreatePhysicsObjectNew(KX_GameObject* gameobj,
 	//bool bRigidBody = (userigidbody == 0);
 
 	// object has physics representation?
-	if (!(blenderobject->gameflag & OB_COLLISION))
+	if (!(blenderobject->gameflag & OB_COLLISION)) {
+		// Respond to all collisions so that Near sensors work on No Collision
+		// objects.
+		gameobj->SetUserCollisionGroup(0xff);
+		gameobj->SetUserCollisionMask(0xff);
 		return;
+	}
+
+	gameobj->SetUserCollisionGroup(blenderobject->col_group);
+	gameobj->SetUserCollisionMask(blenderobject->col_mask);
 
 	// get Root Parent of blenderobject
 	struct Object* parent= blenderobject->parent;

source/gameengine/Ketsji/KX_GameObject.cpp

@@ -531,6 +531,19 @@ void KX_GameObject::ActivateGraphicController(bool recurse)
 	}
 }
 
+void KX_GameObject::SetUserCollisionGroup(short group)
+{
+	m_userCollisionGroup = group;
+}
+void KX_GameObject::SetUserCollisionMask(short mask)
+{
+	m_userCollisionMask = mask;
+}
+
+bool KX_GameObject::CheckCollision(KX_GameObject* other)
+{
+	return this->m_userCollisionGroup & other->m_userCollisionMask;
+}
 
 CValue* KX_GameObject::GetReplica()
 {

source/gameengine/Ketsji/KX_GameObject.h

@@ -98,6 +98,10 @@ protected:
 	bool								m_bIsNegativeScaling;
 	MT_Vector4							m_objectColor;
 
+	// Bit fields for user control over physics collisions
+	short								m_userCollisionGroup;
+	short								m_userCollisionMask;
+
 	// visible = user setting
 	// culled = while rendering, depending on camera
 	bool       							m_bVisible; 
@@ -494,6 +498,13 @@ public:
 	 */
 	void ActivateGraphicController(bool recurse);
 
+	void SetUserCollisionGroup(short filter);
+	void SetUserCollisionMask(short mask);
+	/**
+	* Extra broadphase check for user controllable collisions
+	*/
+	bool CheckCollision(KX_GameObject *other);
+
 	/**
 	 * \section Coordinate system manipulation functions
 	 */

source/gameengine/Physics/Bullet/CcdPhysicsEnvironment.cpp

@@ -2208,10 +2208,29 @@ bool CcdOverlapFilterCallBack::needBroadphaseCollision(btBroadphaseProxy* proxy0
 {
 	btCollisionObject *colObj0, *colObj1;
 	CcdPhysicsController *sensorCtrl, *objCtrl;
+
+	KX_GameObject *kxObj0 = KX_GameObject::GetClientObject(
+			(KX_ClientObjectInfo*)
+			((CcdPhysicsController*)
+					(((btCollisionObject*)proxy0->m_clientObject)->getUserPointer()))
+			->getNewClientInfo());
+	KX_GameObject *kxObj1 = KX_GameObject::GetClientObject(
+			(KX_ClientObjectInfo*)
+			((CcdPhysicsController*)
+					(((btCollisionObject*)proxy1->m_clientObject)->getUserPointer()))
+			->getNewClientInfo());
+
+	// First check the filters. Note that this is called during scene
+	// conversion, so we can't assume the KX_GameObject instances exist. This
+	// may make some objects erroneously collide on the first frame, but the
+	// alternative is to have them erroneously miss.
 	bool collides;
-	// first check the filters
 	collides = (proxy0->m_collisionFilterGroup & proxy1->m_collisionFilterMask) != 0;
 	collides = collides && (proxy1->m_collisionFilterGroup & proxy0->m_collisionFilterMask);
+	if (kxObj0 && kxObj1) {
+		collides = collides && kxObj0->CheckCollision(kxObj1);
+		collides = collides && kxObj1->CheckCollision(kxObj0);
+	}
 	if (!collides)
 		return false;