Dual Wielding

14 files changed, 272 insertions, 118 deletions

diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index 29198c427..b4ad10162 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -3261,6 +3261,13 @@ Player Inventory lists
 * `hand`: list containing an override for the empty hand
     * Is not created automatically, use `InvRef:set_size`
     * Is only used to enhance the empty hand's tool capabilities
+* `offhand`: list containing the offhand wielded item.
+    * Will be used for placements and secondary uses if the
+        main hand does not have any node_place_prediction, on_place
+        or on_secondary_use callbacks.
+    * Is passed to on_place and on_secondary_use callbacks; make sure
+        mods are aware of the itemstack not neccessarily being
+        located in the main hand.
 
 Colors
 ======
@@ -4707,13 +4714,13 @@ Privileges
 
 Privileges provide a means for server administrators to give certain players
 access to special abilities in the engine, games or mods.
-For example, game moderators may need to travel instantly to any place in the world, 
+For example, game moderators may need to travel instantly to any place in the world,
 this ability is implemented in `/teleport` command which requires `teleport` privilege.
 
 Registering privileges
 ----------------------
 
-A mod can register a custom privilege using `minetest.register_privilege` function 
+A mod can register a custom privilege using `minetest.register_privilege` function
 to give server administrators fine-grained access control over mod functionality.
 
 For consistency and practical reasons, privileges should strictly increase the abilities of the user.
@@ -4722,7 +4729,7 @@ Do not register custom privileges that e.g. restrict the player from certain in-
 Checking privileges
 -------------------
 
-A mod can call `minetest.check_player_privs` to test whether a player has privileges 
+A mod can call `minetest.check_player_privs` to test whether a player has privileges
 to perform an operation.
 Also, when registering a chat command with `minetest.register_chatcommand` a mod can
 declare privileges that the command requires using the `privs` field of the command
@@ -4786,7 +4793,7 @@ Minetest includes the following settings to control behavior of privileges:
 
    * `default_privs`: defines privileges granted to new players.
    * `basic_privs`: defines privileges that can be granted/revoked by players having
-    the `basic_privs` privilege. This can be used, for example, to give 
+    the `basic_privs` privilege. This can be used, for example, to give
     limited moderation powers to selected users.
 
 'minetest' namespace reference
@@ -7948,8 +7955,10 @@ Used by `minetest.register_node`, `minetest.register_craftitem`, and
         },
 
         on_place = function(itemstack, placer, pointed_thing),
-        -- When the 'place' key was pressed with the item in hand
+        -- When the 'place' key was pressed with the item one of the hands
         -- and a node was pointed at.
+        -- 'itemstack' may be the offhand item iff the main hand has
+        -- no on_place handler and no node_placement_prediction.
         -- Shall place item and return the leftover itemstack
         -- or nil to not modify the inventory.
         -- The placer may be any ObjectRef or nil.
@@ -7957,6 +7966,8 @@ Used by `minetest.register_node`, `minetest.register_craftitem`, and
 
         on_secondary_use = function(itemstack, user, pointed_thing),
         -- Same as on_place but called when not pointing at a node.
+        -- 'itemstack' may be the offhand item iff the main hand has
+        -- no on_secondary_use handler.
         -- Function must return either nil if inventory shall not be modified,
         -- or an itemstack to replace the original itemstack.
         -- The user may be any ObjectRef or nil.
diff --git a/src/client/camera.cpp b/src/client/camera.cpp
index df75c52d6..5ca4e4908 100644
--- a/src/client/camera.cpp
+++ b/src/client/camera.cpp
@@ -45,6 +45,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #define WIELDMESH_AMPLITUDE_X 7.0f
 #define WIELDMESH_AMPLITUDE_Y 10.0f
 
+#define HANDS (int i = 0, s = +1; i <= 1; i++, s *= -1) // i is index, s is sign
+
 Camera::Camera(MapDrawControl &draw_control, Client *client, RenderingEngine *rendering_engine):
 	m_draw_control(draw_control),
 	m_client(client),
@@ -62,9 +64,12 @@ Camera::Camera(MapDrawControl &draw_control, Client *client, RenderingEngine *re
 	// all other 3D scene nodes and before the GUI.
 	m_wieldmgr = smgr->createNewSceneManager();
 	m_wieldmgr->addCameraSceneNode();
-	m_wieldnode = new WieldMeshSceneNode(m_wieldmgr, -1, false);
-	m_wieldnode->setItem(ItemStack(), m_client);
-	m_wieldnode->drop(); // m_wieldmgr grabbed it
+
+	for HANDS {
+		m_wieldnode[i] = new WieldMeshSceneNode(m_wieldmgr, -1, false);
+		m_wieldnode[i]->setItem(ItemStack(), m_client);
+		m_wieldnode[i]->drop(); // m_wieldmgr grabbed it
+	}
 
 	/* TODO: Add a callback function so these can be updated when a setting
 	 *       changes.  At this point in time it doesn't matter (e.g. /set
@@ -151,12 +156,16 @@ void Camera::step(f32 dtime)
 			m_view_bobbing_fall = -1; // Mark the effect as finished
 	}
 
-	bool was_under_zero = m_wield_change_timer < 0;
-	m_wield_change_timer = MYMIN(m_wield_change_timer + dtime, 0.125);
+	for HANDS {
+		bool was_under_zero = m_wield_change_timer[i];
+		m_wield_change_timer[i] = MYMIN(m_wield_change_timer[i] + dtime, 0.125);
+
+		if (m_wield_change_timer[i] >= 0 && was_under_zero) {
+			m_wieldnode[i]->setItem(m_wield_item_next[i], m_client);
 
-	if (m_wield_change_timer >= 0 && was_under_zero) {
-		m_wieldnode->setItem(m_wield_item_next, m_client);
-		m_wieldnode->setNodeLightColor(m_player_light_color);
+			if (i == 0)
+				m_wieldnode[i]->setNodeLightColor(m_player_light_color);
+		}
 	}
 
 	if (m_view_bobbing_state != 0)
@@ -197,24 +206,27 @@ void Camera::step(f32 dtime)
 		}
 	}
 
-	if (m_digging_button != -1) {
-		f32 offset = dtime * 3.5f;
-		float m_digging_anim_was = m_digging_anim;
-		m_digging_anim += offset;
-		if (m_digging_anim >= 1)
-		{
-			m_digging_anim = 0;
-			m_digging_button = -1;
-		}
-		float lim = 0.15;
-		if(m_digging_anim_was < lim && m_digging_anim >= lim)
-		{
-			if (m_digging_button == 0) {
-				m_client->getEventManager()->put(new SimpleTriggerEvent(MtEvent::CAMERA_PUNCH_LEFT));
-			} else if(m_digging_button == 1) {
-				m_client->getEventManager()->put(new SimpleTriggerEvent(MtEvent::CAMERA_PUNCH_RIGHT));
+	for HANDS {
+		if (m_digging_button[i] != -1) {
+			f32 offset = dtime * 3.5f;
+			float m_digging_anim_was = m_digging_anim[i];
+			m_digging_anim[i] += offset;
+			if (m_digging_anim[i] >= 1)
+			{
+				m_digging_anim[i] = 0;
+				m_digging_button[i] = -1;
+			}
+			float lim = 0.15;
+			if(m_digging_anim_was < lim && m_digging_anim[i] >= lim)
+			{
+				if (m_digging_button[i] == 0) {
+					m_client->getEventManager()->put(new SimpleTriggerEvent(MtEvent::CAMERA_PUNCH_LEFT));
+				} else if(m_digging_button[i] == 1) {
+					m_client->getEventManager()->put(new SimpleTriggerEvent(MtEvent::CAMERA_PUNCH_RIGHT));
+				}
 			}
 		}
+
 	}
 }
 
@@ -514,52 +526,68 @@ void Camera::update(LocalPlayer* player, f32 frametime, f32 tool_reload_ratio)
 	if (m_arm_inertia)
 		addArmInertia(player->getYaw());
 
-	// Position the wielded item
-	//v3f wield_position = v3f(45, -35, 65);
-	v3f wield_position = v3f(m_wieldmesh_offset.X, m_wieldmesh_offset.Y, 65);
-	//v3f wield_rotation = v3f(-100, 120, -100);
-	v3f wield_rotation = v3f(-100, 120, -100);
-	wield_position.Y += fabs(m_wield_change_timer)*320 - 40;
-	if(m_digging_anim < 0.05 || m_digging_anim > 0.5)
-	{
-		f32 frac = 1.0;
-		if(m_digging_anim > 0.5)
-			frac = 2.0 * (m_digging_anim - 0.5);
-		// This value starts from 1 and settles to 0
-		f32 ratiothing = std::pow((1.0f - tool_reload_ratio), 0.5f);
-		//f32 ratiothing2 = pow(ratiothing, 0.5f);
-		f32 ratiothing2 = (easeCurve(ratiothing*0.5))*2.0;
-		wield_position.Y -= frac * 25.0 * pow(ratiothing2, 1.7f);
-		//wield_position.Z += frac * 5.0 * ratiothing2;
-		wield_position.X -= frac * 35.0 * pow(ratiothing2, 1.1f);
-		wield_rotation.Y += frac * 70.0 * pow(ratiothing2, 1.4f);
-		//wield_rotation.X -= frac * 15.0 * pow(ratiothing2, 1.4f);
-		//wield_rotation.Z += frac * 15.0 * pow(ratiothing2, 1.0f);
-	}
-	if (m_digging_button != -1)
-	{
-		f32 digfrac = m_digging_anim;
-		wield_position.X -= 50 * sin(pow(digfrac, 0.8f) * M_PI);
-		wield_position.Y += 24 * sin(digfrac * 1.8 * M_PI);
-		wield_position.Z += 25 * 0.5;
-
-		// Euler angles are PURE EVIL, so why not use quaternions?
-		core::quaternion quat_begin(wield_rotation * core::DEGTORAD);
-		core::quaternion quat_end(v3f(80, 30, 100) * core::DEGTORAD);
-		core::quaternion quat_slerp;
-		quat_slerp.slerp(quat_begin, quat_end, sin(digfrac * M_PI));
-		quat_slerp.toEuler(wield_rotation);
-		wield_rotation *= core::RADTODEG;
-	} else {
-		f32 bobfrac = my_modf(m_view_bobbing_anim);
-		wield_position.X -= sin(bobfrac*M_PI*2.0) * 3.0;
-		wield_position.Y += sin(my_modf(bobfrac*2.0)*M_PI) * 3.0;
-	}
-	m_wieldnode->setPosition(wield_position);
-	m_wieldnode->setRotation(wield_rotation);
-
 	m_player_light_color = player->light_color;
-	m_wieldnode->setNodeLightColor(m_player_light_color);
+
+	for HANDS {
+		// Position the wielded item
+		//v3f wield_position = v3f(45, -35, 65);
+		v3f wield_position = v3f(m_wieldmesh_offset.X, m_wieldmesh_offset.Y, 65);
+		//v3f wield_rotation = v3f(-100, 120, -100);
+		v3f wield_rotation = v3f(-100, 120, -100);
+
+		wield_position.Y += fabs(m_wield_change_timer[i])*320 - 40;
+		if(m_digging_anim[i] < 0.05 || m_digging_anim[i] > 0.5)
+		{
+			f32 frac = 1.0;
+			if(m_digging_anim[i] > 0.5)
+				frac = 2.0 * (m_digging_anim[i] - 0.5);
+			// This value starts from 1 and settles to 0
+			f32 ratiothing = std::pow((1.0f - tool_reload_ratio), 0.5f);
+			//f32 ratiothing2 = pow(ratiothing, 0.5f);
+			f32 ratiothing2 = (easeCurve(ratiothing*0.5))*2.0;
+			wield_position.Y -= frac * 25.0 * pow(ratiothing2, 1.7f);
+			//wield_position.Z += frac * 5.0 * ratiothing2;
+			wield_position.X -= frac * 35.0 * pow(ratiothing2, 1.1f);
+			wield_rotation.Y += frac * 70.0 * pow(ratiothing2, 1.4f);
+			//wield_rotation.X -= frac * 15.0 * pow(ratiothing2, 1.4f);
+			//wield_rotation.Z += frac * 15.0 * pow(ratiothing2, 1.0f);
+		}
+		if (m_digging_button[i] != -1)
+		{
+			f32 digfrac = m_digging_anim[i];
+			wield_position.X -= 50 * sin(pow(digfrac, 0.8f) * M_PI);
+			wield_position.Y += 24 * sin(digfrac * 1.8 * M_PI);
+			wield_position.Z += 25 * 0.5;
+
+			// Euler angles are PURE EVIL, so why not use quaternions?
+			core::quaternion quat_begin(wield_rotation * core::DEGTORAD);
+			//core::quaternion quat_end(v3f(s * 80, 30, s * 100) * core::DEGTORAD);
+			core::quaternion quat_end(v3f(80, 30, 100) * core::DEGTORAD);
+			core::quaternion quat_slerp;
+			quat_slerp.slerp(quat_begin, quat_end, sin(digfrac * M_PI));
+			quat_slerp.W *= s;
+			quat_slerp.X *= s;
+			quat_slerp.toEuler(wield_rotation);
+			wield_rotation *= core::RADTODEG;
+			wield_position.X *= s;
+		} else {
+			f32 bobfrac = my_modf(m_view_bobbing_anim);
+			wield_position.X *= s;
+			wield_position.X -= sin(bobfrac*M_PI*2.0+M_PI*i) * 3.0 * s;
+			wield_position.Y += sin(my_modf(bobfrac*2.0)*M_PI+M_PI*i) * 3.0;
+		}
+
+		m_wieldnode[i]->setPosition(wield_position);
+		m_wieldnode[i]->setRotation(wield_rotation);
+
+		m_wieldnode[i]->setNodeLightColor(m_player_light_color);
+
+		if (i == 1) {
+			m_wieldnode[i]->setVisible(
+				(m_wield_item_next[i].name != "" && m_wield_change_timer[i] > 0)
+				|| (m_offhand_wield_item_old && m_wield_change_timer[i] < 0));
+		}
+	}
 
 	// Set render distance
 	updateViewingRange();
@@ -607,21 +635,23 @@ void Camera::updateViewingRange()
 	m_cameranode->setFarValue((viewing_range < 2000) ? 2000 * BS : viewing_range * BS);
 }
 
-void Camera::setDigging(s32 button)
+void Camera::setDigging(s32 button, int hand)
 {
-	if (m_digging_button == -1)
-		m_digging_button = button;
+	if (m_digging_button[hand] == -1)
+		m_digging_button[hand] = button;
 }
 
-void Camera::wield(const ItemStack &item)
+void Camera::wield(const ItemStack &item, int hand)
 {
-	if (item.name != m_wield_item_next.name ||
-			item.metadata != m_wield_item_next.metadata) {
-		m_wield_item_next = item;
-		if (m_wield_change_timer > 0)
-			m_wield_change_timer = -m_wield_change_timer;
-		else if (m_wield_change_timer == 0)
-			m_wield_change_timer = -0.001;
+	if (item.name != m_wield_item_next[hand].name ||
+			item.metadata != m_wield_item_next[hand].metadata) {
+		if (hand == 1)
+			m_offhand_wield_item_old = m_wield_item_next[hand].name != "";
+		m_wield_item_next[hand] = item;
+		if (m_wield_change_timer[hand] > 0)
+			m_wield_change_timer[hand] = -m_wield_change_timer[hand];
+		else if (m_wield_change_timer[hand] == 0)
+			m_wield_change_timer[hand] = -0.001;
 	}
 }
 
diff --git a/src/client/camera.h b/src/client/camera.h
index cbf248d97..bfc403cad 100644
--- a/src/client/camera.h
+++ b/src/client/camera.h
@@ -146,11 +146,12 @@ public:
 	void updateViewingRange();
 
 	// Start digging animation
-	// Pass 0 for left click, 1 for right click
-	void setDigging(s32 button);
+	// button: Pass 0 for left click, 1 for right click
+	// hand: 0 for main hand, 1 for offhand
+	void setDigging(s32 button, int hand);
 
 	// Replace the wielded item mesh
-	void wield(const ItemStack &item);
+	void wield(const ItemStack &item, int hand);
 
 	// Draw the wielded tool.
 	// This has to happen *after* the main scene is drawn.
@@ -196,7 +197,7 @@ private:
 	scene::ICameraSceneNode *m_cameranode = nullptr;
 
 	scene::ISceneManager *m_wieldmgr = nullptr;
-	WieldMeshSceneNode *m_wieldnode = nullptr;
+	WieldMeshSceneNode *m_wieldnode[2] = {nullptr, nullptr};
 
 	// draw control
 	MapDrawControl& m_draw_control;
@@ -246,15 +247,17 @@ private:
 	f32 m_view_bobbing_fall = 0.0f;
 
 	// Digging animation frame (0 <= m_digging_anim < 1)
-	f32 m_digging_anim = 0.0f;
+	f32 m_digging_anim[2] = {0.0f, 0.0f};
+
 	// If -1, no digging animation
 	// If 0, left-click digging animation
 	// If 1, right-click digging animation
-	s32 m_digging_button = -1;
+	s32 m_digging_button[2] = {-1, -1};
 
 	// Animation when changing wielded item
-	f32 m_wield_change_timer = 0.125f;
-	ItemStack m_wield_item_next;
+	f32 m_wield_change_timer[2] = {0.125f, 0.125f};
+	ItemStack m_wield_item_next[2];
+	bool m_offhand_wield_item_old;
 
 	CameraMode m_camera_mode = CAMERA_MODE_FIRST;
 
diff --git a/src/client/client.cpp b/src/client/client.cpp
index 31bbf2463..0f6cd36da 100644
--- a/src/client/client.cpp
+++ b/src/client/client.cpp
@@ -1487,6 +1487,8 @@ bool Client::updateWieldedItem()
 		list->setModified(false);
 	if (auto *list = player->inventory.getList("hand"))
 		list->setModified(false);
+	if (auto *list = player->inventory.getList("offhand"))
+		list->setModified(false);
 
 	return true;
 }
diff --git a/src/client/client.h b/src/client/client.h
index bdcc2a3dd..b920f7575 100644
--- a/src/client/client.h
+++ b/src/client/client.h
@@ -275,6 +275,7 @@ public:
 	// Returns true if the inventory of the local player has been
 	// updated from the server. If it is true, it is set to false.
 	bool updateWieldedItem();
+	bool updateOffhandWieldedItem();
 
 	/* InventoryManager interface */
 	Inventory* getInventory(const InventoryLocation &loc) override;
diff --git a/src/client/game.cpp b/src/client/game.cpp
index caa83ce13..bc27920fc 100644
--- a/src/client/game.cpp
+++ b/src/client/game.cpp
@@ -746,7 +746,8 @@ protected:
 			bool look_for_object, const v3s16 &camera_offset);
 	void handlePointingAtNothing(const ItemStack &playerItem);
 	void handlePointingAtNode(const PointedThing &pointed,
-			const ItemStack &selected_item, const ItemStack &hand_item, f32 dtime);
+			const ItemStack &selected_item, const ItemStack &hand_item,
+			const ItemStack &place_item, f32 dtime);
 	void handlePointingAtObject(const PointedThing &pointed, const ItemStack &playeritem,
 			const v3f &player_position, bool show_debug);
 	void handleDigging(const PointedThing &pointed, const v3s16 &nodepos,
@@ -3055,7 +3056,7 @@ void Game::processPlayerInteraction(f32 dtime, bool show_hud)
 		Calculate what block is the crosshair pointing to
 	*/
 
-	ItemStack selected_item, hand_item;
+	ItemStack selected_item, hand_item, offhand_item, use_item;
 	const ItemStack &tool_item = player->getWieldedItem(&selected_item, &hand_item);
 
 	const ItemDefinition &selected_def = selected_item.getDefinition(itemdef_manager);
@@ -3098,6 +3099,8 @@ void Game::processPlayerInteraction(f32 dtime, bool show_hud)
 			!runData.btn_down_for_dig,
 			camera_offset);
 
+	player->getOffhandWieldedItem(&offhand_item, &use_item, itemdef_manager, pointed);
+
 	if (pointed != runData.pointed_old)
 		infostream << "Pointing at " << pointed.dump() << std::endl;
 
@@ -3161,7 +3164,7 @@ void Game::processPlayerInteraction(f32 dtime, bool show_hud)
 				!client->getScript()->on_item_use(selected_item, pointed)))
 			client->interact(INTERACT_USE, pointed);
 	} else if (pointed.type == POINTEDTHING_NODE) {
-		handlePointingAtNode(pointed, selected_item, hand_item, dtime);
+		handlePointingAtNode(pointed, selected_item, hand_item, use_item, dtime);
 	} else if (pointed.type == POINTEDTHING_OBJECT) {
 		v3f player_position  = player->getPosition();
 		bool basic_debug_allowed = client->checkPrivilege("debug") || (player->hud_flags & HUD_FLAG_BASIC_DEBUG);
@@ -3174,13 +3177,13 @@ void Game::processPlayerInteraction(f32 dtime, bool show_hud)
 		if (wasKeyPressed(KeyType::DIG) && client->modsLoaded())
 			client->getScript()->on_item_use(selected_item, pointed);
 	} else if (wasKeyPressed(KeyType::PLACE)) {
-		handlePointingAtNothing(selected_item);
+		handlePointingAtNothing(use_item);
 	}
 
 	runData.pointed_old = pointed;
 
 	if (runData.punching || wasKeyPressed(KeyType::DIG))
-		camera->setDigging(0); // dig animation
+		camera->setDigging(0, 0); // dig animation
 
 	input->clearWasKeyPressed();
 	input->clearWasKeyReleased();
@@ -3300,7 +3303,8 @@ void Game::handlePointingAtNothing(const ItemStack &playerItem)
 
 
 void Game::handlePointingAtNode(const PointedThing &pointed,
-	const ItemStack &selected_item, const ItemStack &hand_item, f32 dtime)
+	const ItemStack &selected_item, const ItemStack &hand_item,
+	const ItemStack &place_item, f32 dtime)
 {
 	v3s16 nodepos = pointed.node_undersurface;
 	v3s16 neighbourpos = pointed.node_abovesurface;
@@ -3338,7 +3342,10 @@ void Game::handlePointingAtNode(const PointedThing &pointed,
 		infostream << "Place button pressed while looking at ground" << std::endl;
 
 		// Placing animation (always shown for feedback)
-		camera->setDigging(1);
+		if (place_item == selected_item)
+			camera->setDigging(1, 0);
+		else
+			camera->setDigging(1, 1);
 
 		soundmaker->m_player_rightpunch_sound = SimpleSoundSpec();
 
@@ -3346,8 +3353,8 @@ void Game::handlePointingAtNode(const PointedThing &pointed,
 		// make that happen
 		// And also set the sound and send the interact
 		// But first check for meta formspec and rightclickable
-		auto &def = selected_item.getDefinition(itemdef_manager);
-		bool placed = nodePlacement(def, selected_item, nodepos, neighbourpos,
+		auto &def = place_item.getDefinition(itemdef_manager);
+		bool placed = nodePlacement(def, place_item, nodepos, neighbourpos,
 			pointed, meta);
 
 		if (placed && client->modsLoaded())
@@ -3737,7 +3744,7 @@ void Game::handleDigging(const PointedThing &pointed, const v3s16 &nodepos,
 		client->setCrack(-1, nodepos);
 	}
 
-	camera->setDigging(0);  // Dig animation
+	camera->setDigging(0, 0);  // Dig animation
 }
 
 void Game::updateFrame(ProfilerGraph *graph, RunStats *stats, f32 dtime,
@@ -3897,9 +3904,11 @@ void Game::updateFrame(ProfilerGraph *graph, RunStats *stats, f32 dtime,
 
 	if (client->updateWieldedItem()) {
 		// Update wielded tool
-		ItemStack selected_item, hand_item;
+		ItemStack selected_item, hand_item, offhand_item;
 		ItemStack &tool_item = player->getWieldedItem(&selected_item, &hand_item);
-		camera->wield(tool_item);
+		camera->wield(tool_item, 0);
+		player->getOffhandWieldedItem(&offhand_item, nullptr, itemdef_manager, PointedThing());
+		camera->wield(offhand_item, 1);
 	}
 
 	/*
diff --git a/src/itemdef.cpp b/src/itemdef.cpp
index a34805b8e..ca24c6cfa 100644
--- a/src/itemdef.cpp
+++ b/src/itemdef.cpp
@@ -76,6 +76,8 @@ ItemDefinition& ItemDefinition::operator=(const ItemDefinition &def)
 	groups = def.groups;
 	node_placement_prediction = def.node_placement_prediction;
 	place_param2 = def.place_param2;
+	has_on_place = def.has_on_place;
+	has_on_secondary_use = def.has_on_secondary_use;
 	sound_place = def.sound_place;
 	sound_place_failed = def.sound_place_failed;
 	range = def.range;
@@ -120,6 +122,8 @@ void ItemDefinition::reset()
 	range = -1;
 	node_placement_prediction = "";
 	place_param2 = 0;
+	has_on_place = false;
+	has_on_secondary_use = false;
 }
 
 void ItemDefinition::serialize(std::ostream &os, u16 protocol_version) const
@@ -166,6 +170,8 @@ void ItemDefinition::serialize(std::ostream &os, u16 protocol_version) const
 	os << serializeString16(short_description);
 
 	os << place_param2;
+	writeU8(os, has_on_place);
+	writeU8(os, has_on_secondary_use);
 }
 
 void ItemDefinition::deSerialize(std::istream &is, u16 protocol_version)
@@ -220,6 +226,8 @@ void ItemDefinition::deSerialize(std::istream &is, u16 protocol_version)
 		short_description = deSerializeString16(is);
 
 		place_param2 = readU8(is); // 0 if missing
+		has_on_place = readU8(is);
+		has_on_secondary_use = readU8(is);
 	} catch(SerializationError &e) {};
 }
 
diff --git a/src/itemdef.h b/src/itemdef.h
index 035717379..9d9eba2b8 100644
--- a/src/itemdef.h
+++ b/src/itemdef.h
@@ -87,6 +87,8 @@ struct ItemDefinition
 	// "" = no prediction
 	std::string node_placement_prediction;
 	u8 place_param2;
+	bool has_on_place;
+	bool has_on_secondary_use;
 
 	/*
 		Some helpful methods
diff --git a/src/network/serverpackethandler.cpp b/src/network/serverpackethandler.cpp
index 4b9de488c..25e5d49e2 100644
--- a/src/network/serverpackethandler.cpp
+++ b/src/network/serverpackethandler.cpp
@@ -911,6 +911,13 @@ static inline void getWieldedItem(const PlayerSAO *playersao, Optional<ItemStack
 	playersao->getWieldedItem(&(*ret));
 }
 
+static inline bool getOffhandWieldedItem(const PlayerSAO *playersao, Optional<ItemStack> &offhand, Optional<ItemStack> &place, IItemDefManager *idef, const PointedThing &pointed)
+{
+	offhand = ItemStack();
+	place = ItemStack();
+	return playersao->getOffhandWieldedItem(&(*offhand), &(*place), idef, pointed);
+}
+
 void Server::handleCommand_Interact(NetworkPacket *pkt)
 {
 	/*
@@ -1219,15 +1226,16 @@ void Server::handleCommand_Interact(NetworkPacket *pkt)
 
 	// Place block or right-click object
 	case INTERACT_PLACE: {
-		Optional<ItemStack> selected_item;
-		getWieldedItem(playersao, selected_item);
+		Optional<ItemStack> main_item, offhand_item, place_item;
+		getWieldedItem(playersao, main_item);
+		bool use_offhand = getOffhandWieldedItem(playersao, offhand_item, place_item, m_itemdef, pointed);
 
 		// Reset build time counter
 		if (pointed.type == POINTEDTHING_NODE &&
-				selected_item->getDefinition(m_itemdef).type == ITEM_NODE)
+				place_item->getDefinition(m_itemdef).type == ITEM_NODE)
 			getClient(peer_id)->m_time_from_building = 0.0;
 
-		const bool had_prediction = !selected_item->getDefinition(m_itemdef).
+		const bool had_prediction = !place_item->getDefinition(m_itemdef).
 			node_placement_prediction.empty();
 
 		if (pointed.type == POINTEDTHING_OBJECT) {
@@ -1242,17 +1250,21 @@ void Server::handleCommand_Interact(NetworkPacket *pkt)
 					<< pointed_object->getDescription() << std::endl;
 
 			// Do stuff
-			if (m_script->item_OnSecondaryUse(selected_item, playersao, pointed)) {
-				if (selected_item.has_value() && playersao->setWieldedItem(*selected_item))
+			if (m_script->item_OnSecondaryUse(use_offhand ? offhand_item : main_item, playersao, pointed)) {
+				if (use_offhand
+						? (offhand_item.has_value() && playersao->setOffhandWieldedItem(*offhand_item))
+						: (main_item.has_value() && playersao->setWieldedItem(*main_item)))
 					SendInventory(playersao, true);
 			}
 
 			pointed_object->rightClick(playersao);
-		} else if (m_script->item_OnPlace(selected_item, playersao, pointed)) {
+		} else if (m_script->item_OnPlace(use_offhand ? offhand_item : main_item, playersao, pointed)) {
 			// Placement was handled in lua
 
 			// Apply returned ItemStack
-			if (selected_item.has_value() && playersao->setWieldedItem(*selected_item))
+			if (use_offhand
+					? (offhand_item.has_value() && playersao->setOffhandWieldedItem(*offhand_item))
+					: (main_item.has_value() && playersao->setWieldedItem(*main_item)))
 				SendInventory(playersao, true);
 		}
 
@@ -1295,17 +1307,20 @@ void Server::handleCommand_Interact(NetworkPacket *pkt)
 
 	// Rightclick air
 	case INTERACT_ACTIVATE: {
-		Optional<ItemStack> selected_item;
-		getWieldedItem(playersao, selected_item);
+		Optional<ItemStack> main_item, offhand_item, place_item;
+		getWieldedItem(playersao, main_item);
+		bool use_offhand = getOffhandWieldedItem(playersao, offhand_item, place_item, m_itemdef, pointed);
 
 		actionstream << player->getName() << " activates "
-				<< selected_item->name << std::endl;
+				<< place_item->name << std::endl;
 
 		pointed.type = POINTEDTHING_NOTHING; // can only ever be NOTHING
 
-		if (m_script->item_OnSecondaryUse(selected_item, playersao, pointed)) {
+		if (m_script->item_OnSecondaryUse(use_offhand ? offhand_item : main_item, playersao, pointed)) {
 			// Apply returned ItemStack
-			if (selected_item.has_value() && playersao->setWieldedItem(*selected_item))
+			if (use_offhand
+					? (offhand_item.has_value() && playersao->setOffhandWieldedItem(*offhand_item))
+					: (main_item.has_value() && playersao->setWieldedItem(*main_item)))
 				SendInventory(playersao, true);
 		}
 
diff --git a/src/player.cpp b/src/player.cpp
index 1e064c1da..e5a8d3b0a 100644
--- a/src/player.cpp
+++ b/src/player.cpp
@@ -114,6 +114,46 @@ ItemStack &Player::getWieldedItem(ItemStack *selected, ItemStack *hand) const
 	return (hand && selected->name.empty()) ? *hand : *selected;
 }
 
+bool Player::getOffhandWieldedItem(ItemStack *offhand, ItemStack *place, IItemDefManager *idef, const PointedThing &pointed) const
+{
+	assert(offhand);
+
+	ItemStack main;
+
+	const InventoryList *mlist = inventory.getList("main");
+	const InventoryList *olist = inventory.getList("offhand");
+
+	if (olist)
+		*offhand = olist->getItem(0);
+
+	if (mlist && m_wield_index < mlist->getSize())
+		main = mlist->getItem(m_wield_index);
+
+	const ItemDefinition &main_def = main.getDefinition(idef);
+	const ItemDefinition &offhand_def = offhand->getDefinition(idef);
+	bool main_usable, offhand_usable;
+
+	// figure out which item to use for placements
+
+	if (pointed.type == POINTEDTHING_NODE) {
+		// an item can be used on nodes if it has a place handler or prediction
+		main_usable = main_def.has_on_place || main_def.node_placement_prediction != "";
+		offhand_usable = offhand_def.has_on_place || offhand_def.node_placement_prediction != "";
+	} else {
+		// an item can be used on anything else if it has a secondary use handler
+		main_usable = main_def.has_on_secondary_use;
+		offhand_usable = offhand_def.has_on_secondary_use;
+	}
+
+	// main hand has priority
+	bool use_offhand = offhand_usable && !main_usable;
+
+	if (place)
+		*place = use_offhand ? *offhand : main;
+
+	return use_offhand;
+}
+
 u32 Player::addHud(HudElement *toadd)
 {
 	MutexAutoLock lock(m_mutex);
diff --git a/src/player.h b/src/player.h
index beca82f66..248ae9388 100644
--- a/src/player.h
+++ b/src/player.h
@@ -24,6 +24,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "constants.h"
 #include "network/networkprotocol.h"
 #include "util/basic_macros.h"
+#include "util/pointedthing.h"
 #include <list>
 #include <mutex>
 
@@ -187,6 +188,10 @@ public:
 
 	// Returns non-empty `selected` ItemStack. `hand` is a fallback, if specified
 	ItemStack &getWieldedItem(ItemStack *selected, ItemStack *hand) const;
+
+	// item currently in secondary hand is returned in `offhand`
+	// item to use for place / secondary_use (either main or offhand) is (optionally) returned in `place`
+	bool getOffhandWieldedItem(ItemStack *offhand, ItemStack *place, IItemDefManager *idef, const PointedThing &pointed) const;
 	void setWieldIndex(u16 index);
 	u16 getWieldIndex() const { return m_wield_index; }
 
diff --git a/src/script/common/c_content.cpp b/src/script/common/c_content.cpp
index 166980025..5c112d1d1 100644
--- a/src/script/common/c_content.cpp
+++ b/src/script/common/c_content.cpp
@@ -81,6 +81,16 @@ void read_item_definition(lua_State* L, int index,
 	def.usable = lua_isfunction(L, -1);
 	lua_pop(L, 1);
 
+	lua_pushstring(L, "on_place");
+	lua_rawget(L, index);
+	def.has_on_place = lua_isfunction(L, -1);
+	lua_pop(L, 1);
+
+	lua_pushstring(L, "on_secondary_use");
+	lua_rawget(L, index);
+	def.has_on_secondary_use = lua_isfunction(L, -1);
+	lua_pop(L, 1);
+
 	getboolfield(L, index, "liquids_pointable", def.liquids_pointable);
 
 	lua_getfield(L, index, "tool_capabilities");
diff --git a/src/server/player_sao.cpp b/src/server/player_sao.cpp
index a58a0397f..7b134b391 100644
--- a/src/server/player_sao.cpp
+++ b/src/server/player_sao.cpp
@@ -525,6 +525,11 @@ ItemStack PlayerSAO::getWieldedItem(ItemStack *selected, ItemStack *hand) const
 	return m_player->getWieldedItem(selected, hand);
 }
 
+bool PlayerSAO::getOffhandWieldedItem(ItemStack *offhand, ItemStack *place, IItemDefManager *itemdef_manager, PointedThing pointed) const
+{
+	return m_player->getOffhandWieldedItem(offhand, place, itemdef_manager, pointed);
+}
+
 bool PlayerSAO::setWieldedItem(const ItemStack &item)
 {
 	InventoryList *mlist = m_player->inventory.getList(getWieldList());
@@ -535,6 +540,16 @@ bool PlayerSAO::setWieldedItem(const ItemStack &item)
 	return false;
 }
 
+bool PlayerSAO::setOffhandWieldedItem(const ItemStack &item)
+{
+	InventoryList *olist = m_player->inventory.getList("offhand");
+	if (olist) {
+		olist->changeItem(0, item);
+		return true;
+	}
+	return false;
+}
+
 void PlayerSAO::disconnected()
 {
 	m_peer_id = PEER_ID_INEXISTENT;
diff --git a/src/server/player_sao.h b/src/server/player_sao.h
index 5f48cae67..8bf64bea7 100644
--- a/src/server/player_sao.h
+++ b/src/server/player_sao.h
@@ -24,6 +24,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "network/networkprotocol.h"
 #include "unit_sao.h"
 #include "util/numeric.h"
+#include "util/pointedthing.h"
 
 /*
 	PlayerSAO needs some internals exposed.
@@ -130,7 +131,9 @@ public:
 	std::string getWieldList() const override { return "main"; }
 	u16 getWieldIndex() const override;
 	ItemStack getWieldedItem(ItemStack *selected, ItemStack *hand = nullptr) const override;
+	bool getOffhandWieldedItem(ItemStack *offhand, ItemStack *place, IItemDefManager *itemdef_manager, PointedThing pointed) const;
 	bool setWieldedItem(const ItemStack &item) override;
+	bool setOffhandWieldedItem(const ItemStack &item);
 
 	/*
 		PlayerSAO-specific