Programatically start cursor drag operation

britzl · britzl · commit b90a7436c2eb · 2021-09-21T23:01:18.000+02:00
diff --git a/examples/accelerometer/accelerometer.collection b/examples/accelerometer/accelerometer.collection
@@ -69,6 +69,7 @@ embedded_instances {
   "linear_damping: 0.1\\n"
   "angular_damping: 0.0\\n"
   "locked_rotation: false\\n"
+  "bullet: false\\n"
   "\"\n"
   "  position {\n"
   "    x: 0.0\n"
@@ -267,6 +268,7 @@ embedded_instances {
   "linear_damping: 0.0\\n"
   "angular_damping: 0.0\\n"
   "locked_rotation: false\\n"
+  "bullet: false\\n"
   "\"\n"
   "  position {\n"
   "    x: 0.0\n"
diff --git a/examples/cursor/bluealien.go b/examples/cursor/bluealien.go
@@ -50,6 +50,7 @@ embedded_components {
   "linear_damping: 0.0\n"
   "angular_damping: 0.0\n"
   "locked_rotation: false\n"
+  "bullet: false\n"
   ""
   position {
     x: 0.0
diff --git a/examples/cursor/cursor.collection b/examples/cursor/cursor.collection
@@ -70,6 +70,7 @@ embedded_instances {
   "linear_damping: 0.0\\n"
   "angular_damping: 0.0\\n"
   "locked_rotation: false\\n"
+  "bullet: false\\n"
   "\"\n"
   "  position {\n"
   "    x: 0.0\n"
diff --git a/examples/cursor/greenalien.go b/examples/cursor/greenalien.go
@@ -84,6 +84,7 @@ embedded_components {
   "linear_damping: 0.0\n"
   "angular_damping: 0.0\n"
   "locked_rotation: false\n"
+  "bullet: false\n"
   ""
   position {
     x: 0.0
diff --git a/examples/cursor_and_camera/bluealien.go b/examples/cursor_and_camera/bluealien.go
@@ -50,6 +50,7 @@ embedded_components {
   "linear_damping: 0.0\n"
   "angular_damping: 0.0\n"
   "locked_rotation: false\n"
+  "bullet: false\n"
   ""
   position {
     x: 0.0
diff --git a/examples/cursor_and_camera/checkpoint.go b/examples/cursor_and_camera/checkpoint.go
@@ -50,6 +50,7 @@ embedded_components {
   "linear_damping: 0.0\n"
   "angular_damping: 0.0\n"
   "locked_rotation: false\n"
+  "bullet: false\n"
   ""
   position {
     x: 0.0
diff --git a/examples/cursor_and_camera/cursor_and_camera.collection b/examples/cursor_and_camera/cursor_and_camera.collection
@@ -124,6 +124,7 @@ embedded_instances {
   "linear_damping: 0.0\\n"
   "angular_damping: 0.0\\n"
   "locked_rotation: false\\n"
+  "bullet: false\\n"
   "\"\n"
   "  position {\n"
   "    x: 0.0\n"
diff --git a/examples/cursor_and_camera/greenalien.go b/examples/cursor_and_camera/greenalien.go
@@ -84,6 +84,7 @@ embedded_components {
   "linear_damping: 0.0\n"
   "angular_damping: 0.0\n"
   "locked_rotation: false\n"
+  "bullet: false\n"
   ""
   position {
     x: 0.0
diff --git a/examples/cursor_and_gesture/cursor_and_gesture.collection b/examples/cursor_and_gesture/cursor_and_gesture.collection
@@ -109,6 +109,7 @@ embedded_instances {
   "linear_damping: 0.0\\n"
   "angular_damping: 0.0\\n"
   "locked_rotation: false\\n"
+  "bullet: false\\n"
   "\"\n"
   "  position {\n"
   "    x: 0.0\n"
diff --git a/examples/cursor_and_gesture/greencircle.go b/examples/cursor_and_gesture/greencircle.go
@@ -50,6 +50,7 @@ embedded_components {
   "linear_damping: 0.0\n"
   "angular_damping: 0.0\n"
   "locked_rotation: false\n"
+  "bullet: false\n"
   ""
   position {
     x: 0.0
diff --git a/in/cursor.lua b/in/cursor.lua
@@ -9,6 +9,13 @@ M.DRAG_END = hash("drag_end")
 M.DRAG_START = hash("drag_start")
 M.CLICKED = hash("clicked")
 
+M.START_DRAGGING = hash("start_dragging")
+
+M.DRAG_MODE_HORIZONTAL = hash("drag_mode_horizontal")
+M.DRAG_MODE_VERTICAL = hash("drag_mode_vertical")
+M.DRAG_MODE_FREE = hash("drag_mode_free")
+
+
 local listeners = {}
 
 local EMPTY = hash("")
@@ -45,5 +52,5 @@ end
 function M.final()
 	listeners[url_to_key()] = nil
 end
-	
-return M
+
+return M
diff --git a/in/cursor.md b/in/cursor.md
@@ -39,6 +39,16 @@ The script will generate messages to game objects the cursor is interacting with
 
 The messages sent to the game object where the cursor script is attached will have `id` and `group` as well as `x` and `y` (from `action.x` and `action.y`) passed in the message.
 
+## Drag objects
+The cursor can drag game objects if the `drag` property is set. You can block drag operations on a single axis through `drag_lock_x` and `drag_lock_y` and you can set the drag threshold (ie how much the cursor needs to move before it is considered a drag event) using `drag_threshold`.
+
+It is also possible to programmatically start a drag operation of a game object:
+
+```
+-- start dragging the game object with id '/go' vertically
+msg.post("#cursor", cursor.START_DRAG, { id = hash("/go"), mode = cursor.DRAG_MODE_VERTICAL })
+```
+
 ## Blocking input events
 You can listen for events generated by the cursor script and block execution of the events. This can be used to block drag, pressed and over events.
 
@@ -51,6 +61,7 @@ Set up a listener for a specific cursor event from a specific cursor script.
 
 Example:
 
+```
 	local cursor = require "in.cursor"
 
 	cursor.listen(msg.url("#cursor"), cursor.DRAG_START, function(message_id, message)
@@ -59,3 +70,4 @@ Example:
 			return true -- return true to block the event
 		end
 	end)
+```
diff --git a/in/cursor.script b/in/cursor.script
@@ -15,10 +15,6 @@ local COLLISION_RESPONSE = hash("collision_response")
 local INPUT = hash("input")
 local EMPTY_FILTER = hash("")
 
-local DRAG_MODE_HORIZONTAL = hash("DRAG_MODE_HORIZONTAL")
-local DRAG_MODE_VERTICAL = hash("DRAG_MODE_VERTICAL")
-local DRAG_MODE_FREE = hash("DRAG_MODE_FREE")
-
 local action_pos = vmath.vector3()
 local function handle_input(self, action_id, action)
 	-- ignore accelerometer
@@ -89,7 +85,7 @@ function init(self)
 	self.released = false
 
 	self.action = {}
-	
+
 	self.state = {
 		pressed = false,
 		dragging = false,
@@ -135,6 +131,13 @@ local function trigger_event(self, game_object_id, game_object_group, action, me
 end
 
 
+local function start_dragging(self, id, mode)
+	self.state.dragging = true
+	self.state.pressed_id = id
+	self.state.drag_mode = mode
+end
+
+
 function update(self, dt)
 	-- skip one frame to give the collision data a chance to properly update
 	-- after a press or release
@@ -149,7 +152,7 @@ function update(self, dt)
 	-- EARLY RELEASE+OUT
 	-- if we are not dragging something and the thing we pressed is no longer under
 	-- the cursor it was either
-	-- 1. deleted by an OVER or PRESSED event 
+	-- 1. deleted by an OVER or PRESSED event
 	-- 2. not draggable and the cursor moved outside while pressed
 	-- in both cases we clear pressed and over state and generate an OUT event
 	if self.state.pressed and self.state.pressed_id and not self.collision_id and not self.state.dragging then
@@ -160,7 +163,7 @@ function update(self, dt)
 			clear_drag_state(self)
 		end
 	end
-	
+
 	--
 	-- RELEASE
 	--
@@ -231,29 +234,28 @@ function update(self, dt)
 	local cursor_pos = go.get_position()
 	if self.drag and self.state.pressed and not self.state.dragging_cancelled and not self.state.dragging then
 		-- handle axis locked drag operations
-		local mode = DRAG_MODE_FREE
+		local mode = cursor.DRAG_MODE_FREE
 		local diff = cursor_pos - self.state.pressed_pos
 		if self.drag_lock_x and not self.drag_lock_y then
 			diff.y = 0
-			mode = DRAG_MODE_HORIZONTAL
+			mode = cursor.DRAG_MODE_HORIZONTAL
 		elseif self.drag_lock_y and not self.drag_lock_x then
 			diff.x = 0
-			mode = DRAG_MODE_VERTICAL
+			mode = cursor.DRAG_MODE_VERTICAL
 		elseif self.drag_lock_x and self.drag_lock_y then
 			if math.abs(diff.x) > math.abs(diff.y) then
 				diff.y = 0
-				mode = DRAG_MODE_HORIZONTAL
+				mode = cursor.DRAG_MODE_HORIZONTAL
 			else
 				diff.x = 0
-				mode = DRAG_MODE_VERTICAL
+				mode = cursor.DRAG_MODE_VERTICAL
 			end
 		end
 		-- start drag?
 		local distance = vmath.length(diff)
 		if distance >= self.drag_threshold then
 			if trigger_event(self, self.state.pressed_id, self.state.pressed_group, self.action, cursor.DRAG_START) then
-				self.state.dragging = true
-				self.state.drag_mode = mode
+				start_dragging(self, self.state.pressed_id, mode)
 			else
 				self.state.dragging_cancelled = true
 			end
@@ -270,9 +272,9 @@ function update(self, dt)
 			trigger_event(self, self.state.pressed_id, self.state.pressed_group, self.action, cursor.RELEASED)
 		else
 			-- restrict movement to a single axis
-			if self.state.drag_mode == DRAG_MODE_HORIZONTAL then
+			if self.state.drag_mode == cursor.DRAG_MODE_HORIZONTAL then
 				cursor_pos.y = self.state.pressed_pos.y
-			elseif self.state.drag_mode == DRAG_MODE_VERTICAL then
+			elseif self.state.drag_mode == cursor.DRAG_MODE_VERTICAL then
 				cursor_pos.x = self.state.pressed_pos.x
 			end
 			-- retain the offset between the cursor and the dragged object and use the z value from the dragged object
@@ -307,6 +309,8 @@ function on_message(self, message_id, message, sender)
 				end
 			end
 		end
+	elseif message_id == cursor.START_DRAGGING then
+		start_dragging(self, message.id, message.mode or cursor.DRAG_MODE_FREE)
 	elseif message_id == INPUT then
 		handle_input(self, message.action_id, message.action)
 	end
