This example shows how to rotate a game object to look at the mouse cursor. It reads the mouse position in on_input
and uses the mathematical function math.atan2(x, y)
to calculate the angle between the ray to the point to look at and the positive x-axis. This angle is used to set the rotation of the game object to always look at the mouse position.
look_at.script
function init(self)
-- make sure the script will receive user input
msg.post(".", "acquire_input_focus")
end
local function look_at(target_position)
-- own positon
local my_position = go.get_position()
-- calculate the angle that this object has to rotate to look at the given point
local angle = math.atan2(my_position.x - target_position.x, target_position.y - my_position.y)
-- set rotation as a quaternion
go.set_rotation(vmath.quat_rotation_z(angle))
end
function on_input(self, action_id, action)
-- mouse/finger movement has action_id set to nil
if not action_id then
-- the position to look at (mouse/finger)
local target_position = vmath.vector3(action.x, action.y, 0)
-- rotate this object to look at the target position
look_at(target_position)
end
end
If you want to play with these examples, you can get the project on Github.
Do you want to see more examples? Why not write a few yourself and submit a pull request? We love contributions.
GITHUB