54 lines
1.7 KiB
Text
54 lines
1.7 KiB
Text
go.property("acceleration", 100)
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go.property("deceleration", 200)
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go.property("max_speed", 400)
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go.property("wheel_base", 40) -- pixels between left and right wheels
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local UP = vmath.vector3(0, 1, 0)
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function init(self)
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msg.post(".", "acquire_input_focus")
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self.left_speed = 0
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self.right_speed = 0
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self.left_input = false
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self.right_input = false
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end
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function update(self, dt)
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-- each wheel accelerates when its key is held, decelerates otherwise
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if self.left_input then
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self.left_speed = math.min(self.left_speed + self.acceleration * dt, self.max_speed)
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else
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self.left_speed = math.max(self.left_speed - self.deceleration * dt, 0)
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end
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if self.right_input then
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self.right_speed = math.min(self.right_speed + self.acceleration * dt, self.max_speed)
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else
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self.right_speed = math.max(self.right_speed - self.deceleration * dt, 0)
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end
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-- differential drive: speed difference creates rotation, average creates forward motion
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local linear_speed = (self.left_speed + self.right_speed) / 2
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local angular_vel = (self.right_speed - self.left_speed) / self.wheel_base
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local rot = go.get_rotation()
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rot = rot * vmath.quat_rotation_z(angular_vel * dt)
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go.set_rotation(rot)
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local p = go.get_position()
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p = p + vmath.rotate(rot, UP * linear_speed * dt)
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go.set_position(p)
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-- reset each frame (on_input re-sets if key is still held)
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self.left_input = false
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self.right_input = false
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end
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function on_input(self, action_id, action)
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if action_id == hash("a_key") then
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self.left_input = true
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elseif action_id == hash("d_key") then
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self.right_input = true
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end
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end
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