86 lines
2.7 KiB
Text
86 lines
2.7 KiB
Text
local ACCELERATION = 100
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local DECELERATION = 200
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local MAX_SPEED = 400
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local WHEEL_BASE = 80
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local UP = vmath.vector3(0, 1, 0)
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local DIRECTIONS = { "n", "ne", "e", "se", "s", "sw", "w", "nw" }
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local function get_direction(rot)
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local forward = vmath.rotate(rot, UP)
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local angle = math.deg(math.atan2(forward.x, forward.y))
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if angle < 0 then angle = angle + 360 end
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local index = math.floor((angle + 22.5) / 45) % 8 + 1
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return DIRECTIONS[index]
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end
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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.current_anim = nil
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self.left_fwd = false
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self.left_rev = false
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self.right_fwd = false
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self.right_rev = false
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end
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local function update_speed(speed, drive, dt)
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if drive ~= 0 then
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local target = drive * MAX_SPEED
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local step = ACCELERATION * dt
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if speed < target then
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return math.min(speed + step, target)
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else
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return math.max(speed - step, target)
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end
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else
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local step = DECELERATION * dt
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if speed > 0 then
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return math.max(speed - step, 0)
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else
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return math.min(speed + step, 0)
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end
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end
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end
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function update(self, dt)
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local left_drive = (self.left_fwd and 1 or 0) - (self.left_rev and 1 or 0)
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local right_drive = (self.right_fwd and 1 or 0) - (self.right_rev and 1 or 0)
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self.left_speed = update_speed(self.left_speed, left_drive, dt)
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self.right_speed = update_speed(self.right_speed, right_drive, dt)
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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) / WHEEL_BASE
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-- pprint({rot_changes = angular_vel * dt})
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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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go.set_rotation(vmath.conj(rot), "body")
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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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-- switch animation when facing direction changes
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local dir = get_direction(rot)
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if dir ~= self.current_anim then
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self.current_anim = dir
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msg.post("body#body", "play_animation", { id = hash(dir) })
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end
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end
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function on_input(self, action_id, action)
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local held = action.pressed or not action.released
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if action_id == hash("a_key") then self.left_fwd = held
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elseif action_id == hash("q_key") then self.left_rev = held
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elseif action_id == hash("d_key") then self.right_fwd = held
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elseif action_id == hash("e_key") then self.right_rev = held
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end
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end
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