58 lines
1.7 KiB
Standard ML
58 lines
1.7 KiB
Standard ML
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structure Player =
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struct
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datatype y_axis = ON_GROUND | FALLING | JUMPING of int
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datatype x_axis = MOVE_LEFT | STAY_STILL | MOVE_RIGHT
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(* width/height *)
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val size = 35
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val moveBy = 5
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val jumpLimit = 55
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type t = {yAxis: y_axis, xAxis: x_axis, health: int, x: int, y: int}
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fun mkPlayer (health, xAxis, yAxis, x, y) =
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{yAxis = yAxis, xAxis = xAxis, health = health, x = x, y = y}
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fun move (player: t) =
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let
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val {yAxis, xAxis, x, y, health} = player
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(* todo: check for wall and platform collisions
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* in case analysis for both axis
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* *)
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val x =
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case xAxis of
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MOVE_LEFT =>
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(* todo: check if we are trying to move left
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* even though player is against wall.
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* In that case, keep same action (it is a sign for us to animate),
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* but don't actually move leftwards. *)
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x - moveBy
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| MOVE_RIGHT => (* todo: check against wall *) x + moveBy
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| STAY_STILL => x
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in
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case yAxis of
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JUMPING jumped =>
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(* check if we hit jump limit;
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* if we did, change to falling case.
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* *)
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if jumped + moveBy <= jumpLimit then
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let
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val jumped = jumped + moveBy
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val yAxis = JUMPING jumped
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val y = y + moveBy
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in
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mkPlayer (health, xAxis, yAxis, x, y)
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end
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else
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mkPlayer (health, xAxis, FALLING, x, y)
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| FALLING =>
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(* todo: keep decrementing and falling down
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* until we hit ground or platform
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* *)
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mkPlayer (health, xAxis, yAxis, x, y - moveBy)
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| ON_GROUND => mkPlayer (health, xAxis, yAxis, x, y)
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end
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end
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