142 lines
4.8 KiB
Standard ML
142 lines
4.8 KiB
Standard ML
structure TraceJump =
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struct
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structure Trace =
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MakeQuadTreeFold
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(struct
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type env = int
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type state = bool
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fun fold (foldPlatID, nextPlatID, hasFoundNextPlatID) =
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hasFoundNextPlatID orelse foldPlatID = nextPlatID
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end)
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fun traceRightDescent (x, y, nextPlatID, platTree) =
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if x >= Constants.worldWidth orelse y >= Constants.worldHeight then
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(* we hit bounds of screen and saw that there was
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* no way to jump to next nextPlatID *)
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false
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else
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let
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val width = Constants.moveEnemyBy
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val height = Constants.worldHeight - y
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val shouldJumpRight = Trace.foldRegion
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(x, y, width, height, nextPlatID, false, platTree)
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val nextX = x + Constants.moveEnemyBy
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val nextY = y + Constants.moveEnemyBy
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in
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shouldJumpRight
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orelse traceRightDescent (nextX, nextY, nextPlatID, platTree)
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end
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fun traceRightDrop (enemy: GameType.enemy, nextPlatID, platTree) =
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let
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val {x, y, ...} = enemy
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val x = x - Constants.enemySize
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in
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traceRightDescent (x, y, nextPlatID, platTree)
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end
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fun traceRightJumpAscent (x, y, remainingJump, nextPlatID, platTree) =
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(* because value of y parameter is at the top,
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* we subtract the jump limit by the enemy's size,
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* so we only check for places enemy can jump to. *)
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if remainingJump >= Constants.jumpLimit - Constants.enemySize then
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traceRightDescent (x, y, nextPlatID, platTree)
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else
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let
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val width = Constants.moveEnemyBy
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val height = Constants.worldHeight - y
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val shouldJumpRight = Trace.foldRegion
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(x, y, width, height, nextPlatID, false, platTree)
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val nextX = x + Constants.moveEnemyBy
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val nextY = y - Constants.moveEnemyBy
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val nextJump = remainingJump + Constants.moveEnemyBy
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in
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shouldJumpRight
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orelse
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traceRightJumpAscent (nextX, nextY, nextJump, nextPlatID, platTree)
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end
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fun traceRightJump (enemy: GameType.enemy, nextPlatID, platTree) =
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let
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val {x, y, ...} = enemy
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val x = x - Constants.enemySize
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open GameType
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in
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if EnemyPhysics.standingOnArea (x, y, platTree) then
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traceRightJumpAscent (x, y, 0, nextPlatID, platTree)
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else
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case #yAxis enemy of
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JUMPING amt => traceRightJumpAscent (x, y, amt, nextPlatID, platTree)
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| ON_GROUND => traceRightJumpAscent (x, y, 0, nextPlatID, platTree)
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| FALLING => traceRightDescent (x, y, nextPlatID, platTree)
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| DROP_BELOW_PLATFORM => traceRightDescent (x, y, nextPlatID, platTree)
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| FLOATING _ => traceRightDescent (x, y, nextPlatID, platTree)
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end
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fun traceLeftDescent (x, y, nextPlatID, platTree) =
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if x <= 0 orelse y >= Constants.worldHeight then
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false
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else
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let
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val width = Constants.moveEnemyBy
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val height = Constants.worldHeight - y
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val shouldJumpLeft = Trace.foldRegion
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(x, y, width, height, nextPlatID, false, platTree)
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val nextX = x - Constants.moveEnemyBy
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val nextY = y + Constants.moveEnemyBy
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in
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shouldJumpLeft
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orelse traceRightDescent (nextX, nextY, nextPlatID, platTree)
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end
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fun traceLeftDrop (enemy: GameType.enemy, nextPlatID, platTree) =
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let
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val {x, y, ...} = enemy
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val x = x + Constants.enemySize
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in
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traceLeftDescent (x, y, nextPlatID, platTree)
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end
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fun traceLeftJumpAscent (x, y, remainingJump, nextPlatID, platTree) =
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if remainingJump >= Constants.jumpLimit - Constants.enemySize then
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traceLeftDescent (x, y, nextPlatID, platTree)
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else
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let
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val width = Constants.moveEnemyBy
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val height = Constants.worldHeight - y
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val shouldJumpLeft = Trace.foldRegion
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(x, y, width, height, nextPlatID, false, platTree)
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val nextX = x - Constants.moveEnemyBy
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val nextY = y - Constants.moveEnemyBy
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val nextJump = remainingJump + Constants.moveEnemyBy
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in
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shouldJumpLeft
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orelse
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traceLeftJumpAscent (nextX, nextY, nextJump, nextPlatID, platTree)
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end
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fun traceLeftJump (enemy: GameType.enemy, nextPlatID, platTree) =
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let
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val {x, y, ...} = enemy
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val x = x + Constants.enemySize
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open GameType
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in
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if EnemyPhysics.standingOnArea (x, y, platTree) then
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traceLeftJumpAscent (x, y, 0, nextPlatID, platTree)
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else
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case #yAxis enemy of
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JUMPING amt => traceLeftJumpAscent (x, y, amt, nextPlatID, platTree)
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| ON_GROUND => traceLeftJumpAscent (x, y, 0, nextPlatID, platTree)
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| FALLING => traceLeftDescent (x, y, nextPlatID, platTree)
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| DROP_BELOW_PLATFORM => traceLeftDescent (x, y, nextPlatID, platTree)
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| FLOATING _ => traceLeftDescent (x, y, nextPlatID, platTree)
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end
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end
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