79 lines
2.5 KiB
Standard ML
79 lines
2.5 KiB
Standard ML
structure TraceJump =
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struct
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structure Trace = MakeQuadTreeFold (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 traceRightJumpDescent (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 =
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Trace.foldRegion (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 orelse
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traceRightJumpDescent (nextX, nextY, nextPlatID, platTree)
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end
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fun traceRightDrop (enemy, nextPlatID, platTree) =
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let
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open GameType
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val {x, y, ...}: enemy = enemy
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val x = x - Constants.enemySize
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in
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traceRightJumpDescent (x, y, nextPlatID, platTree)
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end
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fun traceRightJumpAscent (x, y, remainingJump, nextPlatID, platTree) =
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if remainingJump >= Constants.jumpLimit then
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traceRightJumpDescent (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 =
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Trace.foldRegion (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 orelse
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traceRightJumpAscent (nextX, nextY, nextJump, nextPlatID, platTree)
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end
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fun traceRightJump (enemy, nextPlatID, platTree) =
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let
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open GameType
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val {x, y, ...}: enemy = enemy
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val x = x - Constants.enemySize
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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 =>
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traceRightJumpAscent (x, y, amt, nextPlatID, platTree)
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| ON_GROUND =>
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traceRightJumpAscent (x, y, 0, nextPlatID, platTree)
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| FALLING =>
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traceRightJumpDescent (x, y, nextPlatID, platTree)
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| DROP_BELOW_PLATFORM =>
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traceRightJumpDescent (x, y, nextPlatID, platTree)
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| FLOATING _ =>
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traceRightJumpDescent (x, y, nextPlatID, platTree)
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end
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end
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