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use an immutable vector (always of length 4) for representing quad tree's internal nodes

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Humza Shahid
2025-01-31 06:24:51 +00:00
parent 76c5f9d662
commit 547b5bac97
3 changed files with 54 additions and 47 deletions
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68
fcore/quad-tree.sml
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@@ -97,10 +97,7 @@ struct
val br = mkBottomRight (x, y, w, h, br)
in
NODE
{ topLeft = tl
, topRight = tr
, bottomLeft = bl
, bottomRight = br
{ nodes = Vector.fromList [tl, tr, bl, br]
, x = x
, y = y
, w = w
@@ -130,22 +127,19 @@ struct
fun insert (iX, iY, iW, iH, itemID, tree: t) =
case tree of
NODE {topLeft, topRight, bottomLeft, bottomRight, x, y, w, h} =>
NODE {nodes, x, y, w, h} =>
if isCollidingPlus (iX, iY, iW, iH, x, y, w, h) then
let
(* we are not necessarily inserting into all nodes.
* If isCollidingPlus returns false recursively,
* we return the same node back. *)
val tl = insert (iX, iY, iW, iH, itemID, topLeft)
val tr = insert (iX, iY, iW, iH, itemID, topRight)
val bl = insert (iX, iY, iW, iH, itemID, bottomLeft)
val br = insert (iX, iY, iW, iH, itemID, bottomRight)
val tl = insert (iX, iY, iW, iH, itemID, Vector.sub (nodes, tlIdx))
val tr = insert (iX, iY, iW, iH, itemID, Vector.sub (nodes, trIdx))
val bl = insert (iX, iY, iW, iH, itemID, Vector.sub (nodes, blIdx))
val br = insert (iX, iY, iW, iH, itemID, Vector.sub (nodes, brIdx))
in
NODE
{ topLeft = tl
, topRight = tr
, bottomLeft = bl
, bottomRight = br
{ nodes = Vector.fromList [tl, tr, bl, br]
, x = x
, y = y
, w = w
@@ -206,16 +200,19 @@ struct
fun getCollisionsAll (iX, iY, iW, iH, itemID, acc, tree) =
case tree of
NODE {topLeft, topRight, bottomLeft, bottomRight, x, y, w, h} =>
NODE {nodes, x, y, w, h} =>
if isCollidingPlus (iX, iY, iW, iH, x, y, w, h) then
let
val acc = getCollisionsAll (iX, iY, iW, iH, itemID, acc, topLeft)
val acc =
getCollisionsAll (iX, iY, iW, iH, itemID, acc, Vector.sub (nodes, tlIdx))
val acc = getCollisionsAll (iX, iY, iW, iH, itemID, acc, topRight)
val acc =
getCollisionsAll (iX, iY, iW, iH, itemID, acc, Vector.sub (nodes, trIdx))
val acc = getCollisionsAll (iX, iY, iW, iH, itemID, acc, bottomLeft)
val acc =
getCollisionsAll (iX, iY, iW, iH, itemID, acc, Vector.sub (nodes, blIdx))
in
getCollisionsAll (iX, iY, iW, iH, itemID, acc, bottomRight)
getCollisionsAll (iX, iY, iW, iH, itemID, acc, Vector.sub (nodes, brIdx))
end
else
acc
@@ -227,17 +224,20 @@ struct
fun helpGetCollisions (iX, iY, iW, iH, itemID, acc, tree: t) =
case tree of
NODE {topLeft, topRight, bottomLeft, bottomRight, x, y, w, h} =>
NODE {nodes, x, y, w, h} =>
if isCollidingPlus (iX, iY, iW, iH, x, y, w, h) then
let
val acc = helpGetCollisions (iX, iY, iW, iH, itemID, acc, topLeft)
val acc =
helpGetCollisions (iX, iY, iW, iH, itemID, acc, Vector.sub (nodes, tlIdx))
val acc = helpGetCollisions (iX, iY, iW, iH, itemID, acc, topRight)
val acc =
helpGetCollisions (iX, iY, iW, iH, itemID, acc, Vector.sub (nodes, trIdx))
val acc = helpGetCollisions
(iX, iY, iW, iH, itemID, acc, bottomLeft)
val acc =
helpGetCollisions (iX, iY, iW, iH, itemID, acc, Vector.sub (nodes, blIdx))
in
helpGetCollisions (iX, iY, iW, iH, itemID, acc, bottomRight)
helpGetCollisions
(iX, iY, iW, iH, itemID, acc, Vector.sub (nodes, brIdx))
end
else
acc
@@ -263,12 +263,12 @@ struct
fun hasCollisionAt (iX, iY, iW, iH, itemID, tree) =
case tree of
NODE {topLeft, topRight, bottomLeft, bottomRight, x, y, w, h} =>
NODE {nodes, x, y, w, h} =>
if isCollidingPlus (iX, iY, iW, iH, x, y, w, h) then
hasCollisionAt (iX, iY, iW, iH, itemID, topLeft)
orelse hasCollisionAt (iX, iY, iW, iH, itemID, topRight)
orelse hasCollisionAt (iX, iY, iW, iH, itemID, bottomLeft)
orelse hasCollisionAt (iX, iY, iW, iH, itemID, bottomRight)
hasCollisionAt (iX, iY, iW, iH, itemID, Vector.sub (nodes, tlIdx))
orelse hasCollisionAt (iX, iY, iW, iH, itemID, Vector.sub (nodes, trIdx))
orelse hasCollisionAt (iX, iY, iW, iH, itemID, Vector.sub (nodes, blIdx))
orelse hasCollisionAt (iX, iY, iW, iH, itemID, Vector.sub (nodes, brIdx))
else
false
| LEAF {items, x, y, w, h} =>
@@ -290,13 +290,13 @@ struct
fun getItemID (iX, iY, iW, iH, tree) =
case tree of
NODE {topLeft, topRight, bottomLeft, bottomRight, x, y, w, h} =>
NODE {nodes, x, y, w, h} =>
if isCollidingPlus (iX, iY, iW, iH, x, y, w, h) then
let
val try1 = getItemID (iX, iY, iW, iH, topLeft)
val try2 = getItemID (iX, iY, iW, iH, topRight)
val try3 = getItemID (iX, iY, iW, iH, bottomLeft)
val try4 = getItemID (iX, iY, iW, iH, bottomRight)
val try1 = getItemID (iX, iY, iW, iH, Vector.sub (nodes, tlIdx))
val try2 = getItemID (iX, iY, iW, iH, Vector.sub (nodes, trIdx))
val try3 = getItemID (iX, iY, iW, iH, Vector.sub (nodes, blIdx))
val try4 = getItemID (iX, iY, iW, iH, Vector.sub (nodes, brIdx))
(* get max: we assume query was narrow enough
* that only one ID is valid *)