Bomberman movement cleanup, notes on pacman movement

game/entities/bomberman.fnl

@@ -35,31 +35,32 @@
 ; * if there is one solid and one empty tile in front of Bomberman, push Bomberman
 ;   back onto the tile boundary, and push Bomberman towards the empty tile in the
 ;   other axis
-; repeat for both x and y axis
-; TODO: do we add the two vectors? is it acceptable that diagonal movement is faster?
-(fn horizontal [x y] (fn [dx dy] [(+ x dx) (+ y dy)]))
-(fn vertical [x y]   (fn [dy dx] [(+ x dx) (+ y dy)]))
-(fn bomberman.axis-movement [off c copp dc rules]
-  (let [d (fn [cnew] (- cnew c))
-       (edge-prev edge-next) (edge c dc dim.halftile)
+; Movement only happens along one axis; diagonal movement is not allowed.
+(fn horizontal [c copp] [c copp])
+(fn vertical   [c copp] [copp c])
+(fn bomberman.axis-movement [make-xy c copp dc rules]
+  (let [(edge-prev edge-next) (edge c dc dim.halftile)
         crosses (edge-crosses edge-prev edge-next dim.tilesize)
-        neg-collides (bomberman.collides? (off (d edge-next) (- dim.halftile)) rules)
-        pos-collides (bomberman.collides? (off (d edge-next) (- dim.halftile 0.01)) rules)
-        dc-edge (d (bomberman.tile-edge edge-next dc))
-        dcopp (math.abs dc)]
-    (if (not crosses) [dc 0]
-        (and (not neg-collides) (not pos-collides)) [dc 0]
-        (and neg-collides pos-collides) [dc-edge 0]
-        neg-collides [dc-edge (math.min dcopp (- (bomberman.tile-edge (+ copp dim.tilesize (- dim.halftile 0.01)) 1) copp))]
-        pos-collides [dc-edge (math.max (- dcopp) (- (bomberman.tile-edge (- copp dim.tilesize dim.halftile) -1) copp))])))
+        neg-edge (- copp dim.halftile)
+        neg-collides (bomberman.collides? (make-xy edge-next neg-edge) rules)
+        pos-edge (+ copp dim.halftile -0.01)
+        pos-collides (bomberman.collides? (make-xy edge-next pos-edge) rules)
+        dc-edge (- (bomberman.tile-edge edge-next dc) c)
+        dcopp (math.abs dc)
+        [cn coppn]
+        (if (not crosses) [dc 0]
+            (and (not neg-collides) (not pos-collides)) [dc 0]
+            (and neg-collides pos-collides) [dc-edge 0]
+            neg-collides [dc-edge (math.min dcopp (- (bomberman.tile-edge (+ pos-edge dim.tilesize) 1) copp))]
+            pos-collides [dc-edge (math.max (- dcopp) (- (bomberman.tile-edge (- neg-edge dim.tilesize) -1) copp))])]
+    (make-xy cn coppn)))
 
 (fn bomberman.update [entity dt rules]
   (set entity.vel (direct bomberman.keymap (* dim.tilesize 3)))
   (let [[x y] entity.pos
         [dx dy] (vec* entity.vel dt)
-        [dx1 dy1] (bomberman.axis-movement (horizontal x y) x y dx rules)
-        [dy2 dx2] (bomberman.axis-movement (vertical x y) y x dy rules)
-        [dx dy] (if (not= dx 0) [dx1 dy1] [dx2 dy2])]
+        [dx dy] (if (not= dx 0) (bomberman.axis-movement horizontal x y dx rules)
+                                (bomberman.axis-movement vertical y x dy rules))]
     (set entity.pos [(+ x dx) (+ y dy)]))
   (when (love.keyboard.isDown bomberman.keymap.bomb)
     (rules.place-bomb (map.world-to-tile entity.pos))))

game/entities/pacman.fnl

@@ -1,9 +1,23 @@
-(local Entity (require :game.entity))
-(local rules (require :game.rules))
+(local util (require :lib.util))
+(local dim (require :game.dim))
 
-(local Pacman (Entity:extend))
-(set Pacman.keymap {:up :up :down :down :left :left :right :right})
-(set Pacman.color [1 1 0])
+(local map (require :game.tilemap))
 
-Pacman
+(local pacman (util.hot-table ...))
 
+; Pacman movement and collision rules
+; * Pacman moves in the direction he was told until stopped by a wall
+; * If the player tells Pacman to change direction but there is a wall there,
+;   Pacman's direction does not change
+; * Turning a corner is funky:
+; https://www.gamasutra.com/view/feature/132330/the_pacman_dossier.php?page=4
+; "Whenever Pac-Man makes a pre-turn or post-turn, his orientation changes, and he starts to
+;  move one pixel in his new direction for every pixel traveled in his old direction, effectively
+;  doubling his speed as he moves at a 45 degree angle. Once he reaches the centerline of the new
+;  direction's path, he starts moving purely in that direction and his speed returns to normal."
+; The simplest way to implement this appears to be to treat turns as having a "fudge factor" -
+; Pacman enters a state where he changes direction _and_ is being pulled towards the center of
+; the track. (The "post-turn" correction means we can't simply treat this as the corners having
+; their edges filed off!)
+; I think Bomberman actually does this too
+pacman.hot