Closes #919, closes #982, closes #1003, closes #1012, closes #1022, closes #1028, closes #1033

src/ui/EvolutionState.lua

@@ -46,9 +46,27 @@ function EvolutionState:sgbPalettes(game)
   return P.wholeNamed(game.data, "MEWMON")
 end
 
-local FLASH_FRAMES = 220
 -- evolution.asm EvolveMon delays 80 frames before .animLoop, polling nothing (#968, #1031)
 local CANCEL_GRACE_FRAMES = 80
+-- .animLoop starts at `lb bc, $1, $10` and runs 8 iterations: iteration k holds
+-- the old pic for c = 18-2k frames inside Evolution_CheckForCancel (72 in all),
+-- then Evolution_BackAndForthAnim swaps b = k times, each swap a pair of
+-- Evolution_ChangeMonPic that end in Delay3 (6 frames a swap, 216 in all).
+local ANIM_LOOP_FRAMES = 288
+local FLASH_FRAMES = CANCEL_GRACE_FRAMES + ANIM_LOOP_FRAMES
+
+-- which pic is on screen t frames into .animLoop
+local function evoShowsNew(t)
+  for b = 1, 8 do
+    local hold = 18 - 2 * b
+    if t < hold then return false end
+    t = t - hold
+    local swap = b * 6
+    if t < swap then return t % 6 < 3 end
+    t = t - swap
+  end
+  return true
+end
 
 local function frontSprite(game, species, mon)
   local path, trueColor = require("src.pokemon.Sprites").path(
@@ -140,14 +158,10 @@ function EvolutionState:draw()
     else
       sprite, spriteTrueColor = self.newSprite, self.newSpriteTrueColor
     end
+  elseif evoShowsNew(self.t - CANCEL_GRACE_FRAMES) then
+    sprite, spriteTrueColor = self.newSprite, self.newSpriteTrueColor
   else
-    local period = math.max(4, 28 - math.floor(self.t / 40) * 6)
-    local showNew = math.floor(self.t / period) % 2 == 1
-    if showNew then
-      sprite, spriteTrueColor = self.newSprite, self.newSpriteTrueColor
-    else
-      sprite, spriteTrueColor = self.oldSprite, self.oldSpriteTrueColor
-    end
+    sprite, spriteTrueColor = self.oldSprite, self.oldSpriteTrueColor
   end
   if sprite then
     local x = math.floor((160 - sprite:getWidth()) / 2)