Refactoring.

Consolidate hitBall() and throwBall() into one function.
Pull playerImage into its own "blipper" in utils.lua. This is definitely overkill, but we're learning with Lua, and it's fine, and it's very fine.

src/main.lua

@@ -1,3 +1,4 @@
+import 'CoreLibs/animation.lua'
 import 'CoreLibs/animator.lua'
 import 'CoreLibs/easing.lua'
 import 'CoreLibs/graphics.lua'
@@ -11,11 +12,12 @@ gfx.setBackgroundColor(gfx.kColorWhite)
 playdate.setMenuImage(gfx.image.new("images/game/menu-image.png"))
 
 local grassBackground = gfx.image.new("images/game/grass.png")
-local playerHighHat = gfx.image.new("images/game/player.png")
-local playerLowHat = gfx.image.new("images/game/player-lowhat.png")
-local playerImage = playerHighHat
-local secPerFrame = 0.1
-local playerFrameElapsed = 0
+
+local playerImageBlipper = blipper.new(
+        100,
+    "images/game/player.png",
+    "images/game/player-lowhat.png"
+)
 
 local backgroundPan = {
     x = 0,
@@ -64,8 +66,13 @@ local bases = {
     home = { x = screenW * 0.474, y = screenH * 0.79 }
 }
 
+local fielderSpeed = 40
 local fielders = {
-    first = {},
+    first = {
+        x = nil,
+        y = nil,
+        covering = nil -- TODO?
+    },
     second = {},
     shortstop = {},
     third = {},
@@ -100,17 +107,13 @@ local player = {
 
 local runners = { }
 
-function hitBall(destX, destY, hitFlyTime)
-    ballSizeAnimator:reset(ballSizeMs)
-    hitAnimatorY = gfx.animator.new(hitFlyTime, ballY, destY, playdate.easingFunctions.outQuint)
-    hitAnimatorX = gfx.animator.new(hitFlyTime, ballX, destX, playdate.easingFunctions.outQuint)
-end
-
-function throwBall(destX, destY)
-    local throwFlyTime = distanceBetween(ballX, ballY, destX, destY) * 5
-    ballSizeAnimator:reset(throwFlyTime)
-    hitAnimatorY = gfx.animator.new(throwFlyTime, ballY, destY, playdate.easingFunctions.linear)
-    hitAnimatorX = gfx.animator.new(throwFlyTime, ballX, destX, playdate.easingFunctions.linear)
+function throwBall(destX, destY, easingFunc, flyTimeMs)
+    if not flyTimeMs then
+        flyTimeMs = distanceBetween(ballX, ballY, destX, destY) * 5
+    end
+    ballSizeAnimator:reset(flyTimeMs)
+    hitAnimatorY = gfx.animator.new(flyTimeMs, ballY, destY, easingFunc)
+    hitAnimatorX = gfx.animator.new(flyTimeMs, ballX, destX, easingFunc)
 end
 
 function pitch()
@@ -159,8 +162,7 @@ function updateInfield()
         return
     end
 
-    local fielderSpeed = 40
-    for title,fielder in pairs(fielders) do
+    for _,fielder in pairs(fielders) do
         if fielder.targetX ~= nil and fielder.targetY ~= nil then
             local x, y, distance = normalizeVector(fielder.x, fielder.y, fielder.targetX, fielder.targetY)
 
@@ -266,6 +268,7 @@ function updateGameState()
     crankChange, acceleratedChange = playdate.getCrankChange()
     if currentMode == MODES.batting and acceleratedChange >= 0 and
       pointDirectlyUnderLine(ballX, ballY, batBaseX, batBaseY, batTipX, batTipY, screenH) then
+        currentMode = MODES.running
         ballAngle = batAngle + math.rad(90)
 
         mult = math.abs(acceleratedChange / 15)
@@ -277,17 +280,17 @@ function updateGameState()
         end
         ballDestX = ballX + (ballVelX * hitMult)
         ballDestY = ballY + (ballVelY * hitMult)
-        hitBall(ballDestX, ballDestY, 2000)
+        throwBall(ballDestX, ballDestY, playdate.easingFunctions.outQuint, 2000)
         local chasingFielder = getNearestFielder(ballDestX, ballDestY)
         chasingFielder.targetX = ballDestX
         chasingFielder.targetY = ballDestY
         chasingFielder.onArrive = function()
-            throwBall(getNextThrowTarget())
+            local targetX, targetY = getNextThrowTarget()
+            throwBall(targetX, targetY, playdate.easingFunctions.linear)
             chasingFielder.onArrive = nil
         end
         fielders.first.targetX = bases.first.x
         fielders.first.targetY = bases.first.y
-        currentMode = MODES.running
         player.nextBase = bases.first
         runners[#runners+1] = player
     end
@@ -316,6 +319,7 @@ end
 
 function playdate.update()
     updateGameState()
+    playdate.graphics.animation.blinker.updateAll()
 
     gfx.clear()
     grassBackground:draw(backgroundPan.x - 400, backgroundPan.y - 240)
@@ -324,7 +328,7 @@ function playdate.update()
     gfx.setLineWidth(2)
     gfx.drawCircleAtPoint(ballX + backgroundPan.x, ballY + backgroundPan.y, ballSize)
 
-    for title,fielder in pairs(fielders) do
+    for _,fielder in pairs(fielders) do
         gfx.fillRect(fielder.x + backgroundPan.x, fielder.y + backgroundPan.y, 14, 25)
     end
 
@@ -337,23 +341,15 @@ function playdate.update()
         )
     end
 
-    if playdate.isCrankDocked() then
+    if playdate.isCrankDocked() or (crankChange < 2 and currentMode == MODES.running) then
         playdate.ui.crankIndicator:draw()
     end
 
-    playerImage:draw(player.x + backgroundPan.x, player.y + backgroundPan.y)
-
-    -- TODO: Use gfx.animation.blinker instead
-    if currentMode == MODES.running and playerFrameElapsed > secPerFrame then
-        playerFrameElapsed = 0
-        if playerImage == playerHighHat then
-            playerImage = playerLowHat
-        else
-            playerImage = playerHighHat
-        end
-    else
-        playerFrameElapsed += deltaTime
-    end
+    playerImageBlipper:draw(
+            currentMode ~= MODES.running,
+        player.x + backgroundPan.x,
+        player.y + backgroundPan.y
+    )
 
     -- for i,runner in pairs(runners) do
     --     playerImage:draw(runner.x, runner.y)

src/utils.lua

@@ -1,3 +1,6 @@
+import 'CoreLibs/animation.lua'
+import 'CoreLibs/graphics.lua'
+
 --- Returns the normalized vector as two values, plus the distance between the given points.
 function normalizeVector(x1, y1, x2, y2)
     local distance, a, b = distanceBetween(x1, y1, x2, y2)
@@ -29,3 +32,20 @@ function pointDirectlyUnderLine(pointX, pointY, lineX1, lineY1, lineX2, lineY2,
     return yDelta <= 0
 end
 
+blipper = {
+    --- Build an object that simply "blips" between the given images at the given interval.
+    --- Expects `playdate.graphics.animation.blinker.updateAll()` to be called on every update.
+    new = function(msInterval, imagePath1, imagePath2)
+        local blinker = playdate.graphics.animation.blinker.new(msInterval, msInterval, true)
+        blinker:start()
+        return {
+            blinker = blinker,
+            image1 = playdate.graphics.image.new(imagePath1),
+            image2 = playdate.graphics.image.new(imagePath2),
+            draw = function(self, disableBlipping, x, y)
+                local currentImage = (disableBlipping or self.blinker.on) and self.image2 or self.image1
+                currentImage:draw(x, y)
+            end
+        }
+    end
+}