feat(ModularBot): displacement-vector gun, 11 guns total

- Displacement gun: average velocity over sliding window, captures drift
- Complements instantaneous-velocity linear gun
- Battle-tested vs Crazy, WaveSurfer, PatternMover

ModularBot_garage/src/ModularBot.nim

@@ -20,12 +20,13 @@ import guns/anti_surfer
 import guns/wall_bounce
 import guns/accel_predictor
 import guns/stop_shot
+import guns/displacement
 import movements/phantom_meteor
 
 const botJsonPath = currentSourcePath().parentDir / "ModularBot.json"
 const DebugVBullets = false
 const DebugCircular = false
-const GunNames = ["HeadOn", "Linear", "Tsetlin", "Circular", "GuessFactor", "Pattern", "AntiSurf", "WallBounce", "Accel", "StopShot"]
+const GunNames = ["HeadOn", "Linear", "Tsetlin", "Circular", "GuessFactor", "Pattern", "AntiSurf", "WallBounce", "Accel", "StopShot", "Displace"]
 
 type
   ModularBot = ref object of Bot
@@ -44,6 +45,7 @@ type
     wallBounce:   WallBounceGun
     accelGun:     AccelGun
     stopShot:     StopShotGun
+    displace:     DisplacementGun
     mover:        PhantomMeteorModule
     virtualHits:  int
     virtualMiss:  int
@@ -84,6 +86,7 @@ method onScannedBot*(bot: ModularBot, e: ScannedBotEvent) =
   var wbPreds:   array[len(PowerBins), GunPrediction]
   var acPreds:   array[len(PowerBins), GunPrediction]
   var ssPreds:   array[len(PowerBins), GunPrediction]
+  var dsPreds:   array[len(PowerBins), GunPrediction]
   for i in 0..<len(PowerBins):
     headsUp[i]   = bot.headOn.predict(bot.lastState, bulletSpeed(PowerBins[i]))
     linPreds[i]  = bot.linear.predict(bot.lastState, bulletSpeed(PowerBins[i]))
@@ -95,6 +98,7 @@ method onScannedBot*(bot: ModularBot, e: ScannedBotEvent) =
     wbPreds[i]   = bot.wallBounce.predict(bot.lastState, bulletSpeed(PowerBins[i]))
     acPreds[i]   = bot.accelGun.predict(bot.lastState, bulletSpeed(PowerBins[i]))
     ssPreds[i]   = bot.stopShot.predict(bot.lastState, bulletSpeed(PowerBins[i]))
+    dsPreds[i]   = bot.displace.predict(bot.lastState, bulletSpeed(PowerBins[i]))
 
   bot.tracker.spawnBullets(0, headsUp,   bot.lastState)
   bot.tracker.spawnBullets(1, linPreds,  bot.lastState)
@@ -108,6 +112,7 @@ method onScannedBot*(bot: ModularBot, e: ScannedBotEvent) =
   bot.tracker.spawnBullets(7, wbPreds,   bot.lastState)
   bot.tracker.spawnBullets(8, acPreds,   bot.lastState)
   bot.tracker.spawnBullets(9, ssPreds,   bot.lastState)
+  bot.tracker.spawnBullets(10, dsPreds,  bot.lastState)
 
   # Resolve bullets that have travelled far enough
   let st = bot.lastState
@@ -128,6 +133,7 @@ method onScannedBot*(bot: ModularBot, e: ScannedBotEvent) =
     of 7: bot.wallBounce.onResult(fe)
     of 8: bot.accelGun.onResult(fe)
     of 9: bot.stopShot.onResult(fe)
+    of 10: bot.displace.onResult(fe)
     else: discard
     if fe.hit: inc bot.virtualHits else: inc bot.virtualMiss
     when DebugVBullets:
@@ -154,6 +160,7 @@ method onScannedBot*(bot: ModularBot, e: ScannedBotEvent) =
     of 7: setTurretColor("#CCCCCC"); setBulletColor("#EEEEEE")  # WallBounce: silver/white
     of 8: setTurretColor("#FF00FF"); setBulletColor("#FF66FF")  # Accel: magenta
     of 9: setTurretColor("#990000"); setBulletColor("#CC3333")  # StopShot: dark red
+    of 10: setTurretColor("#006600"); setBulletColor("#009900") # Displace: dark green
     else: discard
 
   let pred = case selectedGun
@@ -166,6 +173,7 @@ method onScannedBot*(bot: ModularBot, e: ScannedBotEvent) =
     of 7: bot.wallBounce.predict(bot.lastState, bulletSpeed(power))
     of 8: bot.accelGun.predict(bot.lastState, bulletSpeed(power))
     of 9: bot.stopShot.predict(bot.lastState, bulletSpeed(power))
+    of 10: bot.displace.predict(bot.lastState, bulletSpeed(power))
     else: bot.headOn.predict(bot.lastState, bulletSpeed(power))
   let target = aimAngle(getX(), getY(), pred.x, pred.y)
 
@@ -225,7 +233,7 @@ method run*(bot: ModularBot) =
 
 when isMainModule:
   var bot = ModularBot(
-    tracker:    vb.initTracker(10),  # 0: HeadOn, 1: Linear, 2: Tsetlin, 3: Circular, 4: GuessFactor, 5: Pattern, 6: AntiSurf, 7: WallBounce, 8: Accel, 9: StopShot
+    tracker:    vb.initTracker(11),  # 0: HeadOn, 1: Linear, 2: Tsetlin, 3: Circular, 4: GuessFactor, 5: Pattern, 6: AntiSurf, 7: WallBounce, 8: Accel, 9: StopShot, 10: Displace
     headOn:     HeadOnGun(),
     linear:     LinearGun(),
     circular:   CircularGun(),
@@ -236,6 +244,7 @@ when isMainModule:
     wallBounce:  initWallBounceGun(),
     accelGun:    initAccelGun(),
     stopShot:    initStopShotGun(),
+    displace:    initDisplacementGun(),
     radar:      RadarLockModule(),
     mover:      initPhantomMeteor(),
     currentGun: -1,

common_libs/guns/displacement.nim

@@ -0,0 +1,65 @@
+## Displacement-vector gun: predict using average velocity over a sliding window.
+## Captures drift/tendency that instantaneous velocity misses
+## (e.g. oscillating enemy slowly drifting east has v=0 at midpoints but
+##  displacement still pointing east).
+
+import std/math
+import gun_harness/gun_interface
+
+const WindowSize = 15  # ticks; N+1 frames stored
+
+type
+  DisplacementGun* = object
+    posX:    array[WindowSize + 1, float]
+    posY:    array[WindowSize + 1, float]
+    count:   int   # frames collected so far
+    head:    int   # ring-buffer head
+    lastTick: int  # for per-tick cache
+    cacheSpeed: float
+    cachePred:  GunPrediction
+
+proc predict*(g: var DisplacementGun, state: WorldState, bulletSpeed: float): GunPrediction =
+  # Per-tick cache: same tick + same speed => same prediction
+  if state.tick == g.lastTick and bulletSpeed == g.cacheSpeed:
+    return g.cachePred
+
+  # Push current position into ring buffer
+  g.head = (g.head + 1) mod (WindowSize + 1)
+  g.posX[g.head] = state.enemyX
+  g.posY[g.head] = state.enemyY
+  if g.count < WindowSize + 1:
+    inc g.count
+
+  g.lastTick   = state.tick
+  g.cacheSpeed = bulletSpeed
+
+  # Need at least N+1 frames; fall back to head-on if not enough
+  if g.count < WindowSize + 1:
+    g.cachePred = GunPrediction(x: state.enemyX, y: state.enemyY)
+    return g.cachePred
+
+  # Oldest frame is (head + 1) mod (WindowSize + 1)
+  let oldest = (g.head + 1) mod (WindowSize + 1)
+  let dx = (state.enemyX - g.posX[oldest]) / WindowSize.float
+  let dy = (state.enemyY - g.posY[oldest]) / WindowSize.float
+
+  # Iterate time estimate 5 times
+  let dist0 = hypot(state.enemyX - state.selfX, state.enemyY - state.selfY)
+  var ticks = dist0 / bulletSpeed
+  var px = state.enemyX
+  var py = state.enemyY
+  for _ in 0..4:
+    px = state.enemyX + dx * ticks
+    py = state.enemyY + dy * ticks
+    ticks = hypot(px - state.selfX, py - state.selfY) / bulletSpeed
+
+  px = clamp(px, 0.0, state.arenaWidth)
+  py = clamp(py, 0.0, state.arenaHeight)
+  g.cachePred = GunPrediction(x: px, y: py)
+  g.cachePred
+
+proc onResult*(g: var DisplacementGun, e: FeedbackEvent) =
+  discard  # analytical gun — no learning
+
+proc initDisplacementGun*(): DisplacementGun =
+  DisplacementGun(count: 0, head: 0, lastTick: -1)