Files
SirRoboGarage/common_libs/guns/knn_gun.nim
T
SirStone 2cc2a3bd87 fix(ModularBot): ram loop prevention, dead-target guards, cleaner logging
- 30-tick cooldown after ghost-stuck/timeout ram exit prevents re-entry loop
- enemy_tracker.update() skips dead bots to prevent same-tick scan resurrection
- TFIL graphics cleared when ramming is active movement
- [config] logs: white base with green-highlighted changes only
- [ram:enter] logs trigger reason and key values on false→true transition
- [death] and [target-invalid] logs retained for diagnostics
2026-09-20 20:44:45 +02:00

262 lines
9.3 KiB
Nim

## KNN gun: K-nearest-neighbor statistical targeting inspired by DrussGT's DC gun.
## Builds a feature vector per scan, stores resolved GF outcomes, queries KNN at
## predict time and picks the GF with the highest Gaussian-weighted density.
## ponytail: linear scan O(n*k), cap at 2000 obs — KD-tree if perf matters at scale.
import std/[math]
import gun_harness/gun_interface
const
MaxObs = 2000 # ring-buffer cap
KCap = 50 # hard ceiling on K
KernelW = 0.3 # Gaussian kernel width multiplier
DensityBins = 60 # scan resolution for peak-GF search
type
Obs = object
feat: array[7, float] # normalized feature vector
gf: float # observed GF at wave resolution
KNNWave = object
fireX, fireY: float
fireBearing: float
feat: array[7, float]
KNNGun* = object
obs: seq[Obs]
obsHead: int # ring-buffer write index
waves: seq[KNNWave]
# per-tick cache
cachedTick: int
cachedWaveStored: bool
# rolling normalization ranges
featMin: array[7, float]
featMax: array[7, float]
# state for feature extraction
lastSpeed: float
lastDirection: float # +1 or -1
timeSinceDirChange: int
debugGraphics*: bool
proc initKNNGun*(): KNNGun =
result.cachedTick = -1
result.lastDirection = 1.0
result.debugGraphics = false
for i in 0..6:
result.featMin[i] = 1e18
result.featMax[i] = -1e18
# ── helpers ──────────────────────────────────────────────────────────────────
proc normFeat(g: KNNGun, raw: array[7, float]): array[7, float] =
for i in 0..6:
let span = g.featMax[i] - g.featMin[i]
result[i] = if span > 1e-9: (raw[i] - g.featMin[i]) / span else: 0.0
proc updateMinMax(g: var KNNGun, raw: array[7, float]) =
for i in 0..6:
if raw[i] < g.featMin[i]: g.featMin[i] = raw[i]
if raw[i] > g.featMax[i]: g.featMax[i] = raw[i]
proc buildFeatures(state: WorldState, lastSpeed, lastDir: float,
tsdc: int): array[7, float] =
let dx = state.enemyX - state.selfX
let dy = state.enemyY - state.selfY
let dist = sqrt(dx*dx + dy*dy)
let arenaDiag = sqrt(state.arenaWidth*state.arenaWidth + state.arenaHeight*state.arenaHeight)
# bearing to enemy (0°=East, standard Tank Royale)
let bearing = arctan2(dy, dx)
# angle of enemy heading relative to bearing
let relHead = state.enemyHeading - bearing
let latVel = state.enemySpeed * sin(relHead)
let advVel = state.enemySpeed * (-cos(relHead))
let accel = state.enemySpeed - lastSpeed # signed delta
# wall distances: how far enemy can travel fwd/bwd before hitting wall
# approximate: project enemy heading to nearest wall in each axis
let ex = state.enemyX
let ey = state.enemyY
let eh = state.enemyHeading
# forward distances to each wall in heading direction
let fwdX = if cos(eh) > 0: (state.arenaWidth - ex) / max(abs(cos(eh)), 1e-9)
else: ex / max(abs(cos(eh)), 1e-9)
let fwdY = if sin(eh) > 0: (state.arenaHeight - ey) / max(abs(sin(eh)), 1e-9)
else: ey / max(abs(sin(eh)), 1e-9)
let fwdDist = min(fwdX, fwdY)
# backward = forward in opposite direction
let bwdX = if cos(eh) < 0: (state.arenaWidth - ex) / max(abs(cos(eh)), 1e-9)
else: ex / max(abs(cos(eh)), 1e-9)
let bwdY = if sin(eh) < 0: (state.arenaHeight - ey) / max(abs(sin(eh)), 1e-9)
else: ey / max(abs(sin(eh)), 1e-9)
let bwdDist = min(bwdX, bwdY)
result[0] = abs(latVel) / 8.0
result[1] = clamp(advVel / 8.0, -1.0, 1.0) * 0.5 + 0.5 # shift to [0,1]
result[2] = clamp(dist / arenaDiag, 0.0, 1.0)
result[3] = clamp(accel / 2.0, -1.0, 1.0) * 0.5 + 0.5
result[4] = clamp(float(tsdc) / 100.0, 0.0, 1.0)
result[5] = clamp(fwdDist / arenaDiag, 0.0, 1.0)
result[6] = clamp(bwdDist / arenaDiag, 0.0, 1.0)
proc euclidean(a, b: array[7, float]): float {.inline.} =
for i in 0..6:
let d = a[i] - b[i]
result += d * d
result = sqrt(result)
# ── Gun interface ─────────────────────────────────────────────────────────────
proc predict*(g: var KNNGun, state: WorldState, bulletSpd: float): GunPrediction =
if bulletSpd <= 0.0:
return GunPrediction(x: state.enemyX, y: state.enemyY)
let dx = state.enemyX - state.selfX
let dy = state.enemyY - state.selfY
let dist = sqrt(dx*dx + dy*dy)
let bearing = arctan2(dy, dx)
let mea = arcsin(clamp(8.0 / bulletSpd, -1.0, 1.0))
# Track direction change — update state once per tick
if state.tick != g.cachedTick:
g.cachedTick = state.tick
g.cachedWaveStored = false
let relHead = state.enemyHeading - bearing
let latVel = state.enemySpeed * sin(relHead)
let newDir = if latVel >= 0: 1.0 else: -1.0
if newDir != g.lastDirection and abs(latVel) > 0.01:
g.timeSinceDirChange = 0
g.lastDirection = newDir
else:
inc g.timeSinceDirChange
# Store wave once per tick
if not g.cachedWaveStored:
let feat = buildFeatures(state, g.lastSpeed, g.lastDirection, g.timeSinceDirChange)
g.updateMinMax(feat)
g.waves.add KNNWave(
fireX: state.selfX,
fireY: state.selfY,
fireBearing: bearing,
feat: feat,
)
g.lastSpeed = state.enemySpeed
g.cachedWaveStored = true
# Cold start — no data yet
if g.obs.len == 0:
return GunPrediction(
x: clamp(state.selfX + cos(bearing) * dist, BotRadius, state.arenaWidth - BotRadius),
y: clamp(state.selfY + sin(bearing) * dist, BotRadius, state.arenaHeight - BotRadius),
)
# Build query feature vector (use current state)
let queryRaw = buildFeatures(state, g.lastSpeed, g.lastDirection, g.timeSinceDirChange)
let query = g.normFeat(queryRaw)
# KNN: linear scan, pick k = max(5, min(sqrt(n), KCap))
# Fall back to head-on when not enough neighbors to be meaningful
let n = g.obs.len
if n < 5:
return GunPrediction(
x: clamp(state.selfX + cos(bearing) * dist, BotRadius, state.arenaWidth - BotRadius),
y: clamp(state.selfY + sin(bearing) * dist, BotRadius, state.arenaHeight - BotRadius),
)
let k = max(5, min(int(sqrt(float(n))), KCap))
# Partial selection: maintain k-best by tracking max distance in result set
# ponytail: O(n*k) insertion; fine for n<=2000, k<=50
var bestDists = newSeq[float](k)
var bestGFs = newSeq[float](k)
var worstIdx = 0
var filled = 0
for i in 0..<n:
let normFeat = g.normFeat(g.obs[i].feat)
let d = euclidean(query, normFeat)
if filled < k:
bestDists[filled] = d
bestGFs[filled] = g.obs[i].gf
inc filled
if filled == k:
# find worst
worstIdx = 0
for j in 1..<k:
if bestDists[j] > bestDists[worstIdx]: worstIdx = j
elif d < bestDists[worstIdx]:
bestDists[worstIdx] = d
bestGFs[worstIdx] = g.obs[i].gf
worstIdx = 0
for j in 1..<k:
if bestDists[j] > bestDists[worstIdx]: worstIdx = j
if filled == 0:
return GunPrediction(
x: clamp(state.selfX + cos(bearing) * dist, BotRadius, state.arenaWidth - BotRadius),
y: clamp(state.selfY + sin(bearing) * dist, BotRadius, state.arenaHeight - BotRadius),
)
# Inverse-distance weights, Gaussian (same as DrussGT getBearingGaussian)
var sumDist = 1e-30
for i in 0..<filled: sumDist += bestDists[i]
let invAvg = float(filled) / sumDist
# Find GF range of neighbors
var gfMin = bestGFs[0]
var gfMax = bestGFs[0]
for i in 1..<filled:
if bestGFs[i] < gfMin: gfMin = bestGFs[i]
if bestGFs[i] > gfMax: gfMax = bestGFs[i]
# Scan DensityBins points in [gfMin, gfMax] for peak density
let span = max(gfMax - gfMin, 1e-9)
let step = span / float(DensityBins - 1)
var bestGF = gfMin
var bestScore = -1.0
for b in 0..<DensityBins:
let testGF = gfMin + float(b) * step
var score = 0.0
for i in 0..<filled:
let w = exp(-0.5 * (bestDists[i] * invAvg) * (bestDists[i] * invAvg))
let dg = (testGF - bestGFs[i]) / max(span * KernelW, 1e-9)
score += w * exp(-0.5 * dg * dg)
if score > bestScore:
bestScore = score
bestGF = testGF
let aimAngle = bearing + clamp(bestGF, -1.0, 1.0) * mea
let px = state.selfX + cos(aimAngle) * dist
let py = state.selfY + sin(aimAngle) * dist
GunPrediction(
x: clamp(px, BotRadius, state.arenaWidth - BotRadius),
y: clamp(py, BotRadius, state.arenaHeight - BotRadius),
)
proc onResult*(g: var KNNGun, e: FeedbackEvent) =
if g.waves.len == 0: return
let w = g.waves[0]
g.waves.delete(0)
let speed = bulletSpeed(e.bulletPower)
let mea = arcsin(clamp(8.0 / speed, -1.0, 1.0))
let ax = e.actualX - w.fireX
let ay = e.actualY - w.fireY
var delta = arctan2(ay, ax) - w.fireBearing
while delta > PI: delta -= 2.0 * PI
while delta < -PI: delta += 2.0 * PI
let gf = if mea > 1e-10: clamp(delta / mea, -1.0, 1.0) else: 0.0
g.updateMinMax(w.feat)
if g.obs.len < MaxObs:
g.obs.add Obs(feat: w.feat, gf: gf)
else:
# ring buffer
g.obs[g.obsHead] = Obs(feat: w.feat, gf: gf)
g.obsHead = (g.obsHead + 1) mod MaxObs