Initial commit

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-11-08 01:30:33 -05:00
commit 2007fb7edc
@@ -0,0 +1,84 @@
+#!/usr/bin/env bash
+# Checks the simulation is deterministic across builds and platforms, which desktop/web crossplay depends on.
+#
+# Fails if any source calls the maths library's transcendentals (src/dmath.h replaces them), then builds the game
+# several ways and plays the same seeded bot matches in each (--balance with RPG_SEED), comparing the determinism hash
+# they print:
+#   gcc        GCC, optimised (the usual build)
+#   gcc-fma    GCC for this CPU (with FMA if it has it, standing in for arm64's fused multiply-adds)
+#   clang-O0   Clang, unoptimised
+#   wasm       Emscripten, run under node (needs EMSDK, or emsdk_env.sh sourced)
+#
+# Usage: tools/determinism_check.sh [matches per seed, default 20] [seeds, default "1 2 3"]
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+OUT="$ROOT/build-check"
+MATCHES="${1:-20}"
+SEEDS="${2:-1 2 3}"
+
+banned=$(grep -nE "std::(sin|cos|tan|atan2|atan|asin|acos|exp|exp2|expm1|log|log2|log10|log1p|pow|hypot|cbrt|sinh|cosh|tanh|lerp)\(|\b(sinf|cosf|tanf|atan2f|powf|expf|logf|log2f)\(|SDL_(sin|cos|tan|atan2|atan|pow|exp|log)f?\(" \
+    "$ROOT"/src/*.cpp "$ROOT"/src/*.h | grep -v "src/dmath.h" || true)
+if [ -n "$banned" ]; then
+    echo "Maths library transcendentals in the source (use math_sin and friends from src/dmath.h):"
+    echo "$banned"
+    exit 1
+fi
+
+configure() # name, cmake arguments...
+{
+    local name="$1"
+    shift
+    if [ ! -f "$OUT/$name/build.ninja" ]; then
+        cmake -S "$ROOT" -B "$OUT/$name" -G Ninja "$@" > "$OUT/$name.log" 2>&1
+    fi
+    cmake --build "$OUT/$name" >> "$OUT/$name.log" 2>&1 || {
+        echo "$name failed to build, see $OUT/$name.log"
+        exit 1
+    }
+}
+
+mkdir -p "$OUT"
+names=(gcc gcc-fma clang-O0)
+configure gcc -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++
+configure gcc-fma -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ \
+    -DCMAKE_CXX_FLAGS=-march=native -DCMAKE_C_FLAGS=-march=native
+configure clang-O0 -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
+if [ -n "${EMSDK:-}" ] || command -v emcmake > /dev/null; then
+    [ -n "${EMSDK:-}" ] && source "$EMSDK/emsdk_env.sh" > /dev/null 2>&1
+    if [ ! -f "$OUT/wasm/build.ninja" ]; then
+        emcmake cmake -S "$ROOT" -B "$OUT/wasm" -G Ninja -DCMAKE_BUILD_TYPE=Release -DRPG_NODE=ON > "$OUT/wasm.log" 2>&1
+    fi
+    cmake --build "$OUT/wasm" >> "$OUT/wasm.log" 2>&1 || {
+        echo "wasm failed to build, see $OUT/wasm.log"
+        exit 1
+    }
+    names+=(wasm)
+else
+    echo "Emscripten not found (set EMSDK): skipping the wasm build."
+fi
+
+hash_get() # name, seed
+{
+    local run=("$OUT/$1/smack-a-brother")
+    [ "$1" = wasm ] && run=(node "$OUT/wasm/smack-a-brother.js")
+    (cd "$OUT/$1" && RPG_SEED="$2" "${run[@]}" --balance "$MATCHES" 2>&1 | grep -oE "hash: [0-9a-f]+" | cut -d' ' -f2)
+}
+
+failed=0
+for seed in $SEEDS; do
+    line="seed $seed:"
+    first=""
+    for name in "${names[@]}"; do
+        hash=$(hash_get "$name" "$seed")
+        line+="  $name $hash"
+        [ -z "$first" ] && first="$hash"
+        [ "$hash" != "$first" ] && failed=1
+    done
+    echo "$line"
+done
+if [ "$failed" = 1 ]; then
+    echo "DESYNC: the builds disagree."
+    exit 1
+fi
+echo "Deterministic: every build agrees."