First working version of hot-reloading feature

build.sh

@@ -11,28 +11,47 @@ VERSION="dev-$(date -u '+%Y-%m-%d')-$(git rev-parse --short HEAD)"
 ./scripts/wgpu-init.sh
 
 # ------------------------------------------
+# Game compile
 
 mkdir -p build
 
 # Game.dll
 odin build game/ -show-timings \
-    -collection:sindri=src \
-    -build-mode:dynamic \
-    -out:build/game -microarch:native -define:VERSION="$VERSION-debug" -debug "$@"
+	-collection:sindri=src \
+	-build-mode:dynamic \
+	-out:build/game_tmp -microarch:native -define:VERSION="$VERSION-debug" -debug "$@"
+
+# Need to use a temp file on Linux/macOS because it first writes an empty file,
+# which the engine will load before it is actually fully written.
+[ "$(uname -s)" = "Darwin" ] && LIB_EXT="dylib" || LIB_EXT="so"
+[ -f "build/game_tmp.$LIB_EXT" ] || {
+	echo "error: build produced no game lib.$LIB_EXT" >&2
+	exit 1
+}
+mv -f "build/game_tmp.$LIB_EXT" "build/game.$LIB_EXT"
+
+# ------------------------------------------
+# Engine compile
+
+# If the executable is already running, then don't try to build and start it.
+if pgrep -x $PROJECT >/dev/null; then
+	echo "Hot reloading..."
+	exit 0
+fi
 
 if [ "$1" = "debug" ]; then
-    shift
+	shift
 
-    odin build src/ -show-timings \
-        -collection:sindri=src \
-        -collection:gram=vendor/gram/src \
-        -collection:wgpu=vendor \
-        -out:build/$PROJECT -microarch:native -use-separate-modules -define:VERSION="$VERSION-debug" -debug "$@"
-    exit 0
+	odin build src/ -show-timings \
+		-collection:sindri=src \
+		-collection:gram=vendor/gram/src \
+		-collection:wgpu=vendor \
+		-out:build/$PROJECT -microarch:native -use-separate-modules -define:VERSION="$VERSION-debug" -debug "$@"
+	exit 0
 fi
 
 odin build src/ -show-timings \
-    -collection:sindri=src \
-    -collection:gram=vendor/gram/src \
-    -collection:wgpu=vendor \
-    -out:build/$PROJECT -microarch:native -o:speed -define:VERSION="$VERSION" "$@"
+	-collection:sindri=src \
+	-collection:gram=vendor/gram/src \
+	-collection:wgpu=vendor \
+	-out:build/$PROJECT -microarch:native -o:speed -define:VERSION="$VERSION" "$@"