Fix lack of hand when spectating player in replay on 1.13+

src/main/java/com/replaymod/replay/mixin/MixinGameRenderer.java

@@ -0,0 +1,36 @@
+//#if MC>=11300
+package com.replaymod.replay.mixin;
+
+import com.replaymod.replay.camera.CameraEntity;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.network.ClientPlayerEntity;
+import net.minecraft.client.network.ClientPlayerInteractionManager;
+import net.minecraft.client.render.GameRenderer;
+import net.minecraft.world.GameMode;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Accessor;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+@Mixin(GameRenderer.class)
+public abstract class MixinGameRenderer {
+    @Accessor
+    abstract MinecraftClient getClient();
+
+    @Redirect(
+            method = "renderHand",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/client/network/ClientPlayerInteractionManager;getCurrentGameMode()Lnet/minecraft/world/GameMode;"
+            )
+    )
+    private GameMode getGameMode(ClientPlayerInteractionManager interactionManager) {
+        ClientPlayerEntity camera = getClient().player;
+        if (camera instanceof CameraEntity) {
+            // alternative doesn't really matter, the caller only checks for equality to SPECTATOR
+            return camera.isSpectator() ? GameMode.SPECTATOR : GameMode.SURVIVAL;
+        }
+        return interactionManager.getCurrentGameMode();
+    }
+}
+//#endif