Async logic framework, box2D dependencies

core/src/mindustry/async/AsyncLogic.java

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+package mindustry.async;
+
+import arc.struct.*;
+
+import java.util.concurrent.*;
+
+public class AsyncLogic{
+    //all processes to be executed each frame
+    private Array<AsyncProcess> processes = Array.with(new PhysicsProcess());
+
+    //futures to be awaited
+    private Array<Future<?>> futures = new Array<>();
+
+    private ExecutorService executor = Executors.newFixedThreadPool(processes.size, r -> {
+        Thread thread = new Thread(r, "AsyncExecutor-Thread");
+        thread.setDaemon(true);
+        thread.setUncaughtExceptionHandler((t, e) -> {
+            e.printStackTrace();
+            //TODO crash!
+        });
+        return thread;
+    });
+
+    public void begin(){
+        //sync begin
+        for(AsyncProcess p : processes){
+            p.begin();
+        }
+
+        futures.clear();
+
+        //submit all tasks
+        for(AsyncProcess p : processes){
+            futures.add(executor.submit(p::process));
+        }
+    }
+
+    public void end(){
+        //wait for all threads to stop processing
+        for(Future future : futures){
+            try{
+                future.get();
+            }catch(Throwable t){
+                throw new RuntimeException(t);
+            }
+        }
+
+        futures.clear();
+
+        //sync end (flush data)
+        for(AsyncProcess p : processes){
+            p.end();
+        }
+    }
+}

core/src/mindustry/async/AsyncProcess.java

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+package mindustry.async;
+
+public interface AsyncProcess{
+
+    /** Synchronous. Called at the beginning of the main loop. */
+    void begin();
+
+    /** Async. Called in a separate thread. */
+    void process();
+
+    /** Sync. Called in the end of the main loop. */
+    void end();
+}

core/src/mindustry/async/PhysicsProcess.java

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+package mindustry.async;
+
+public class PhysicsProcess implements AsyncProcess{
+
+    @Override
+    public void begin(){
+
+    }
+
+    @Override
+    public void process(){
+
+    }
+
+    @Override
+    public void end(){
+
+    }
+}