WIP decoupled rendering

README.md

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+## Physics and Timing
+
+I want to have decoupled rendering with the ability to render partial physics simulations, so it needs to be deterministic.
+
+Based on this snippet from [this article](https://gafferongames.com/post/fix_your_timestep/)
+
+```c
+double t = 0.0;
+double dt = 0.01;
+
+double currentTime = hires_time_in_seconds();
+double accumulator = 0.0;
+
+State previous;
+State current;
+
+while ( !quit )
+{
+    double newTime = time();
+    double frameTime = newTime - currentTime;
+    if ( frameTime > 0.25 )
+        frameTime = 0.25;
+    currentTime = newTime;
+
+    accumulator += frameTime;
+
+    while ( accumulator >= dt )
+    {
+        previousState = currentState;
+        integrate( currentState, t, dt );
+        t += dt;
+        accumulator -= dt;
+    }
+
+    const double alpha = accumulator / dt;
+
+    State state = currentState * alpha + 
+        previousState * ( 1.0 - alpha );
+
+    render( state );
+}
+```
+
+or from this [medium article](https://medium.com/@tglaiel/how-to-make-your-game-run-at-60fps-24c61210fe75)
+
+```c
+while(running){
+    computeDeltaTimeSomehow();
+    accumulator += deltaTime;
+    while(accumulator >= 1.0/60.0){
+        previous_state = current_state;
+        current_state = update();
+        accumulator -= 1.0/60.0;
+    }
+    render_interpolated_somehow(previous_state, current_state, accumulator/(1.0/60.0));
+    display();
+}
+```