grillkol/FluidSim
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update

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grillkol
2026-05-05 14:02:07 +02:00
parent f16a1aa763
commit 547e8706f1
6 changed files with 425 additions and 355 deletions
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73
Program.cs
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@@ -12,24 +12,27 @@ public class Program
private const double DrawFrequency = 60.0;
private static Scenario scenario;
// Speed control
private static double desiredSpeed = 0.0001;
//private static double desiredSpeed = 1;
// Speed control (existing + new throttle)
private static double desiredSpeed = 0.01;
private static double currentSpeed = desiredSpeed;
private const double MinSpeed = 0.0001;
private const double MaxSpeed = 1.0;
private const double ScrollFactor = 1.1;
// Space‑toggle state
private static double lastDesiredSpeed = 0.1; // remembers the last non‑1.0 speed
private static bool isRealTime = false; // starts in slow‑mo (desiredSpeed != 1.0)
private static double lastDesiredSpeed = 0.1;
private static bool isRealTime = false;
// Throttle smoothing
private static double targetThrottle = 0.0; // 1.0 when W is pressed, 0.0 otherwise
private static double currentThrottle = 0.0;
private const double ThrottleSmoothing = 8.0; // rate of change
private static volatile bool running = true;
public static void Main()
{
var mode = new VideoMode(new Vector2u(1280, 720));
var window = new RenderWindow(mode, "FluidSim - Helmholtz Resonator");
var window = new RenderWindow(mode, "FluidSim - Engine (W = throttle)");
window.SetVerticalSyncEnabled(true);
window.Closed += (_, _) => { running = false; window.Close(); };
window.MouseWheelScrolled += OnMouseWheel;
@@ -39,12 +42,7 @@ public class Program
soundEngine.Volume = 70;
soundEngine.Start();
// Choose one scenario. The Helmholtz resonator is fully updated.
//scenario = new HelmholtzResonatorScenario();
//scenario = new PipeResonatorScenario(); // needs update to new API
//scenario = new SodShockTubeScenario(); // needs update to new API
scenario = new EngineScenario(); // also works (provided earlier)
scenario = new EngineScenario();
scenario.Initialize(SampleRate);
var stopwatch = Stopwatch.StartNew();
@@ -52,18 +50,13 @@ public class Program
double drawInterval = 1.0 / DrawFrequency;
double lastSpeedUpdateTime = stopwatch.Elapsed.TotalSeconds;
// Resampling buffer
var simBuffer = new List<float>(4096);
double readIndex = 0.0;
// Prime the buffer with a few samples
for (int i = 0; i < 4; i++)
simBuffer.Add(scenario.Process());
long totalSimSteps = simBuffer.Count;
long totalOutputSamples = 0;
double lastRealTime = stopwatch.Elapsed.TotalSeconds;
const int outputChunk = 256;
float[] outputBuf = new float[outputChunk];
@@ -72,16 +65,22 @@ public class Program
window.DispatchEvents();
double currentRealTime = stopwatch.Elapsed.TotalSeconds;
double dtSpeed = currentRealTime - lastSpeedUpdateTime;
double dtClock = currentRealTime - lastSpeedUpdateTime;
lastSpeedUpdateTime = currentRealTime;
// Smoothly transition currentSpeed → desiredSpeed
double smoothingRate = 8.0; // higher = faster catch‑up
currentSpeed += (desiredSpeed - currentSpeed) * (1.0 - Math.Exp(-smoothingRate * dtSpeed));
// Smooth simulation speed
double speedSmoothing = 8.0;
currentSpeed += (desiredSpeed - currentSpeed) * (1.0 - Math.Exp(-speedSmoothing * dtClock));
// ---------- Generate audio ----------
// ---- THROTTLE INPUT ----
targetThrottle = Keyboard.IsKeyPressed(Keyboard.Key.W) ? 1.0 : 0.0;
currentThrottle += (targetThrottle - currentThrottle) * (1.0 - Math.Exp(-ThrottleSmoothing * dtClock));
// Push to engine scenario (if it's an EngineScenario)
if (scenario is EngineScenario engine)
engine.Throttle = currentThrottle;
// Generate audio
double targetAudioClock = currentRealTime + 0.05;
while (totalOutputSamples < targetAudioClock * SampleRate && running)
{
int toGenerate = (int)Math.Min(
@@ -103,11 +102,9 @@ public class Program
int i0 = (int)readIndex;
int i1 = i0 + 1;
double frac = readIndex - i0;
float y0 = simBuffer[Math.Clamp(i0, 0, simBuffer.Count - 1)];
float y1 = simBuffer[Math.Clamp(i1, 0, simBuffer.Count - 1)];
outputBuf[i] = (float)(y0 + (y1 - y0) * frac);
readIndex += currentSpeed;
while (readIndex >= 1.0 && simBuffer.Count > 2)
@@ -119,23 +116,23 @@ public class Program
int accepted = soundEngine.WriteSamples(outputBuf, toGenerate);
totalOutputSamples += accepted;
if (accepted < toGenerate)
break;
}
// ---------- Drawing & window title ----------
// Drawing & title
if (currentRealTime - lastDrawTime >= drawInterval)
{
double actualSpeed = totalOutputSamples / (currentRealTime * SampleRate);
double simTime = totalSimSteps / (double)SampleRate;
string toggleHint = isRealTime ? "[Space] slow mo" : "[Space] real time";
string throttleHint = Keyboard.IsKeyPressed(Keyboard.Key.W) ? "W held" : "W released";
window.SetTitle(
$"{toggleHint} Sim: {simTime:F2}s | " +
$"Speed: {currentSpeed:F4}x → {desiredSpeed:F4}x | " +
$"Actual: {actualSpeed:F2}x"
$"{toggleHint} {throttleHint} " +
$"Thr: {currentThrottle:F2} " +
$"Speed: {currentSpeed:F3}x → {desiredSpeed:F3}x " +
$"Act: {actualSpeed:F2}x"
);
window.Clear(Color.Black);
scenario.Draw(window);
window.Display();
@@ -147,22 +144,18 @@ public class Program
window.Dispose();
}
// (Mouse wheel, space toggle unchanged)
private static void OnMouseWheel(object? sender, MouseWheelScrollEventArgs e)
{
bool wasRealTime = Math.Abs(desiredSpeed - 1.0) < 1e-6;
if (e.Delta > 0)
desiredSpeed *= ScrollFactor;
else if (e.Delta < 0)
desiredSpeed /= ScrollFactor;
desiredSpeed = Math.Clamp(desiredSpeed, MinSpeed, MaxSpeed);
// Update the remembered slow‑mo speed (unless we are exactly at 1.0)
if (!wasRealTime || Math.Abs(desiredSpeed - 1.0) > 1e-6)
lastDesiredSpeed = desiredSpeed;
// Update isRealTime flag
isRealTime = Math.Abs(desiredSpeed - 1.0) < 1e-6;
}
@@ -171,15 +164,9 @@ public class Program
if (e.Code == Keyboard.Key.Space)
{
if (isRealTime)
{
// Switch to the remembered slow speed
desiredSpeed = lastDesiredSpeed;
}
else
{
// Switch back to real time
desiredSpeed = 1.0;
}
isRealTime = !isRealTime;
}
}