Real-Time 2D GPU Fluid Simulation

A real-time 2D fluid simulation built in Unity using compute shaders.

This project explores GPU-based fluid simulation techniques, interactive obstacle drawing, and real-time visualization tools. The simulation runs entirely on the GPU and allows users to experiment with different emitters, obstacle layouts, and debugging views while observing fluid behavior in real time.

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Features

• Real-time GPU fluid simulation
• Interactive obstacle drawing
• Point, line, vortex, and directional emitters
• Gravity support
• Vorticity confinement for swirling fluid motion
• Multiple debug visualization modes
• Runtime performance statistics
• Interactive showcase UI

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Controls

Input	Action
Left Mouse	Add fluid density and velocity
Right Mouse	Draw obstacles
Middle Mouse	Clear obstacles
Q / W / E / R / A / S / D / F / G / Z / X / C / V	Trigger showcase emitters
1 - 7	Switch debug visualization modes

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Debug Views

The project includes several visualization modes for inspecting the simulation:

• Density
• Velocity Magnitude
• Velocity Direction
• Divergence
• Pressure
• Obstacle Mask

These views help visualize how different stages of the fluid solver behave internally.

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Technical Details

The simulation is implemented using Unity Compute Shaders and is based on a grid-based fluid solver.

Core simulation steps include:

• Velocity advection
• Density advection
• Gravity
• Curl computation
• Vorticity confinement
• Divergence calculation
• Iterative pressure solving
• Velocity projection

On my test machine, the simulation measures approximately 0.28 ms GPU time.

Test Machine

• NVIDIA GeForce RTX 4070
• Intel i5-13400
• 32 GB RAM

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Why I Built This

The goal of this project was to deepen my understanding of GPU programming, compute shaders, and real-time simulation techniques.

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Future Improvements

Potential future work includes:

• Fluid rendering improvements
• Colored fluids and fluid mixing
• Additional emitter types
• Performance optimizations
• 3D fluid simulation experiments

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Credits & References

This project was inspired by:

• Mike Ash — Fluid Simulation for Dummies
• Sebastian Lague — Coding Adventure: Simulating Smoke