SPH

A real time, GPU-based, fluid simulation using smooth particle hydrodynamics done as a solo project for my Computer Animation (COMP 6311) class in Concordia University, Montreal. The project is written in C++ and the rendering is done using OpenGl, all SPH computations occur in the GPU through the use of compute shaders, nearest neighbour computations are also done through the use of multiple compute shaders. The simulation is able to render more than 100,000 particles in real time because of the parallel nature of the GPU.

Contents:

• Images

• Videos

• Setup Guide

• Functionality

• Report

• External Libraries

• References

Videos

Velocity Visualization

Velocity_Visualization.mp4

Standard Visualization

WaveGenerator.mp4

collision.mp4

Images

Setup Guide

Requirements:

• Windows OS (10+)

• Minimum 1536 work groups supported by the GPU

  • This program makes use of compute shaders through OpenGL. At the moment, the number of work groups in the shader is set to 1536. If your GPU supports less than 1536 work groups then you will have to go into the .comp files included in the project and change the work group size in local_size_x.

Using the program:

Simply download the SPH folder and launch the executable. (NOTE: It is important that you launch the executable in the folder provided otherwise it will be unable to locate the shader files)

Controls

• Press G to toggle the camera/mouse movement
• Use the arrow keys to move an object along the x and y axis (once you create an object)
• Use Q and E to move and object along the z axis
• Create an object by either loading one of the scenes in the simulation paramters or going into object parameters and adding a barrier

Functionality

Parameter Tuning

Through the ImGui UI the user can manipulate the parameters of the SPH simulation. These parameters include the dynamic viscocity coefficient, the number of particles and more. Warning, at the extremes the parameters become unstable and may result in unexpected behavior.

Bounding Box Tuning

The scale of the bounding box can be manipulated in real time, the outline can also be toggled on or off

Object Tuning

An object can also be added to the scene, this object can collide with the smoothed particles and multiple object configurations can be explored

Report

SPHSimulationsOnTheGPU.pdf

External Libraries Used

• GLFW
• Glad
• ImGui

References and Attributions

LearnOpenGL

The camera, shader, and compute shader class used in this project are taken from the OpenGl tutorial series LearnOpenGL by Joey de Vires. The classes have been slightly modified to provide functionality specific to my use case. https://learnopengl.com/Getting-started/Camera https://learnopengl.com/Getting-started/Shaders https://learnopengl.com/Guest-Articles/2022/Compute-Shaders/Introduction

Code is written by Joey de Vires (LearnOpengl) https://twitter.com/JoeyDeVriez.

LearnOpenGl code is available for use under the following liscence:

https://creativecommons.org/licenses/by-nc/4.0/legalcode

OpenGlTutorial

The following learn-opengl tutorial was used to guide my implementation of the billboarded spheres used for rendering. http://www.opengl-tutorial.org/intermediate-tutorials/billboards-particles/billboards/

Fluid Engine Development

The following book by doyub-kim was used to learn about smooth particle hydrodynamics and the smoothing kernels used in this project are taken directly from this source. Kim, D. (2017). Fluid Engine Development (1st ed.). A K Peters/CRC Press. https://doi.org/10.1201/b22137