Rainborg

Position-based Fluid Simulation.

Dependencies

This project has a few dependencies, which CMake will try to find:

OpenGL
GLFW
GLM - Included
RapidXML - Included
TCLAP - Included
libPNG - for image output
Required for compilation on GPU:
- CUDA
- Thrust

Compilation

Once the dependencies are installed, simply run CMake on the build directly, like so:

> mkdir build
> cd build
> cmake ..

You can also configure CMake flags GPU_ENABLED and USE_PNG to enable CUDA compilation and PNG output respectively. For PNG output, make sure you have an empty directly pngs in your build directory.

> ccmake ..
# configure variables...

Once you've configured everything, run the generated Makefile:

> make

This should generate the executable ./testflow.

Running our code

Type ./testflow -h for a list of commands and their descriptions. Note that a scene file (such as the ones included in /assets) is required for the simulation to run.

Structure

Main:
- Parse command line arguments
- Windows and display loop
- Initialize things??
  - Load Files
  - Create scenes + data structures
Parser:
- Scene Parser
  - XML nodes:
  - fluid block positions, rest densities, colors, velocity, mass
    - fluid constants - viscosity, etc
  - fluid boundaries
  - camera position, rotation
  - timestep, timeframe
- Mesh Parser
  - obj file, ply (or whatever)
  - translate to mesh boundary object triangles
Scene:
- Boundaries -> Mesh objects
- FluidSim
  - Fluid Particles
    - mass, rest density (shared)
    - Position
    - Velocity
    - Color
  - Bounding box
  - FluidSim.step(dt, scene)
- Forces (gravity)

Todo

Rendering
- Spheres (with lighting)
- Optional import mesh, boundary
Simulation
- Do the thing
- Go through FOSSSim, stepper
- Boundary/collision detection handling (static rigid objects)
- Serial
  - external forces (gravity)
  - predict position
  - find neighbors
  - jacobi iterator
    - constraint, lambda
    - s-correction
    - calculate delta-p
    - collision detection response
    - update positions
  - vorticity confinement
  - position update
- Parallel
  - Buckets, arbitrary acceleration data structures
  - same thing...
- Future

References

The algorithms in this project follow the following papers:

Miles Macklin, Matthias Muller, Position Based Fluids

Takahiro Harada, Seiichi Koshizuka, Yoichiro Kawaguchi, Smoothed Particle Hydrodynamics on GPUs

Techniques for CUDA-OpenGL interop functions are used from here: http://www.nvidia.com/content/gtc/documents/1055_gtc09.pdf

Additionally, an C++ OpenGL framework by Daniel Chappuis is modified for use in this project: https://github.com/DanielChappuis/opengl-framework

Finally, some XML parsing and Math utility functions are taken from FOSSSim, the codebase from Computer Animation W4167.

yariza/Rainborg