SpacePeanut is a toy cosmology simulator with an Imgui UI and an OpenGL renderer, built on top of SDL3. Shared-memory CPU parallelism utilizing either C++ std::execution or OpenMP is used to allow real-time visualization of simulations containing millions of particles on common laptops.
- Arcball camera
- Input and control UI
- Built-in renderer that uses grid mass density to color particles
- Dynamic color palette
The particle-mesh computational technique allows efficient simulation of gravitational forces in a system of many interacting particles. The primary feature of this method is extremely fast calculation of long-range forces. However, the method neglects to represent short range forces (on the scale of the grid resolution). The method can be broken down into 4 coherent steps:
- Transfer particle mass to the grid. The cloud-in-cell method is used here for particle<->grid transfer.
- Calculate grid gravitational potential by solving Poisson's equation. Periodic boundary conditions mean we can use the Discrete Fourier Transform to solve.
- Calculate grid force by taking the gradient of potential.
- Interpolate grid force onto the particles using the cloud-in-cell method.
This project uses CMake with the Ninja build generator. Additional prerequisites include:
- OpenMP or the Intel TBB library, depending on backend used
- OpenGL
- GLEW
- FFTW3
CMake presets are set, so the build is best invoked with one of the following combinations of Release or Debug builds and OpenMP or std::execution backends:
cmake --workflow --preset rel-omp
cmake --workflow --preset rel-std
cmake --workflow --preset dbg-omp
cmake --workflow --preset dbg-std
