Particle engine in C++

Uses raylib library. CMakeLists.txt is a modified version from raylib-cpp's cmake template

interesting things to highlight:

• verlet integration
• substepping

planned

• optimize collisions
  • broadphase (octree)
    • construct root node with bounds set to max and min positions of all particles, but use a single halfSize for all axes since particles have same radius for all axes
    • dynamically find the max depth, based on total bounds and average (or median or mode) particle radius
    • reason about the time complexity of having a particle in multiple child trees, when it overlaps multiple. OR have it just once in the parent
    • using indices instead of pointers
  • sleeping still particles
  • sweep and prune with insertion sort (insertion sort because of temporal coherence)
    • optimized SAP method: https://ieeexplore.ieee.org/document/10121435
• moving around with camera
• stick constraints

references:

• https://www.flipcode.com/archives/Octree_Implementation.shtml, inspiration for using centered-aabb
• https://pvigier.github.io/2019/08/04/quadtree-collision-detection.html inspo for placing shared nodes only in parent