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| author | Emil A. Overbeck <emil.a.overbeck@gmail.com> | 2026-07-18 00:59:18 +0200 |
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| committer | Emil A. Overbeck <emil.a.overbeck@gmail.com> | 2026-07-18 00:59:18 +0200 |
| commit | 0837872bed3d97d3433d7e0cbafffa7f271ebee1 (patch) | |
| tree | d14aaa95cd2070ca65212e24b3df98f25468cbed /research/tech-stack.org | |
| parent | 655ec946e63fcf2234f67a837cc7602099b6c301 (diff) | |
| download | forts_clone-0837872bed3d97d3433d7e0cbafffa7f271ebee1.tar.gz forts_clone-0837872bed3d97d3433d7e0cbafffa7f271ebee1.zip | |
Deterministic physics doc
Diffstat (limited to 'research/tech-stack.org')
| -rw-r--r-- | research/tech-stack.org | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/research/tech-stack.org b/research/tech-stack.org index ce0a9c1..3e43e44 100644 --- a/research/tech-stack.org +++ b/research/tech-stack.org @@ -436,6 +436,12 @@ my_mod/ * Deterministic Simulation Design +NOTE: the authoritative plan is =research/deterministic-physics.org=. The +section below predates the custom solver and assumes Box2D owns the simulation. +It does not: the game is decided by the mass-spring solver in +=src/game/build_graph.cpp=, and Box2D is idle. The determinism work targets that +solver (strict IEEE-754 float, owned transcendentals), not Box2D. + For lockstep multiplayer, the simulation must be exactly identical on all machines. @@ -474,7 +480,9 @@ Projects to study during development: * Open Questions -- [ ] Fixed-point math fallback vs trusting Box2D v3 determinism +- [X] Fixed-point math fallback vs trusting Box2D v3 determinism — resolved: + strict IEEE-754 float on the custom solver, fixed-point held in reserve. See + =research/deterministic-physics.org=. - [ ] Exact rope simulation approach within Box2D (distance joints? soft constraints? custom spring?) - [ ] Fire propagation model (graph traversal along connected flammable |