Release v4.6.0 - #41
Merged
Merged
Conversation
…tants ShotPhysicsContext derived c0 by reaching into DefaultAerodynamicModel for DRAG_FORCE_CONST, REF_BALL_MASS_OZ, and REF_BALL_CIRC_IN — a model-agnostic layer depending on one concrete model. Those constants describe the reference ball the empirical drag fit was taken against; they are a derivation input, not a model tunable, so they belong in physics_constants. ShotPhysicsContext no longer includes DefaultAerodynamicModel. The model retains the names as aliases to the shared constants for inspection by derived models.
Introduce a BallProperties struct (mass, circumference, derived radius) whose defaults reproduce a standard golf ball. Thread it through the FlightSimulator constructors into ShotPhysicsContext — where mass and circumference now drive c0, the surface spin speed, and the Reynolds reference — and into the three phases, which hand its radius to the aero, bounce, and roll model states in place of the hardcoded standard-ball constant. All new parameters default to a standard ball, so existing call sites are unchanged. Documents the seam in how.md and moves ball properties out of the 'what isn't pluggable' list.
The low-Re branch returned bare CD_LOW while the adjacent linear branch evaluated to CD_LOW + CD_SPIN*S at the boundary, so the spin-drag term appeared as a step at Re=0.5e5. Carry CD_SPIN*S through the low-Re branch: Cd is now continuous across the threshold and the spin contribution to drag is present at low Re as it is everywhere else.
MIN_VELOCITY_THRESHOLD served as a speed floor, a spin-magnitude floor, and a vector-length floor at once — three dimensionally distinct concepts sharing one constant. Split into MIN_SPEED (ft/s), MIN_SPIN (rad/s), and MIN_LENGTH (ft) and route each call site to the matching floor. Values are identical today, so behaviour is unchanged; the floors can now be retuned independently.
AtmosphericData had no field defaults, so the common standard-day case still forced callers to fill all seven fields. Give each field a default (59°F, sea level, no wind, dry air, 29.92 inHg) so AtmosphericData{} is a usable baseline and designated initializers need only override what differs — matching GroundSurface's existing ergonomics.
BallState::fromLaunchParameters accepted a gravity value but AerialPhase::calculateAccel overwrote acceleration each step with the hardcoded earth constant, and FlightSimulator always passed earth — so the knob did nothing past step 1 and was unreachable through the main API. Add a gravity parameter (default earth) to the FlightSimulator constructors, thread it into AerialPhase and BouncePhase for the per-step aerial acceleration, and route the same value into fromLaunchParameters. The default keeps every existing call unchanged. Documents the seam and the roll-model caveat in how.md.
The library used directory-scoped include_directories() and installed only the archive, so downstream projects could not resolve headers and find_package(golf) was unsupported. Switch to target_include_directories(golf PUBLIC ...) with BUILD/INSTALL interface paths, add a golf::golf alias, and install an exported golfTargets plus a generated golfConfig/golfConfigVersion. Consumers can now find_package(golf) and link golf::golf, or add_subdirectory and link the same target. README documents the find_package path.
…in BouncePhase BouncePhase embedded an AerialPhase that was never initialize()d and carried cached scalars meaningless in the bounce context; it worked only because calculateAccelerations recomputed everything and only state.acceleration escaped. Extract the wind snapshot and the aero-plus-gravity computation into stateless helpers shared by both phases, give BouncePhase its own model/atmosphere/gravity members, and drop the nested phase. Removes the duplicate calculateAccel/calculateAccelerations naming. Behaviour is unchanged.
The aerial and between-bounce integration was hardwired into the phases, leaving the integration scheme the one flight stage a user could not replace. Add an Integrator interface that advances position and velocity given an acceleration field it can sample at trial states, plus a DefaultIntegrator implementing the existing semi-implicit Euler scheme. AerialPhase and BouncePhase now delegate stepping to it, and FlightSimulator exposes it as a trailing constructor parameter. AerodynamicModel and AerodynamicState are unchanged, so this is additive. The default reproduces existing trajectories exactly. Documents the seam in how.md and corrects the AerodynamicModel note that said the integrator could not be swapped.
The acceleration field handed to the Integrator was rebuilt as a fresh std::function every step. Its captures exceed the std::function small-buffer size, so each flight step heap-allocated. Build it once per phase and read the per-step spin through a shared cell the phase mutates in place.
- Set INSTALL_GTEST OFF so a test-configured build's `cmake --install` ships only libgolf + its package config, not gtest/gmock. - Document why Release builds must not add -ffast-math: it folds NaN comparisons and breaks the convergence guards.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Pluggable
Integratorinterface for the flight phases.BallProperties— no longer pinned toSTD_BALL_*.Packaging
golf::golfalias,PUBLICincludes.find_packageworks; README snippet added.Correctness / quality
Cdat the low-Re threshold.physics_constants(drops the context → default-model dependency).AerialPhasede-nested fromBouncePhase.MIN_VELOCITY_THRESHOLDsplit intoMIN_SPEED/MIN_SPIN/MIN_LENGTH.AtmosphericDatadefaults to a sea-level standard day.Build
CMAKE_CXX_FLAGS_RELEASEoverride.