Dynamic mover by erincatto · Pull Request #1072 · erincatto/box2d

erincatto · 2026-06-21T05:22:03Z

Experimental dynamic mover.
Added mover and pogo joints for the dynamic mover.
Refactored geometric mover.
Redesigned pre-solve callback
Added config.h

CI fix for pogo

update draw container

Copilot

Pull request overview

Adds an experimental “dynamic mover” feature set to Box2D, including new joint types to drive a character-style dynamic body, plus determinism/recording/snapshot updates needed to support rollback/replay and cross-platform builds.

Changes:

Introduces mover joint and pogo joint (core + public API) and adds new sample implementations (dynamic + geometric movers).
Updates pre-solve callback API (manifold-edit based) and adds a pre-continuous callback for TOI filtering.
Improves determinism tooling: snapshot restore event-buffer reset, world state hashing, recording opcode/version updates, CI/build hardening.

Reviewed changes

Copilot reviewed 68 out of 73 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
test/test_world.c	Updates world API coverage test for pre-solve callback signature/args.
test/test_snapshot.c	Adds regression test for restore clearing transient event buffers; validates state hash.
test/test_recording.c	Updates joint destroy call to new signature.
test/test_distance.c	Extends distance tests; initializes new input fields; adds short-edge regression coverage.
test/main.c	Routes MSVC CRT error/assert reporting to stderr for headless runs.
src/world_snapshot.c	Clears transient event buffers on restore; hashes new joint types; adds state-hash API impl.
src/wheel_joint.c	Adjusts limit setter behavior; updates debug draw transform composition.
src/weld_joint.c	Updates debug draw transform composition.
src/timer.c	Fixes Windows header include casing for MinGW-on-Linux.
src/solver.c	Hooks pre-continuous callback; adds determinism note; adjusts validation call site.
src/shape.c	Removes wakeBodies plumbing from shape/contact teardown/reset proxy paths.
src/revolute_joint.c	Clamps limits to valid range; updates debug draw transform composition.
src/recording.h	Bumps recording minor version; adds mover/pogo joint defs to recording types.
src/recording.c	Adds mover/pogo joint writers; wraps record ops with a mutex for thread-safe writes.
src/recording_replay.h	Adds mover/pogo joint def readers.
src/recording_replay.c	Adds mover/pogo joint replay support; updates DestroyJoint replay; guards dispatch on rdr->ok.
src/recording_ops.inl	Reassigns opcodes; adds mover/pogo ops; removes wakeAttached arg from DestroyJoint op.
src/prismatic_joint.c	Adjusts limit setter behavior; updates debug draw transform composition.
src/pogo_joint.c	New pogo joint implementation (API + solver integration helpers).
src/physics_world.h	Adds preContinuousFcn slot; formatting cleanup.
src/physics_world.c	Adds denormal-flush warning; updates casts for origin-relative queries; expands pre-solve API; validation placement.
src/mover.c	Renames plane solver result field to delta.
src/mover_joint.c	New mover joint implementation (API + solver integration helpers).
src/motor_joint.c	Removes dead debug dump block and an unused include.
src/joint.h	Adds mover/pogo joint sim structs and solver hooks; simplifies destroy-joint internal signature.
src/distance.c	Adjusts overlap/cache handling and numerical epsilon criteria in GJK distance.
src/distance_joint.c	Changes length-range setter to no longer reset impulses (behavioral change).
src/contact.h	Updates destroy-contact signature to remove wakeBodies parameter.
src/contact.c	Makes pre-solve manifold-edit based; always wakes touching bodies on contact destruction.
src/CMakeLists.txt	Adds new source files; adds public config header; enables asserts in RelWithDebInfo; clarifies validation message.
src/body.h	Removes outdated todo about fixed rotation inertia.
src/body.c	Removes wakeBodies parameter from contact/joint destruction paths; fixed-rotation inertia handling; mass-data extents update.
src/atomic.h	Refines MSVC atomic loads; adds denormal-flush detection helper.
shared/utils.c	Fixes Windows header include casing for MinGW-on-Linux.
shared/human.c	Updates joint destroy calls to new signature.
shared/determinism.c	Minor assertion simplification.
samples/sample.cpp	Updates joint destroy call; updates pause key display strings.
samples/sample_joints.cpp	Updates joint destroy calls to new signature.
samples/sample_issues.cpp	Adds a note about impulse application point for stability.
samples/sample_events.cpp	Removes old platformer pre-solve sample; updates joint destroy call; minor cleanup.
samples/sample_determinism.cpp	Adjusts which steps issue queries; formatting cleanup.
samples/sample_collision.cpp	Minor cleanup to reuse radius variable.
samples/sample_benchmark.cpp	Tweaks benchmark content (joint destroy call; sensor benchmark density/layout).
samples/main.cpp	Changes pause hotkey from Space to P; fixes preprocessor nesting for alloc hook.
samples/geometric_mover.h	New geometric mover helper declarations and tuning struct.
samples/geometric_mover.cpp	New geometric mover implementation using collide/cast mover APIs and plane solver.
samples/dynamic_mover.h	New dynamic mover helper declarations and tuning struct.
samples/dynamic_mover.cpp	New dynamic mover implementation using mover+pogo joints.
samples/draw.c	Migrates sample renderer arrays to new container macros.
samples/doohickey.cpp	Updates joint destroy calls to new signature.
samples/data/map04.svg	Adds new map asset.
samples/data/map03.svg	Updates SVG metadata/path (Inkscape version + edits).
samples/data/map_right.svg	Adds new map asset.
samples/data/map_left.svg	Updates SVG metadata/path (Inkscape version + edits).
samples/container.h	Reworks dynamic array/container macros used by samples.
samples/CMakeLists.txt	Adds new mover source files to samples build.
samples/car.cpp	Removes unused locals; updates joint destroy calls.
README.md	Documents where LLMs are used in the project.
include/box2d/types.h	Adds mover/pogo public types; revises callbacks; enhances event/result documentation.
include/box2d/math_functions.h	Adjusts normalization thresholds; rewrites angle unwind to avoid remainderf dependency.
include/box2d/config.h	Adds public compile-time configuration header.
include/box2d/collision.h	Renames plane solver result field translation→delta; doc tweaks.
include/box2d/box2d.h	Exposes new APIs/types (state hash, mover/pogo, callback signature changes, destroy-joint signature change).
include/box2d/base.h	Adds config include plumbing; allows custom export macro override; adjusts Windows detection.
docs/simulation.md	Minor wording fix about mass properties.
docs/layout.xml	Updates Doxygen layout version and visibility attributes.
docs/foundation.md	Adds a blank line in multithreading section for formatting.
CMakeLists.txt	Sanitizer flag refinements; deterministic FP contraction flag logic; option ordering; Emscripten pthread flags positioning.
benchmark/main.c	Improves CLI parsing (long options, list, benchmark by name) and help text.
.gitignore	Removes some ignored files/dirs entries.
.github/workflows/build.yml	Adds workflow_dispatch; adds RelWithDebInfo runs; adds Emscripten build-only job; tweaks draft gating and sanitizer env.

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 /// Prototype for a pre-solve callback.
-/// This is called after a contact is updated. This allows you to inspect a
-/// contact before it goes to the solver. If you are careful, you can modify the
-/// contact manifold (e.g. modify the normal).
+/// This is called after a contact manifold is updated. This allows you to inspect a
+/// manifold before it goes to the solver. If you are careful, you can modify the
+/// manifold (e.g. modify the normal). You can set the manifold point count to zero disable
+/// collision.


 }

-static bool PreSolveStatic( b2ShapeId shapeIdA, b2ShapeId shapeIdB, b2Pos point, b2Vec2 normal, void* context )
+static bool PreSolveStatic( b2ShapeId shapeIdA, b2ShapeId shapeIdB, b2Manifold* manifold, void* context )


 void b2RevoluteJoint_SetLimits( b2JointId jointId, float lower, float upper )
 {
+	B2_ASSERT( lower <= upper );
+
 	b2World* world = b2GetWorld( jointId.world0 );
 	B2_REC( world, RevoluteJointSetLimits, jointId, lower, upper );
-	B2_ASSERT( lower <= upper );
-	B2_ASSERT( lower >= -0.99f * B2_PI );
-	B2_ASSERT( upper <= 0.99f * B2_PI );

 	b2JointSim* joint = b2GetJointSimCheckType( jointId, b2_revoluteJoint );
-	if ( lower != joint->revoluteJoint.lowerAngle || upper != joint->revoluteJoint.upperAngle )
-	{
-		joint->revoluteJoint.lowerAngle = b2MinFloat( lower, upper );
-		joint->revoluteJoint.upperAngle = b2MaxFloat( lower, upper );
-		joint->revoluteJoint.lowerImpulse = 0.0f;
-		joint->revoluteJoint.upperImpulse = 0.0f;
-	}
+	float lowerAngle = b2MinFloat( lower, upper );
+	float upperAngle = b2MaxFloat( lower, upper );
+	joint->revoluteJoint.lowerAngle = b2ClampFloat( lowerAngle, -0.99f * B2_PI, 0.99f * B2_PI );
+	joint->revoluteJoint.upperAngle = b2ClampFloat( upperAngle, -0.99f * B2_PI, 0.99f * B2_PI );
 }


 void b2PrismaticJoint_SetLimits( b2JointId jointId, float lower, float upper )
 {
 	b2World* world = b2GetWorld( jointId.world0 );
 	B2_REC( world, PrismaticJointSetLimits, jointId, lower, upper );
 	B2_ASSERT( lower <= upper );

 	b2JointSim* joint = b2GetJointSimCheckType( jointId, b2_prismaticJoint );
-	if ( lower != joint->prismaticJoint.lowerTranslation || upper != joint->prismaticJoint.upperTranslation )
-	{
-		joint->prismaticJoint.lowerTranslation = b2MinFloat( lower, upper );
-		joint->prismaticJoint.upperTranslation = b2MaxFloat( lower, upper );
-		joint->prismaticJoint.lowerImpulse = 0.0f;
-		joint->prismaticJoint.upperImpulse = 0.0f;
-	}
+	joint->prismaticJoint.lowerTranslation = b2MinFloat( lower, upper );
+	joint->prismaticJoint.upperTranslation = b2MaxFloat( lower, upper );
 }


 void b2WheelJoint_SetLimits( b2JointId jointId, float lower, float upper )
 {
 	b2World* world = b2GetWorld( jointId.world0 );
 	B2_REC( world, WheelJointSetLimits, jointId, lower, upper );
 	B2_ASSERT( lower <= upper );

 	b2JointSim* joint = b2GetJointSimCheckType( jointId, b2_wheelJoint );
-	if ( lower != joint->wheelJoint.lowerTranslation || upper != joint->wheelJoint.upperTranslation )
-	{
-		joint->wheelJoint.lowerTranslation = b2MinFloat( lower, upper );
-		joint->wheelJoint.upperTranslation = b2MaxFloat( lower, upper );
-		joint->wheelJoint.lowerImpulse = 0.0f;
-		joint->wheelJoint.upperImpulse = 0.0f;
-	}
+	joint->wheelJoint.lowerTranslation = b2MinFloat( lower, upper );
+	joint->wheelJoint.upperTranslation = b2MaxFloat( lower, upper );
 }


 void b2DistanceJoint_SetLengthRange( b2JointId jointId, float minLength, float maxLength )
 {
 	b2World* world = b2GetWorld( jointId.world0 );
 	B2_REC( world, DistanceJointSetLengthRange, jointId, minLength, maxLength );
 	b2JointSim* base = b2GetJointSimCheckType( jointId, b2_distanceJoint );
 	b2DistanceJoint* joint = &base->distanceJoint;

 	minLength = b2ClampFloat( minLength, B2_LINEAR_SLOP, B2_HUGE );
 	maxLength = b2ClampFloat( maxLength, B2_LINEAR_SLOP, B2_HUGE );
 	joint->minLength = b2MinFloat( minLength, maxLength );
 	joint->maxLength = b2MaxFloat( minLength, maxLength );
-	joint->impulse = 0.0f;
-	joint->lowerImpulse = 0.0f;
-	joint->upperImpulse = 0.0f;
 }


+	{
+		m_planeCount = 0;
+
+		b2World_CollideMover( m_worldId, m_position, &m_capsule, m_filter, PlaneResultFcn, this );


erincatto added 30 commits June 1, 2026 23:21

doxygen update

13746ad

wip

56b6c9b

Merge remote-tracking branch 'origin/main' into dmover

fcc546f

wip

0f420fd

wip

914e48f

Merge remote-tracking branch 'origin' into dmover

36de47d

wip

30c1ed2

fix bug in snapshot restore

c7a044a

fixes

68e36ec

wip

d7f263c

recording mutex

249f8d4

wip

0b0155b

wip

49fce4f

improve sanitizer usage

fbbfe79

wip

8f825b8

CI fix

1fb8ee0

determinism tests in optimized builds

eb68158

CI fix for pogo

CI fix

f093f90

update draw container

pogo joint

af2c8f2

wip

605fdf1

Remove lots of bools that disable waking bodies for simplification.

e866438

wip

3d910d2

wip

b3ff7fd

separate mover classes

9c7693f

unify mover samples

fcfb52a

improve tolerances

4288a51

mover clean up

01c39f2

improved pre-solve callbacks

31107d0

CI fix

32e082c

CI fix

7eda852

erincatto added 2 commits August 16, 2026 16:50

hook up new joints to recording

a33ba7a

fixes

dbc836c

erincatto requested a lite review from Copilot August 17, 2026 06:12

Copilot started reviewing on behalf of erincatto August 17, 2026 06:13 View session

Copilot AI reviewed Aug 17, 2026

View reviewed changes

erincatto added 9 commits August 16, 2026 23:18

CI fix

16d0af7

dynamic mover tweaks

f403d6b

fix comment

200c0be

revise mover state machine

4d557c1

improve jumping

92b6fa2

reorder mover logic

103cbdb

jump consistency

9407f1b

CI fix

86014a0

surface velocity

7022983

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Dynamic mover - #1072

Dynamic mover#1072
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erincatto commented Jun 21, 2026 •

edited

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erincatto commented Jun 21, 2026 •

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