fix joint crash. also fix test_move and shape_collide

Update box2d_joint.cpp Update README.md update readme Update README.md
appsinacup · Aug 2, 2023 · 40e58f9 · 40e58f9
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,8 +2,9 @@
 
 ## [v0.5](https://github.com/godot-box2d/godot-box2d/releases/tag/v0.5)
 
-- Fix shapes not updating(changing shape geometry)
-- Fix deleting shapes/body/spaces bug
+- Fix [shapes not updating(changing shape geometry)](https://github.com/godot-box2d/godot-box2d/issues/16)
+- Fix [deleting shapes/body/spaces bug](https://github.com/godot-box2d/godot-box2d/issues/18)
+- Possible fix for [collision between static body and area bug](https://github.com/godot-box2d/godot-box2d/issues/19)
 
 ## [v0.4](https://github.com/godot-box2d/godot-box2d/releases/tag/v0.4)
 

diff --git a/README.md b/README.md
@@ -6,6 +6,14 @@
 
 A [box2D](https://github.com/erincatto/box2d) physics server for [Godot Engine](https://github.com/godotengine/godot) 4.1, implemented as a GDExtension.
 
+Currently passes 127/150 of [Godot-Physics-Tests](https://github.com/fabriceci/Godot-Physics-Tests).
+
+## Determinism
+
+Box2D is binary deterministic, but doesn't make any guaratee as for cross platform determinism.
+Godot Box2D should also be binary deterministic, however no such tests were run yet.
+However, when Box2C gets released, that will be one of this repo's goals to make it cross platform deterministic (from what I spoke to Erin, it should be just the cos and sin functions that are not determinstic).
+
 ## Limitations
 
 - Having non symetrical physics mask/layers results in no collision. Eg. if we had the following:

diff --git a/src/joints/box2d_joint.cpp b/src/joints/box2d_joint.cpp
@@ -73,8 +73,7 @@ void Box2DJoint::make_pin(const Vector2 &p_anchor, Box2DBody *p_body_a, Box2DBod
 	joint_def = revolute_joint_def;
 	common.body_a = p_body_a;
 	common.body_b = p_body_b;
-	// body_a and body_b are set when joint is created
-	configured = true;
+	configured = common.body_a && common.body_b;
 }
 
 void Box2DJoint::make_groove(const Vector2 &p_a_groove1, const Vector2 &p_a_groove2, const Vector2 &p_b_anchor, Box2DBody *p_body_a, Box2DBody *p_body_b) {
@@ -90,8 +89,7 @@ void Box2DJoint::make_groove(const Vector2 &p_a_groove1, const Vector2 &p_a_groo
 	joint_def = prismatic_joint_def;
 	common.body_a = p_body_a;
 	common.body_b = p_body_b;
-	// body_a and body_b are set when joint is created
-	configured = true;
+	configured = common.body_a && common.body_b;
 }
 
 void Box2DJoint::make_damped_spring(const Vector2 &p_anchor_a, const Vector2 &p_anchor_b, Box2DBody *p_body_a, Box2DBody *p_body_b) {
@@ -104,8 +102,7 @@ void Box2DJoint::make_damped_spring(const Vector2 &p_anchor_a, const Vector2 &p_
 	joint_def = distance_joint_def;
 	common.body_a = p_body_a;
 	common.body_b = p_body_b;
-	// body_a and body_b are set when joint is created
-	configured = true;
+	configured = common.body_a && common.body_b;
 }
 
 void Box2DJoint::set_pin_softness(real_t p_softness) {
@@ -121,7 +118,7 @@ void Box2DJoint::set_damped_spring_rest_length(real_t p_damped_spring_rest_lengt
 		return;
 	}
 	damped_spring.rest_length = godot_to_box2d(p_damped_spring_rest_length);
-	if (joint && (b2DistanceJoint *)joint) {
+	if (joint) {
 		b2DistanceJoint *distance_joint = (b2DistanceJoint *)joint;
 		distance_joint->SetLength(damped_spring.rest_length);
 	}
@@ -135,7 +132,7 @@ void Box2DJoint::set_damped_spring_stiffness(real_t p_damped_spring_stiffness) {
 		return;
 	}
 	damped_spring.stiffness = godot_to_box2d(p_damped_spring_stiffness);
-	if (joint && (b2DistanceJoint *)joint && common.body_a && common.body_b) {
+	if (joint && common.body_a && common.body_b) {
 		b2DistanceJoint *distance_joint = (b2DistanceJoint *)joint;
 		float stiffness = 0;
 		float damping = 0;
@@ -152,7 +149,7 @@ void Box2DJoint::set_damped_spring_damping(real_t p_damped_spring_damping) {
 		return;
 	}
 	damped_spring.damping = godot_to_box2d(p_damped_spring_damping);
-	if (joint && (b2DistanceJoint *)joint && common.body_a && common.body_b) {
+	if (joint && common.body_a && common.body_b) {
 		b2DistanceJoint *distance_joint = (b2DistanceJoint *)joint;
 		float stiffness = 0;
 		float damping = 0;
@@ -172,6 +169,10 @@ Box2DBody *Box2DJoint::get_body_b() {
 }
 
 b2JointDef *Box2DJoint::get_b2JointDef() {
+	if (!common.body_a || !common.body_b) {
+		WARN_PRINT("Cannot configure joint. Missing one body.");
+		return joint_def;
+	}
 	switch (type) {
 		case PhysicsServer2D::JointType::JOINT_TYPE_PIN: {
 			b2RevoluteJointDef *revolute_joint_def = (b2RevoluteJointDef *)joint_def;
@@ -184,6 +185,7 @@ b2JointDef *Box2DJoint::get_b2JointDef() {
 			distance_joint_def->Initialize(common.body_a->get_b2Body(), common.body_b->get_b2Body(), common.anchor_a, common.anchor_b);
 
 			distance_joint_def->length = damped_spring.rest_length;
+			distance_joint_def->minLength = 0;
 		} break;
 		case PhysicsServer2D::JointType::JOINT_TYPE_GROOVE: {
 			b2PrismaticJointDef *prismatic_joint_def = (b2PrismaticJointDef *)joint_def;

diff --git a/src/servers/physics_server_box2d.cpp b/src/servers/physics_server_box2d.cpp
@@ -983,7 +983,7 @@ bool PhysicsServerBox2D::_body_collide_shape(const RID &p_body, int32_t p_body_s
 	}
 	Box2DDirectSpaceState *space_state = (Box2DDirectSpaceState *)body->get_space_state();
 	ERR_FAIL_COND_V(!space_state, false);
-	return space_state->_collide_shape(shape->get_self(), p_shape_xform, p_motion, 0, body->get_collision_mask(), true, true, p_results, p_result_max, p_result_count);
+	return space_state->_collide_shape(shape->get_self(), p_shape_xform, p_motion, 0, body->get_collision_mask(), true, false, p_results, p_result_max, p_result_count);
 }
 void PhysicsServerBox2D::_body_set_pickable(const RID &p_body, bool p_pickable) {
 	Box2DBody *body = body_owner.get_or_null(p_body);
@@ -1001,8 +1001,8 @@ bool PhysicsServerBox2D::_body_test_motion(const RID &p_body, const Transform2D
 		shapes.append(shape);
 	}
 
-	Vector<b2Fixture *> query_result = Box2DSweepTest::query_aabb_motion(shapes, p_from, p_motion, p_margin, 0xff, true, true, (Box2DDirectSpaceState *)body->get_space_state());
-	Vector<SweepTestResult> sweep_test_results = Box2DSweepTest::multiple_shapes_cast(shapes, p_from, p_motion, p_margin, 0xff, true, true, 2048, query_result, (Box2DDirectSpaceState *)body->get_space_state());
+	Vector<b2Fixture *> query_result = Box2DSweepTest::query_aabb_motion(shapes, p_from, p_motion, p_margin, 0xff, true, false, (Box2DDirectSpaceState *)body->get_space_state());
+	Vector<SweepTestResult> sweep_test_results = Box2DSweepTest::multiple_shapes_cast(shapes, p_from, p_motion, p_margin, 0xff, true, false, 2048, query_result, (Box2DDirectSpaceState *)body->get_space_state());
 	SweepTestResult sweep_test_result = Box2DSweepTest::closest_result_in_cast(sweep_test_results);
 	PhysicsServer2DExtensionMotionResult &current_result = *p_result;
 	if (!sweep_test_result.collision) {