Constraints¶

Base Constraint¶

struct nvConstraint

Base two-body constraint.

Public Members

nvConstraintType type: Type of the constraint.

void *def: Constraint definition class. (This needs to be casted)

nvRigidBody *a: First body.

nvRigidBody *b: Second body.

nv_bool ignore_collision: Ignore collision of bodies connected with this constraint.

enum nvConstraintType

Constraint types.

Contact constraint is not included because it’s handled internally by the engine.

Values:

enumerator nvConstraintType_DISTANCE: Distance constraint type. See nvDistanceConstraint.

enumerator nvConstraintType_HINGE: Hinge constraint type. See nvHingeConstraint.

enumerator nvConstraintType_SPLINE: Spline constraint type. See nvSplineConstraint.

void nvConstraint_free(nvConstraint *cons)¶

Free constraint.

It’s safe to pass NULL to this function.

Parameters:: cons – Constraint

Coefficient Mixing¶

enum nvCoefficientMix¶

Coefficient mixing type is the method to mix various coefficients values like restitution and friction.

Values:

enumerator nvCoefficientMix_AVG¶: (a + b) * 0.5

enumerator nvCoefficientMix_MUL¶: a * b

enumerator nvCoefficientMix_SQRT¶: sqrt(a * b)

enumerator nvCoefficientMix_MIN¶: min(a, b)

enumerator nvCoefficientMix_MAX¶: max(a, b)

Contact Position Correction¶

enum nvContactPositionCorrection¶

Type of algorithm used to solve position error in collisions.

In baumgarte stabilization, the position error is fed back into the velocity constraint, this is an efficient solution however it adds energy to the system.

NGS (Non-Linear Gauss-Seidel) uses pseudo-velocities to resolve the drift. It is computationally bit more expensive but more stable. It is what version 2 of Box2D uses.

Note

Changing this setting should be usually avoided unless you have a specific need or familiar with the behavior.

Warning

Nova, as of 1.0.0, doesn’t have NGS solver yet.

Values:

enumerator nvContactPositionCorrection_BAUMGARTE¶: Baumgarte stabilization.

enumerator nvContactPositionCorrection_NGS¶: Non-Linear Gauss-Seidel.