Constants. More...
Macros | |
| #define | B2_HUGE ( ( 100.0f * 1000.0f ) * b2_lengthUnitsPerMeter ) |
| Used to detect bad values. | |
| #define | B2_MAX_WORKERS 32 |
| Maximum parallel workers. Used for some fixed size arrays. | |
| #define | B2_MAX_TASKS 256 |
| Maximum number of tasks queued per world step. | |
| #define | B2_GRAPH_COLOR_COUNT 24 |
| Maximum number of colors in the constraint graph. | |
| #define | B2_LINEAR_SLOP ( 0.005f * b2_lengthUnitsPerMeter ) |
| A small length used as a collision and constraint tolerance. | |
| #define | B2_MAX_WORLDS 128 |
| Maximum number of simultaneous worlds that can be allocated. | |
| #define | B2_NAME_LENGTH 10 |
| Maximum length of the body name. Can be 0 if you don't need names. | |
| #define | B2_MAX_ROTATION ( 0.25f * B2_PI ) |
| The maximum rotation of a body per time step. | |
| #define | B2_SPECULATIVE_DISTANCE ( 4.0f * B2_LINEAR_SLOP ) |
| Box2D uses limited speculative collision. | |
| #define | B2_CONTACT_RECYCLE_DISTANCE ( 10.0f * B2_LINEAR_SLOP ) |
| The default contact recycling distance. | |
| #define | B2_CONTACT_RECYCLE_COS_ANGLE ( 0.98f ) |
| The default contact recycling world angle threshold. 0.98 ~= 11.5 degrees. | |
| #define | B2_MAX_AABB_MARGIN ( 0.05f * b2_lengthUnitsPerMeter ) |
| This is used to fatten AABBs in the dynamic tree. | |
| #define | B2_AABB_MARGIN_FRACTION 0.125f |
| For small objects the margin is limited to this fraction times the maximum extent. | |
| #define | B2_TIME_TO_SLEEP 0.5f |
| The time that a body must be still before it will go to sleep. In seconds. | |
| #define | B2_MAX_RESTITUTION_ITERATIONS 63 |
| The maximum number of restitution iterations. Needed to avoid a solver overflow. | |
Constants.
Some can be configured. I try to include most internal constants here for convenience and clarity. This is why they are not all configurable.
| #define B2_GRAPH_COLOR_COUNT 24 |
Maximum number of colors in the constraint graph.
Constraints that cannot find a color are added to the overflow set, which is solved single-threaded. The compound barrel benchmark has minor overflow with 24 colors
| #define B2_HUGE ( ( 100.0f * 1000.0f ) * b2_lengthUnitsPerMeter ) |
Used to detect bad values.
Positions greater than about 16km will have precision problems in single precision, so 100km as a limit should be fine in all cases. In large world mode the broad-phase starts to have excessive padding at 10,000km, so a value beyond 100,000km is extreme.
| #define B2_LINEAR_SLOP ( 0.005f * b2_lengthUnitsPerMeter ) |
A small length used as a collision and constraint tolerance.
Usually it is chosen to be numerically significant, but visually insignificant. In meters. Normally this is 0.5cm.
| #define B2_MAX_AABB_MARGIN ( 0.05f * b2_lengthUnitsPerMeter ) |
This is used to fatten AABBs in the dynamic tree.
This allows proxies to move by a small amount without triggering a tree adjustment. This is in meters. Normally this is 5cm. This has been tuned on benchmarks and I found that keeping the margin small improves performance by reducing the number of contacts. I used to keep this larger in the past to avoid tree insert and remove churn. But the broad-phase no longer works that way and now uses a two-phase refit and rebuild setup similar to Jolt.
| #define B2_MAX_ROTATION ( 0.25f * B2_PI ) |
The maximum rotation of a body per time step.
This limit is very large and is used to prevent numerical problems. You shouldn't need to adjust this.
| #define B2_MAX_TASKS 256 |
Maximum number of tasks queued per world step.
b2EnqueueTaskCallbackFcn will never be called more than this per world step. This is related to B2_MAX_WORKERS. With 32 workers, the maximum observed task count is 130. This allows an external task system to use a fixed size array for Box2D tasks, which may help with creating stable user task pointers.
| #define B2_SPECULATIVE_DISTANCE ( 4.0f * B2_LINEAR_SLOP ) |
Box2D uses limited speculative collision.
This reduces jitter. Normally this is 2cm.
1.18.0 