lua.box2d.world.cast

hits = world:cast(ray)

if ray.points is set then this is a polygon shape cast, otherwise this is an ray cast.

cast a ray and return an array of hits

ray.points

Tightly packed array of points for the shape. Maximum number of points is B2_MAX_POLYGON_VERTICES (8) To cast a circle shape, just use a radius and a single point at the origin.

ray.radius

Radius of the shape to cast, does not work unless you also set points.

ray.origin

Starting world point of ray

ray.translation

The ray to cast

ray.filter_categoryBits
ray.filter_maskBits
ray.filter

Filter masks, ray.filter is a previously set name that we will convert using world:bits(name) into filter_categoryBits and filter_maskBits unless they are already set.

hit=hits[1]
hit=hits[2]
etc

Returned hits which are sorted by fraction from low to high.

Initial overlaps are returned with a fraction of 0 and normal of 0. If you want the first actual hit you should ignore these and get the first hit with a non zero normal.

If hits[1] is nil then there where no hits.

hit.shapeID

BoxID of the shape we hit.

hit.shape

Table of the shape we hit. Filled in from shapeID for your convenience, if somehow (?) shapeID is invalid then this will be nil. Shapes have a uid that you can use to map shapes to game objects.

hit.fraction

0-1 value, indicating how far from the origin the ray traveled.

hit.point

Table containing world coordinates of the hit point.

hit.normal

Table containing shape normal at the hit point.

hits.leafVisits
hits.nodeVisits

Contain extra debug information