Type Function Library physics.* Return value Array of tables describing each hit Revision 2017.3060 Keywords ray, raycast, casting, physics, collision See also physics.reflectRay()
This function is used to find the objects that collide with a line, and the collision points along that line.
The positions returned are in content space while the normals returned are in local space.
If the starting position is inside an object, no hit will be registered for that object.
physics.rayCast( fromX, fromY, toX, toY, behavior )
Number. The starting x position of the ray.
Number. The starting y position of the ray.
Number. The ending x position of the ray.
Number. The ending y position of the ray.
String. The collision test behavior, in increasing order of performance cost:
"any" — Return one result, but not necessarily the closest one."closest" — Return only the closest hit from the starting point, if any. This is the default behavior."unsorted" — Return all results in no particular order."sorted" — Return all results, sorted from closest to farthest.hits will be an array of elements containing these properties:
object — The DisplayObject colliding with the line.position.x — The x collision position of object, in content space.position.y — The y collision position of object, in content space.normal.x — The x component of the normal of the surface hit in local space.normal.y — The y component of the normal of the surface hit in local space.fraction — The fraction (0..1) along the ray where the hit is located. 0 is the start point of the ray cast and 1 is the end point.local hits = physics.rayCast( 0, 0, 200, 300, "closest" )
if ( hits ) then
-- There's at least one hit
print( "Hit count: " .. tostring( #hits ) )
-- Output the results
for i,v in ipairs( hits ) do
print( "Hit: ", i, v.object, " Position: ", v.position.x, v.position.y, " Surface normal: ", v.normal.x, v.normal.y )
end
print( "The first object hit is: ", hits[1].object, " at position: ", hits[1].position.x, hits[1].position.y, " where the surface normal is: ", hits[1].normal.x, hits[1].normal.y, " and where the fraction along the ray is: ", hits[1].fraction )
else
-- No hits on raycast
end