vector_extras/doc.md

Vector helpers added by this mod

Helpers which return many positions for a shape, e.g. a line

Line functions

These may be deprecated since raycasting has been added to minetest. See e.g. minetest.line_of_sight.

• vector.line([pos, dir[, range][, alt]]): returns a table of vectors
  • dir is either a direction (when range is a number) or the start position (when range is the end position).
  • If alt is true, an old path calculation is used.
• vector.twoline(x, y): can return e.g. {{0,0}, {0,1}}
  • This is a lower-level function than vector.line; it can be used for a 2D line.
• vector.threeline(x, y, z): can return e.g. {{0,0,0}, {0,1,0}}
  • Similar to vector.twoline; this one is for the 3D case.
  • The parameters should be integers.
• vector.rayIter(pos, dir): returns an iterator for a for loop
  • pos can have non-integer values
• vector.fine_line([pos, dir[, range], scale]): returns a table of vectors
  • Like vector.line but allows non-integer positions
  • It uses vector.rayIter.

Flood Fill

• vector.search_2d(go_test, x0, y0, allow_revisit, give_map): returns e.g. {{0,0}, {0,1}}
  • This function uses a Flood Fill algorithm, so it can be used to detect positions connected to each other in 2D.
  • go_test(x, y) should be a function which returns true iff the algorithm can "fill" at the position (x, y).
  • (x0, y0) defines the start position.
  • If allow_revisit is false (the default), the function invokes go_test only once at every potential position.
  • If give_map is true (default is false), the function returns the marked table, whose indices are 2D vector indices, instead of a list of 2D positions.
• vector.search_3d(can_go, startpos, apply_move, moves): returns FIXME
  • FIXME

Other Shapes

• vector.explosion_table(r): returns e.g. {{pos1}, {pos2, true}}
  • The returned list of positions and boolean represents a sphere; if the boolean is true, the position is on the outer side of the sphere.
  • It might be used for explosion calculations; but vector.explosion_perlin should make more realistic holes.
• vector.explosion_perlin(rmin, rmax[, nparams]): returns e.g. {{pos1}, {pos2, true}}
  • This function is similar to vector.explosion_table; the positions do not represent a sphere but a more complex hole which is calculated with the help of perlin noise.
  • rmin and rmax represent the minimum and maximum radius, and nparams (which has a default value) are parameters for the perlin noise.
• vector.circle(r): returns a table of vectors
  • The returned positions represent a circle of radius r along the x and z directions; the y coordinates are all zero.
• vector.ring(r): returns a table of vectors
  • This function is similar to vector.circle; the positions are all touching each other (i.e. they are connected on whole surfaces and not only infinitely thin edges), so it is called ring instead of circle
  • r can be a non-integer number.
• vector.throw_parabola(pos, vel, gravity, point_count, time)
  • FIXME: should return positions along a parabola so that moving objects collisions can be calculated
• vector.triangle(pos1, pos2, pos3): returns a table of positions, a number and a table with barycentric coordinates
  • This function calculates integer positions for a triangle defined by pos1, pos2 and pos3, so it can be used to place polygons in minetest.
  • The returned number is the number of positions.
  • The barycentric coordinates are specified in a table with three elements; the first one corresponds to pos1, etc.

Helpers for various vector calculations

• vector.sort_positions(ps[, preferred_coords])
  • Sorts a table of vectors ps along the coordinates specified in the table preferred_coords in-place.
  • If preferred_coords is omitted, it sorts along z, y and x in this order, where z has the highest priority.
• vector.maxnorm(v): returns the Tschebyshew norm of v
• vector.sumnorm(v): returns the Manhattan norm of v
• vector.pnorm(v, p): returns the p norm of v
• vector.inside(pos, minp, maxp): returns a boolean
  • Returns true iff pos is within the closed AABB defined by minp and maxp.
• vector.minmax(pos1, pos2): returns two vectors
  • This does the same as worldedit.sort_pos.
  • The components of the second returned vector are all bigger or equal to those of the first one.
• vector.move(pos1, pos2, length): returns a vector
  • Go from pos1 length metres to pos2 and then round to the nearest integer position.
  • Made for rubenwardy
• vector.from_number(i): returns {x=i, y=i, z=i}
• vector.chunkcorner(pos): returns a vector
  • Returns the mapblock position of the mapblock which contains the integer position pos
• vector.point_distance_minmax(p1, p2): returns two numbers
  • Returns the minimum and maximum of the absolute component-wise distances
• vector.collision(p1, p2) FIXME
• vector.update_minp_maxp(minp, maxp, pos)
  • Can change minp and maxp so that pos is within the AABB defined by minp and maxp
• vector.unpack(v): returns three numbers
  • Returns v.z, v.y, v.x
• vector.get_max_coord(v): returns a string
  • Returns "x", "y" or "z", depending on which component has the biggest value
• vector.get_max_coords(v): returns three strings
  • Similar to vector.get_max_coord; it returns the coordinates in the order of their component values
  • Example: vector.get_max_coords{x=1, y=5, z=3} returns "y", "z", "x"
• vector.serialize(v): returns a string
  • In comparison to minetest.serialize, this function uses a more compact string for the serialization.

Minetest-specific helper functions

• vector.straightdelay([length, vel[, acc]]): returns a number
  • Returns the time an object takes to move length if it has velocity vel and acceleration acc
• vector.sun_dir([time]): returns a vector or nil
  • Returns the vector which points to the sun
  • If time is omitted, it uses the current time.
  • This function does not yet support the moon; at night it simply returns nil.