movement and vectors

anchor

Takes:   none

Returns:   list

Returns the location of the current anchor. The anchor is the ‘pivot point’ of the orbit commands and pullin / pullout.

show anchor

around

Takes:   position (list) | vector (list) | length (number) | radius (number)

Returns:   turtles (list)

Returns a list of turtles within the cylinder created by the given parameters, in the direction indicated by the vector away from the position with the given length and radius. Useful for collision detection. See also inside, encroaching.

snappy:show without turtle around position forwarddir 200 20
[myrtle]

autoorbit

Takes:   direction (word) | degrees (number) | time (60ths of a second)

Returns:   Automatically orbits the current view turtle in the specified direction the specified number of degrees every specified 60ths of a second. noautoorbit turns it off. Subsequent autoorbits cancel previous ones.

autoorbit “left 2 5

autoorbit "up 0.5 10

back bk

Takes:   turtlesteps (number)

Returns:   none

Moves the current turtle back the specified number of turtle steps.

back 20

barriers

Takes:   none

Returns:   list

Lists the existing barriers. See setbarriers

show barriers

caught

Takes:   none

Returns:   number

Returns a value if the calling turtle passes a fence or wrap threshold. caught returns 1 if the turtle hits / passes the X1 threshold provided to wrap / fence, 2 if X2, 3 if Y1, 4 if Y2, 5 if Z1, 6 if Z2. clearcaught resets it to 0.

show caught

clearfrag

Takes:   none

Returns:   none

Clears the current list of frag points. See frag

clearfrag

direction

Takes:   position (list)

Returns:   vectors (list)

Returns a list of vectors that would point the calling turtle at the supplied list of co-ordinates.

show direction myrtle:position snappy:position
[[0 1 0] [0 0 1] [1 0 0]]

snappy:setvectors direction myrtle:position

distance

Takes:   position (list) | position (list)

Returns:   distance (number)

Returns the distance from the first given set of co-ordinates to the second given set of co-ordinates.

show distance myrtle:position snappy:position
show distance [0 0 0] [100 100 100]

divergence

Takes:   [vector1 vector2] (list) | [vector3 vector4] (list)

Returns:   degrees (number)

Divergence returns the degrees of difference (divergence) between vector1 and vector3 in a clockwise direction, that direction established using vector2 and vector4, which need to be the axis you would be pivoting on to measure that difference. So if you’re measuring the degrees of difference between two forward vectors in terms of left and right, the second vector needs to be the up vector. If you were measuring the difference in terms of up and down, you would give the right vector. Divergence is extremely useful for ball games.

show divergence {item 1 myrtle:vectors item 3 myrtle:vectors} {item 1 snappy:vectors item 3 myrtle:vectors}
90

down dn

Takes:   degrees (number)

Returns:   none

Tilts the calling turtle’s nose down by the given number of degrees. See up

down 45

drift

Takes:   steps vector

Returns:   Causes the selected turtle to ‘drift’ the specified number of steps in the direction specified by vector. You can use drift to simulate momentum or gravity, particularly in concert with workers. See forwarddir

drift 10 forwarddir

forward 10 make "forward forwarddir newworker [repeat 5 [drift 1 :forward]]

dropanchor

Takes:   none

Returns:   none

Sets the selected turtle’s orbit anchor point to its current position. See setanchor

repeat 10 [penup forward 60 dropanchor pullout 50 pendown repeat 36 [orbitleft 10]]

encroaching

Takes:   position (list) | vectors (list) | [left right forward backward above below] (list)

Returns:   turtles (list)

Returns a list of turtles encroaching within the ‘box’ specified by the third list input. This is a more sophisticated version of inside, which allows for a box of any orientation, based on the provided vectors. See around, inside

show encroaching position vectors [10 10 10 10 10]

extrapolate

Takes:   position (list) | vector (list) | distance (number)

Returns:   list

Returns a list of target co-ordinates based on the starting position, a vector and the distance in turtle-units along that vector.

show extrapolate position forwarddir 5

face

Takes:   position (list of 3) | position (list of 3)

Returns:   vector (list)

face takes two lists of co-ordinates (x, y and z) and then returns a list of vectors (list of three lists of three) which if applied to a turtle cause it to ‘face’ the second set of co-ordinates if positioned at the first set of co-ordinates.

setvectors face position [100 100 100]

facingp

Takes:   boolean

Returns:   co-ordinates (list) | degrees (number)

boolean

returns true if a vector from the calling turtle to the supplied co-ordinates diverges less than the supplied number of degrees from the calling turtle's forward vector. See divergence

reset
snappy:show facingp myrtle:position 10
true

myrtle:show facingp snappy:position 10
false

fence

Takes:   none

Returns:   none

Causes the calling turtle to halt if it reaches the screen boundaries set by setbounds. See setbounds, bounds, window, wrap, caught

fence

fixate fix

Takes:   position

Returns:   none

Both sets the anchor point and points the selected turtle at it. Compare with setanchor, which does not change the orientation of the selected turtle.

snappy:fixate myrtle:position

fixate [0 0 0]

points Snappy (the camera turtle) at Myrtle.

forward fd

Takes:   turtle-spaces (number)

Returns:   none

Moves the turtle forward the given number of turtle steps. Draws a line if the pen is down. See pendown, back

forward 20

forwarddir

Takes:   none

Returns:   vector (list)

Returns the calling turtle’s forward vector.

show forwarddir

heading hd

Takes:   none

Returns:   degrees

Returns the heading (x-axis) of the selected turtle in degrees. Heading is an accumulated, relative value that cannot be used in isolation to accurately reproduce an orientation when the turtle moves in three dimensions – for that, use orientation / setorientation. See pitch and roll

print heading

home

Takes:   none

Returns:   none

Returns the currently selected turtle to the home position.

home

inside

Takes:   [[x1 y1 z1] [x2 y2 z2]]

Returns:   list

Returns a list of turtles inside the area denoted by the provided sets of co-ordinates.

show inside [[-100 -100 -100] [100 100 100]
[myrtle]

jump

Takes:   steps (number)

Returns:   none

Moves the turtle forward the given number of turtle steps without drawing, regardless of the pen state.

jump 20

left lt

Takes:   degrees

Returns:   none

Turns the selected turtle to the left the specified number of degrees. See right

left 90
lt 45

leftarc larc

Takes:   degrees or [degrees segments] | radius

Returns:   none

Creates an arc forward and to the left from the turtle’s position, placing the turtle at its end. Arcs do not wrap across borders tidily in wrap mode. If the first parameter is specified as a list, the first value in the list is the degrees, the second is the number of segments in the arc to be created, which overrides the internal algorithm used to calculate the number of segments. See leftmarc, rightarc

leftarc 90 40

leftmarc lmarc

Takes:   degrees | radius

Returns:   none

Creates an arc forward and to the left from the turtle’s position using the mark primitive, placing the turtle at its end. See rightmarc.

leftmarc 90 40

location

Takes:   co-ordinates (list)

Returns:   list

Returns a list of isRight, isAbove, isAhead where a value of 1 indicates the target co-ordinates are in those areas relative to the turtle’s forward view, 0 indicates that the co-ordinates are on the same plane as the calling turtle as appropriate, and -1 indicates the co-ordinates are in the opposite region (eg a -1 for isRight indicates it is to the left of the turtle’s forward vector / view).

snappy:show location myrtle:position
[0 0 1]

myrtle:show location snappy:position
[0 1 0]

lower lo

Takes:   turtle-units

Returns:   none

‘Lowers’ the turtle (moves back along its up vector). Same as doing ‘down 90 forward turtle-units up 90’. For example, Myrtle in her home position when turtleSpaces is started will move away from the Snappy camera turtle if you lower her. See raise

lower 100

move

Takes:   distance (turtle-units) | degrees OR [degrees degrees]

Returns:   none

Moves the turtle in the specified direction the specified number of turtle-units without altering its orientation or vectors. If a list of two values is specified, moves both left-right (first value) and up-down (second value) in that order.

move 20 45
move 20 [45 45]
repeat 3600 [move repcount / 1000 repcount]

near

Takes:   position (list) | radius (number)

Returns:   list

Returns a list of all the turtles within the specified radius of turtle-units from the specified position. See nearme

show near [0 0 0] 10

nearme

Takes:   distance (number)

Returns:   turtles (list)

Returns a list of turtles within the specified distance of the calling turtle, except the calling turtle itself. See near, nearp

show nearme 200

noautoorbit

Takes:   none

Returns:   none

Turns off any existing autoorbit. See autoorbit.

noautoorbit

nostealth

Takes:   none

Returns:   none

Causes calling turtle to appear in lists generated by near. See stealth

nostealth

notether

Takes:   none

Returns:   none

Untethers the selected turtle from the orbit anchor point. When the turtle is untethered, the anchor point moves relative to it.

notether

orbitdistance

Takes:   none

Returns:   turtle-units (number)

Returns the distance between a turtle and its anchor point. See setanchor, dropanchor

show orbitdistance

orbitdown odn

Takes:   degrees (number)

Returns:   none

Orbits down from (beneath) the turtle around its anchor point the specified number of degrees. Note that the turtle goes to its destination directly regardless of the status of fluid, and if the pen is down a line will be drawn between the start and destination with no intermediary points. See setanchor, dropanchor

orbitdown 90

orbitleft olt

Takes:   degrees (number)

Returns:   none

Orbits the turtle left around its anchor point the specified number of degrees. Note that the turtle goes to its destination directly regardless of the status of fluid, and if the pen is down a line will be drawn between the start and destination with no intermediary points. See setanchor, dropanchor

orbitleft 90

orbitright ort

Takes:   degrees (number)

Returns:   none

Orbits the turtle right around its anchor point the specified number of degrees. Note that the turtle goes to its destination directly regardless of the status of fluid, and if the pen is down a line will be drawn between the start and destination with no intermediary points. See setanchor, dropanchor

orbitup oup

Takes:   degrees (number)

Returns:   none

Orbits up from (above) the turtle around its anchor point the specified number of degrees. Note that the turtle goes to its destination directly regardless of the status of fluid, and if the pen is down a line will be drawn between the start and destination with no intermediary points. See setanchor, dropanchor

orbitup 90

orbitvector

Takes:   vector (list) | degrees (number)

Returns:   none

Orbits the specified number of degrees around the turtle’s anchor point using the specified vector. To orbit in the opposite direction, specify a negative number of degrees. Note that the turtle goes to its destination directly regardless of the status of fluid, and if the pen is down a line will be drawn between the start and destination with no intermediary points. See setanchor, dropanchor

orbitvector updir 10

orientation

Takes:   none

Returns:   list

Returns the current orientation, in the order specified by orientationorder. So if orientation order is set to “phr, then the first value returned by orientation will be pitch, the second heading and the third roll. See orientationorder

show orientation

orientationorder

Takes:   none

Returns:   word

Returns the current order heading, pitch and roll are processed when setorientation, setheading, setpitch or setroll is used.

show orientationorder
"hpr

origin

Takes:   none

Returns:   list

Returns the current origin co-ordinates. See setorigin, home

show origin
[0 0 0]

originvectors

Takes:   none

Returns:   list

Returns the current origin vectors. See setoriginvectors, origin, home

show originvectors

pitch pt

Takes:   none

Returns:   pitch (number)

Returns the pitch (attitude) of the current turtle

print pitch

pos

Takes:   none

Returns:   [x y] (list)

Returns the x and y co-ordinates of the turtle. For all three dimensions, use position

show pos

position

Takes:   none

Returns:   [x y z] (list)

Returns the co-ordinates of the turtle. For just the first two dimensions, use pos

show position

pullin pui

Takes:   turtle-spaces (number)

Returns:   none

Pulls the calling turtle toward its anchor point the specified number of turtle-spaces. Stops if it reaches its anchor point.

pullin 40

pullout puo

Takes:   turtle-spaces (number)

Returns:   none

Pulls the calling turtle out away from its anchor point the specified number of turtle-spaces.

dropanchor repeat 20 [penup pullout 10 pendown repeat 36 [orbitleft 10]]

raise ra

Takes:   turtle-units (number)

Returns:   none

Raises (elevates) the currently selected turtle by the specified number of turtle-units. Draws a line if the pen is down. See lower

raise 20

randomvectors randvec

Takes:   none

Returns:   none

Orients the currently selected turtle randomly in three dimensions. This does NOT alter the current pitch, heading or roll values.

pendown repeat 10 [randomvectors fd 100 home]

right rt

Takes:   degrees

Returns:   none

Turns the selected turtle the specified number of degrees to the right. If the specified number of degrees is negative, turns it to the left. See left

right 90

rightarc rarc

Takes:   degrees or [degrees segments] | radius

Returns:   none

Creates an arc forward and to the right from the turtle’s position, placing the turtle at its end. Arcs do not wrap properly across borders in wrap mode. If a list is provided for the first parameter, the second item in the list specifies the number of segments to be used in the construction of the rarc. See leftarc, rightmarc.

rightarc 90 40

rightmarc rmarc

Takes:   degrees | radius

Returns:   none

Creates an arc forward and to the right from the turtle’s position using the mark primitive, placing the turtle at its end. See leftmarc.

rightmarc 90 40

rightdir

Takes:   none

Returns:   vector

Returns the right vector of the selected turtle.

show rightdir

roll ro

Takes:   none

Returns:   number

Returns the current roll value. See setroll

show roll

rollleft rl

Takes:   degrees (number)

Returns:   none

Rolls the currently selected turtle to the left by the provided number of degrees.

rollleft 90

rollright rr

Takes:   degrees (number)

Returns:   none

Rolls the currently selected turtle to the right by the provided number of degrees.

rollright 45

setanchor

Takes:   position

Returns:   none

Sets the selected turtle’s orbit anchor to the specified three-dimensional position. Compare with fixate.

setanchor [0 0 0]

setbarriers

Takes:   [[[x1 y1 z1][x2 y2 z2]][[x3 y3 z3][x4 y4 z4]]…] (list of lists)

Returns:   none

Sets barriers on the calling turtle. The calling turtle cannot venture into the defined area(s). See barriers

setbarriers [[[0 0 0][100 100 100]]]

setbounds sbds

Takes:   x1 y1 x2 y2 (list) OR [[x1 y1 z1][x2 y2 z2]] (list of lists) OR radius

Returns:   none

Sets the boundary used by wrap and fence. If a single value is provided, the boundary is the radius of a circle / sphere. If a negative single value is provided, the boundary is a hemisphere laid on Z — that is, the turtle cannot travel into negative Z values. If no Z values are provided, sets them to -1000 / 1000. See bounds, fence, wrap

setbounds [-100 -100 100 100]
setbounds [[-100 -100 -100][100 100 100]

setheading seth shd

Takes:   degrees (number)

Returns:   none

Sets the turtle’s heading (left-right) and updates its orientation appropriately. Be aware that while setheading will alter the value of heading for the purposes of orientation, setorientation may not restore the expected turtle orientation if setheading is used in isolation. If you intend to use setorientation to restore a turtle’s orientation, you should use setorientation to change aspects of a turtle’s orientation also. See orientation

setheading 90

setorbitdistance

Takes:   turtle-units (number)

Returns:   none

Sets the currently selected turtle’s distance from its anchor point.

setorbitdistance 100

setorientation

Takes:   vectors (list)

Returns:   none

First unwinds the current orientation in the reverse of orientationorder, then changes the calling turtle’s orientation in the order specified by orientationorder, so that if orientationorder is “PHR then the first orientation changed is pitch, then heading, then the roll. Due to the nature of 3D movements, setorientation can only be used to restore orientations that are the result of relatively simple transforms (that is, series of orientation changing commands such as rollright or down). To restore complex orientations, use both setorientation and setvectors. See setvectors

setorientation [0 90 0]

setorientationorder

Takes:   order (word)

Returns:   none

Sets the order in which heading, pitch and roll are processed after using setheading, setpitch or setroll. The required word is a three letter combination made up of h, for heading, p, for pitch, and r, for roll. See orientationorder

setorientationorder "hpr
setorientationorder "rhp

setorigin

Takes:   [x y z] (list)

Returns:   none

Sets the turtle’s origin, the location it goes when it goes home. See origin, home

setorigin [50 50 50]

setoriginvectors

Takes:   vectors (list)

Returns:   none

Sets the turtle’s origin vectors, the orientation the turtle ends up in when it goes home. See originvectors, vectors, home

setoriginvectors vectors

setpitch setp spi

Takes:   degrees (number)

Returns:   none

Sets the turtle’s pitch (up-down) and updates its orientation appropriately. Be aware that while setpitch will alter the value of pitch for the purposes of orientation, setorientation may not restore the expected turtle orientation if setpitch is used in isolation. If you intend to use setorientation to restore a turtle’s orientation, you should use setorientation to change aspects of a turtle’s orientation also. See orientation

setpitch 180

setpos spo

Takes:   [x y] (list)

Returns:   none

Sets the x and y co-ordinates of the calling turtle’s position. If the pen is down, a line is drawn between the turtle’s old position and new position. Does not affect z. Exists for compatibility with two-dimensional logos.

setpos [20 30]

setposition spn

Takes:   [x y z] (list)

Returns:   none

Sets the turtle’s co-ordinates. If the pen is down, a line is drawn between the turtle’s old position and its new position.

pendown repeat 100 [setposition {-200 + random 400 -200 + random 400 -200 + random 400}]

setroll setr sro

Takes:   degrees (number)

Returns:   none

Sets the turtle’s roll (rollleft-rollright) and updates its orientation appropriately. Be aware that while setroll will alter the value of roll for the purposes of orientation, setorientation may not restore the expected turtle orientation if setroll is used in isolation. If you intend to use setorientation to restore a turtle’s orientation, you should use setorientation to change aspects of a turtle’s orientation also. See orientation

setroll 90

setvectors

Takes:   [[forwarddir] [updir] [rightdir]] (list of lists)

Returns:   none

Sets the current turtle’s orientation using vectors.

setvectors [1 -1 0] [1 1 1] [0 0 0]

setx

Takes:   number

Returns:   none

Sets the turtle’s x position.

setx 100

setxy

Takes:   x (number) | y (number)

Returns:   none

Sets the turtle’s x and y co-ordinates. This is here for compatibility. As opposed to setpos, which takes the two co-ordinates as a list. See setpos

setxy 10 20

sety

Takes:   number

Returns:   none

Sets the turtle’s y position.

sety 20

setz

Takes:   number

Returns:   none

Sets the turtle’s z position.

setz 50

showme

Takes:   turtle

Returns:   none

Causes the calling turtle to position itself in the default view turtle position over the specified turtle. Usually called by the current view (camera) turtle.

showme "myrtle

slideleft sl

Takes:   turtle-steps

Returns:   none

‘Slides’ the turtle to the left the given number of turtle-steps.

slideleft 20

slideright sr

Takes:   turtle-steps

Returns:   none

‘Slides’ the turtle to the right the given number of turtle-steps.

slideright 30

spin

Takes:   [vectors] (list) | degrees

Returns:   Spins the turtle around the given vector by the given number of degrees in a clockwise direction from behind the vector such that SPIN FORWARDDIR 90 would be the same as ROLLRIGHT 90. Does not affect pitch, heading or roll.

spin forwarddir 90

stealth

Takes:   none

Returns:   none

Causes the calling turtle not to appear in lists returned by near. See nostealth

stealth

tether

Takes:   none

Returns:   none

Tethers the selected turtle to the orbit anchor point. If the turtle moves, the anchor point remains unchanged. See setanchor, notether

tether

towards

Takes:   [x y] (list)

Returns:   heading (number)

Returns a heading that would make the turtle face toward the provided co-ordinates. towards assumes the target co-ordinate is on the same Z plane as the turtle. towards is a legacy Apple Logo primitive that is useful in turtleSpaces for compatibility and two-dimensional applications. See heading

setheading towards [30 40]

up

Takes:   degrees

Returns:   none

Angles the ‘nose’ of the turtle up the specified number of degrees. If looking down at the turtle from above (the default view), up 90 will cause the turtle to point straight up towards you.

up 90

updir

Takes:   none

Returns:   vector (list)

Returns the calling turtle’s current up vector. See rightdir, forwarddir

show updir

unproject

Takes:   position (list)

Returns:   [x-percent y-percent (list)

Returns the 2D position of the object as a percentage of the window / screen. For example, if the turtle appears to be in the dead center of the screen, unproject will return 50% across and 50% down. Note: If the co-ordinate is not in the view of the camera, unproject will return spurious results!

unproject myrtle:position

vectors

Takes:   none

Returns:   [forwarddir updir rightdir]

Returns the orientation vectors of the turtle as a list. This is the most reliable method of storing and restoring the orientation of a turtle, as opposed to the orientation function, which returns relative heading / pitch / roll values.

print vectors

xcor xpos

Takes:   none

Returns:   xpos (number)

Returns the current x co-ordinate of the turtle.

show xpos

ycor ypos

Takes:   none

Returns:   ypos (number)

Returns the current y co-ordinate of the turtle.

show ypos

zcor zpos

Takes:   none

Returns:   zpos (number)

Returns the current z co-ordinate of the turtle.

show zpos

zeroheading

Takes:   none

Returns:   none

Zeroes the turtle’s heading value. This does not modify the turtle’s orientation. Further changes will modify heading as appropriate. This primitive allows you to establish a new base heading value to work forward from. See heading

zeroheading

zeroorientation

Takes:   none

Returns:   none

Zeroes the turtle’s orientation values (pitch, heading, roll). This does not modify the turtle’s actual orientation. Further changes will modify orientation values as appropriate. This primitive allows you to establish new base orientation values to work forward from. See orientation

zeroorientation

zeropitch

Takes:   none

Returns:   none

Zeroes the turtle’s pitch value. This does not modify the turtle’s orientation. Further changes will modify pitch as appropriate. This primitive allows you to establish a new base pitch value to work forward from. See pitch

zeropitch

zeroroll

Takes:   none

Returns:   none

Zeroes the turtle’s roll value. This does not modify the turtle’s orientation. Further changes will modify roll as appropriate. This primitive allows you to establish a new base roll value to work forward from. See roll

zeroroll

zoom

Takes:   none

Returns:   number

Returns the turtle’s ‘zoom’ value, which is relevant to its display when it is a view turtle. 100 (as in 100%) is the default value. See setzoom

show zoom