APDL Eductation Resources/APDL Eductation Resources.iso/programs/graphics/d_turtle/!D_Turtle/Help

Text File | 1994-11-04 | 5.8 KB | 375 lines

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Supported functions:

PI - can be used to represent the
mathematical constant pi.

RND - used to generate random
numbers. Number MUST be enclosed
in brackets:

eg MAKE A RND(100) will create a
variable called A, and make it a
random number between 1 and 100.

COS & SIN - also supported,
angles in radians not degrees.

NB. Functions MUST be in capitals.
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General Information

The middle of the screen is
476 units across and 340 units up.

The bottom left position is 0,0.

The screen drawing area is 952x680
units.

No screen wrap is used so the
turtle can move off the edge of
the screen.
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BACK command:

Can be shortened to BK. Will move
the turtle in the opposite
direction it is facing.

Syntax:

1. BK <number> eg BK 250
2. BK <expression> eg BK 300/30
3. BK <variable> eg BK length
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CLEAN command:

Will cause all of the drawing
area to be erased. The turtle is
moved to the middle of the drawing
area.
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END command:

This command is used with the
REPEAT command. All of the
instructions between them will be
repeated.

For example
 REPEAT 4
 FD 200
 RT 90
 END

See the REPEAT command also.
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FILL command:

Using this instruction will fill
in the shape the turtle is inside.

If the turtle is not inside a
shape then the whole screen will
be filled.

Colours can be changed using the
SETCOLOUR command.
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FLIPX command:

FLIPX is used to flip the current
sprite about the x-axis.

Syntax: FLIPX
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FLIPY command:

FLIPY is used to flip the current
sprite about the y-axis.

Syntax: FLIPY
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FORWARD command:

Can be shortened to FD. Will move
the turtle forward in the current
direction.

Syntax:
1. FD <number> eg FD 250
2. FD <expression> eg FD 300/30
3. FD <variable> eg FD length
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HIDE command:

This command is used to hide the
turtle from view.

See also the SHOW command.

Syntax:

HIDE
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HOME command:

This command will move the turtle
to the middle of the screen and
set the turtle pointing straight
up (0 degrees).

Drawings on screen will be left as
they are.

Syntax:

HOME
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LEFT command:

Can be shortened to LT. Turns the
turtle to its left in degrees.


Syntax:

1. LT <number> eg LT 90
2. LT <expression> eg LT 360/30
3. LT <variable> eg LT angle
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LOAD command:

This command is used to load a
new sprite.

Syntax: LOAD <name> where <name>
is the name of the new sprite
you wish to load.
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MAKE command:

The MAKE command is used to set
up variables.

Syntax:
1. MAKE <variable> <number>
2. MAKE <variable> <expression>
3. MAKE <variable> <variable>

Example: MAKE length 250
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PENDOWN command:

Puts the turtle's pen down on the
page. This means the turtle will
leave a trail behind as it moves
around.

Use the PENUP command to stop
drawing as you move.
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PENUP command:

Will 'lift' the turtle's pen off
the page. This means no trail will
be left behind as the turtle moves
around.

Use the PENDOWN command to start
drawing again.
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REPEAT command:

This will cause all of the
instructions between the REPEAT
and an END command to be repeated.

Syntax:
1. REPEAT <number> eg REPEAT 5
2. REPEAT <expression>
3. REPEAT <variable> eg REPEAT number
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RIGHT command:

Can be shortened to RT. Turns the
turtle to its right in degrees.

Syntax:
1. RT <number> eg RT 250
2. RT <expression> eg RT 300/30
3. RT <variable> eg RT length
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SETCOLOUR command:

Can be shortened to SC.

This command is used to change the
colour the turtle will draw or
fill in.

Syntax:
1. SC <number>
2. SC <expression>
3. SC <variable>

The value of the number depends on
the current screen mode. To see
how many colours you have see the
Colours entry on the main menu.
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SETHEADING command:

Can be shortened to SH.

This command will force the turtle
to point in the new direction.

Syntax: SETHEADING <angle>
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SETNIB command:

Use this command to set the
thickness of the pen (1 is the
default value).

Syntax: SETNIB <number>
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SETPITCH command:

Causes the sound effect to be
replayed at a faster or slower
rate - changing the pitch.

Syntax:
1. SETPITCH <number>
2. SETPITCH <expression>
3. SETPITCH <variable>

The values should be in the
range -10 to 10 (0 is the
default).

eg SETPITCH 0 is normal
   SETPITCH 5 is faster
   SETPITCH -3 is slower
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SETSIZE command:

Use this command to set the size
of the current sprite when it is
put on screen.

Syntax: SETSIZE
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SETX command:

This command will set and move the
X (horizontal) position of the
turtle.

Syntax:
1. SETX <number> eg SETX 100
2. SETX <expression>
3. SETX <variable>

NB The heading of the turtle is
not changed.
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SETY command:

This command will set and move the
Y (vertical) position of the
turtle.

Syntax:
1. SETY <number> eg SETY 100
2. SETY <expression>
3. SETY <variable>

NB The heading of the turtle is
not changed.
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SHOW command:

Use this command to show the
turtle on screen.

See also the HIDE command.
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SOUND command:

Will cause the computer to produce
a sound effect.

Syntax: SOUND
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SPRITE command:

Draws the stored sprite onto the
screen at the turtle position.

Syntax: SPRITE
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SYMON command:

This command turns the symmetry
on.

Syntax: SYMON

Two axes of symmetry are placed
(invisibly) on the screen at the
centre point - one vertical and
one horizontal.

As the turtle draws, symmetrical
lines are drawn. Note that
sprites will NOT be affected by
this command.
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SYMOFF command:

This command turns the symmetry
off.

Syntax: SYMOFF
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TO command:

Used to create a procedure.

Syntax: TO <name> eg TO HEXAGON

The name of the procedure can
contain any combination of
characters (up to 10) you wish.
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WAIT command:

This command will make the
computer wait before doing its
next instruction.

WAIT 1 will cause it to wait one
second.

Syntax:
1. WAIT <number>
2. WAIT <expression>
3. WAIT <variable>
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WRITE command:

Causes text to be written onto
the screen.

Syntax:
WRITE "your text here"

NB You must put the speech marks
at the beginning and end of your
words.
EOF
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