Difference between revisions of "Activities/Turtle Art/Getting started"

Revision as of 00:58, 1 March 2011

Getting Started

Start by clicking on (or dragging) blocks from the Turtle palette. Use multiple blocks to create drawings; as the turtle moves under your control, colorful lines are drawn.

You add blocks to your program by clicking on or dragging them from the palette to the main area. You can delete a block by dragging it back onto the palette. Click anywhere on a "stack" of blocks to start executing that stack or by clicking in the Rabbit (fast) , Turtle (slow) or Bug (debug) buttons on the Project Toolbar.

The basics

Basic turtle graphics: 'forward', 'back', 'arc', and 'right' blocks
The 'set color' block affects pen trails, fill and text
'set pen size' block
Pen up and pen down

Drawing shapes

Use the repeat block to draw shapes
This can be generalised to n sided polygons, store n in Box1
Use 'start fill' and 'end fill' to draw filled shapes

Boxes, Stacks and the Heap

(aka variables, subroutines and the stack)

named variables:'store in' block
Named 'stacks' of blocks can be reused
Collapse a 'stack' of blocks to save space
Store data in the first in last out heap using 'push' and 'pop'
Box names (and stack names) can be boxes, in this case 10 boxes are created. This is a powerful programming feature. A one dimensional array of variables has been effectively created.

Displaying things

Using 'print'
'print' and 'show' can display numbers including results of calculations
'print' with text and numbers
'show' block used for text
'show' an image or video
'show' the camera output
'show' plays sounds as well

Keyboard, mouse and sensor input

Reading the keyboard
Converting the keyboard output to a string
Getting a multi digit number [[1]]
Load the Python block with the sample code push_mouse_event.py to read mouse events
Read the microphone
Read sensors plugged into the microphone socket [2]