# Lesson 3: Drawing in Game Lab

## Overview

Students are introduced to Game Lab, the programming environment for this unit, and begin to use it to position shapes on the screen. They learn the basics of sequencing and debugging, as well as a few simple commands. At the end of the lesson, students will be able to program images like the ones they made with the drawing tool in the previous lesson.

## Objectives

### Students will be able to:

• Use a coordinate system to place elements on the screen.
• Sequence code correctly to overlay shapes.

## Vocabulary

• Bug – Part of a program that does not work correctly.
• Debugging – Finding and fixing problems in an algorithm or program.
• Program – An algorithm that has been coded into something that can be run by a machine.

## Introduced Code

• `fill(color)`
• `ellipse(x, y, w, h)`
• `rect(x, y, w, h)`

## Warm Up (5 minutes)

### Programming Images

Goal From Unit 2, you may remember that a computer can only understand what to do if you use a particular language in order to communicate with it. For Web Development, that language was HTML. Computers can’t “figure out” what you mean in the same way that a human can, and they are usually much more specific in how they follow instructions.

In the last lesson we created images on the computer by organizing squares and circles on a grid. For each image you wanted to create, you had to lay those images out manually, and if you wanted to recreate an image it was a lot of work. Today, we’re going to program the computer to draw those images for us. Based on what you know about computers, what do you think will be different between telling a person about your image and telling a computer about your image?

In order to give instructions to a computer, we need to use a language that a computer understands. In the last unit, we used HTML, which is great for making web pages. To make our animations and games, we will use a version of Javascript that uses blocks. The environment that we’ll be programming in is called Game Lab.

## Activity (30 minutes)

Here are some things to remember when programming:

• One command per line
• Commands run in order from top to bottom
• Order of inputs into shape commands matter
• Each input into shape commands are separated by commas
• (0,0) is in the upper left corner of the display
• All x and y values on the display are positive

### Simple Drawing in Game Lab

Group: Get with a partner

Transition: Go to Code Studio.

## Wrap Up (10 minutes)

### Share Drawings

Goal: You get to see the variety of different things you can create with just simple shape drawings.

Share: Once you have completed your drawings share your drawings with the class with a gallery walk during the last 15 minutes of class today.

### Exit Ticket

Goal : Share tricks you learned as you went through the levels.

Prompt: Today you learned how to draw in Game Lab for the first time. What type of advice would you share with a friend who was going to learn about drawing in Game Lab to make it easier for them? Write it down on a piece of paper. Turn it in. I will share it with the class next time we meet.

DO THE LESSON 3 CHALLENGES