learn libgdx kotlin

# Gamedev basics - libgdx - draw a rectangle

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This is a simple guide that allows to to draw a single rectangle on the screen.

Drawing rectangle is as simple as

```

renderer.rect(100f, 100f, 20f, 20f)

```

Programming games and animations could be started without IT or programming skills. These skills will be developed along the journey.

Here is step-by-step guide, how to start with game programming.

Guide is separated in 3 main sections:

1. Preparation: software and tools.

1. Running and troubleshooting.

1. Experiments.

## Preparation: software and tools

### Install

* git

* java 21

* intellij community edition

### In idea, download the project from github

![](clipboard-202501032023-dvwme.png)

URL: https://github.com/petrukhnov/libgdx-kotlearn

Agree to import it as gradle project. If it doesn't import, refresh manually:

![](clipboard-202501032023-uqp6s.png)

## Running and troubleshooting

### Run the project

![](clipboard-202501032023-nm2ql.png)

It should open new window with green background and white rectangle:

![](clipboard-202501032023-t8vno.png)

If it is not shown, see steps below to troubleshoot.

### If doesn't work

#### Java version is not found

![](clipboard-202501032024-egamk.png)

Select jdk 21, or download if missing.

manually select it:

![](clipboard-202501032024-aq4d5.png)

## Experiments

Here are few things to try.

### Change one of the values inside rect() function

```

Main:29

shapeRenderer.rect(100f, 200f, 30f, 30f)

```

Rerun and observe how shape changed.

### Change rectangle color

E.g. add on line 28 `shapeRenderer.color = Color(1f, 0f, 0f, 1f)`

### Change background color