# Space Invaders – 3D Pixel Art

In this blog post we will use Glowscript to create a 3D animation of a space invader.

2D Graphics used in retro arcade games consist of pixels. A 2D graphic can be described as a grid of pixels of different colours.

In programming we can use a 2D array data structure to represent a graphic. In Python, 2D arrays are implemented using a list of lists.

In our code (see below) we have declared a 2D array called pixels to store the value of each pixel used to represent one of the space invaders.

```pixels   =   [[0,0,1,0,0,0,0,0,1,0,0]]
pixels.append([0,0,0,1,0,0,0,1,0,0,0])
pixels.append([0,0,1,1,1,1,1,1,1,0,0])
pixels.append([0,1,1,0,1,1,1,0,1,1,0])
pixels.append([1,1,1,1,1,1,1,1,1,1,1])
pixels.append([1,0,1,1,1,1,1,1,1,0,1])
pixels.append([1,0,1,0,0,0,0,0,1,0,1])
pixels.append([0,0,0,1,1,0,1,1,0,0,0])```

Using a 2 nested loops we then looped through each row and each column of this array to retrieve the value of each pixel in order to create the cubes needed to create a 3D model of a space invader.

We then create a compound object to join these cubes together in a single object. Finally using an infinite while loop we animate/rotate our invader around itself.

Here is our 3D animation: (Use Google Chrome to preview this animation)

Right Click on the animation to change the view point (rotate camera angle).

#### Find out more…

Create and animate all the different Space Invaders.

#### From 2D to 3D: Crossy Road Chicken

This technique of creating 2D graphics can also be used for 3D graphics. In this case a 3D array is used to store the pixels alongside 3 dimensions: x, y and z.

Let’s look at the code below used to create a 3D model of the chicken from the Crossy Road game:

Check in the code below to see how a list of lists of lists is used in Python to create a 3D array.

Also look at how, using 3 nested loops we can iterate through each “pixel” of the 3D array.

We have also used a 1D array called palette to store all the colours to be used in our 3D model.

Can you think of other games that might use 3D arrays?

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