Tag Archives: Python

Swing into action with an homage to Pitfall! | Wireframe #48

via Raspberry Pi

Grab onto ropes and swing across chasms in our Python rendition of an Atari 2600 classic. Mark Vanstone has the code

Whether it was because of the design brilliance of the game itself or because Raiders of the Lost Ark had just hit the box office, Pitfall Harry became a popular character on the Atari 2600 in 1982.

His hazardous attempts to collect treasure struck a chord with eighties gamers, and saw Pitfall!, released by Activision, sell over four million copies. A sequel, Pitfall II: The Lost Caverns quickly followed the next year, and the game was ported to several other systems, even making its way to smartphones and tablets in the 21st century.

Pitfall

Designed by David Crane, Pitfall! was released for the Atari 2600 and published by Activision in 1982

The game itself is a quest to find 32 items of treasure within a 20-minute time limit. There are a variety of hazards for Pitfall Harry to navigate around and over, including rolling logs, animals, and holes in the ground. Some of these holes can be jumped over, but some are too wide and have a convenient rope swinging from a tree to aid our explorer in getting to the other side of the screen. Harry must jump towards the rope as it moves towards him and then hang on as it swings him over the pit, releasing his grip at the other end to land safely back on firm ground.

For this code sample, we’ll concentrate on the rope swinging (and catching) mechanic. Using Pygame Zero, we can get our basic display set up quickly. In this case, we can split the background into three layers: the background, including the back of the pathway and the tree trunks, the treetops, and the front of the pathway. With these layers we can have a rope swinging with its pivot point behind the leaves of the trees, and, if Harry gets a jump wrong, it will look like he falls down the hole in the ground. The order in which we draw these to the screen is background, rope, tree-tops, Harry, and finally the front of the pathway.

Now, let’s get our rope swinging. We can create an Actor and anchor it to the centre and top of its bounding box. If we rotate it by changing the angle property of the Actor, then it will rotate at the top of the Actor rather than the mid-point. We can make the rope swing between -45 degrees and 45 degrees by increments of 1, but if we do this, we get a rather robotic sort of movement. To fix this, we add an ‘easing’ value which we can calculate using a square root to make the rope slow down as it reaches the extremes of the swing.

Our homage to the classic Pitfall! Atari game. Can you add some rolling logs and other hazards?

Our Harry character will need to be able to run backwards and forwards, so we’ll need a few frames of animation. There are several ways of coding this, but for now, we can take the x coordinate and work out which frame to display as the x value changes. If we have four frames of running animation, then we would use the %4 operator and value on the x coordinate to give us animation frames of 0, 1, 2, and 3. We use these frames for running to the right, and if he’s running to the left, we just mirror the images. We can check to see if Harry is on the ground or over the pit, and if he needs to be falling downward, we add to his y coordinate. If he’s jumping (by pressing the SPACE bar), we reduce his y coordinate.

We now need to check if Harry has reached the rope, so after a collision, we check to see if he’s connected with it, and if he has, we mark him as attached and then move him with the end of the rope until the player presses the SPACE bar and he can jump off at the other side. If he’s swung far enough, he should land safely and not fall down the pit. If he falls, then the player can have another go by pressing the SPACE bar to reset Harry back to the start.

That should get Pitfall Harry over one particular obstacle, but the original game had several other challenges to tackle – we’ll leave you to add those for yourselves.

Pitfall Python code

Here’s Mark’s code for a Pitfall!-style platformer. To get it working on your system, you’ll need to  install Pygame Zero.  And to download the full code and assets, head here.

Get your copy of Wireframe issue 48

You can read more features like this one in Wireframe issue 48, available directly from Raspberry Pi Press — we deliver worldwide.
Wireframe issue 48
And if you’d like a handy digital version of the magazine, you can also download issue 48 for free in PDF format.
A banner with the words "Be a Pi Day donor today"

The post Swing into action with an homage to Pitfall! | Wireframe #48 appeared first on Raspberry Pi.

Visual Studio Code comes to Raspberry Pi

via Raspberry Pi

Microsoft’s Visual Studio Code is an excellent C development environment, and now it’s an easy install on Raspberry Pi. Here’s Jim Bennett from Microsoft to show you all how to get VS Code up and running on our tiny computer. Take it away, Jim…

There are a few products in the tech sphere that get me really excited. One of them is Raspberry Pi (obviously), and the other is Visual Studio Code or VS Code. I always hoped that the two would come together one day — and now, to my great pleasure, they have!

VS Code is a free, open source developer text editor originally released for Windows, macOS and x64 Linux. Out of the box it supports generic text editing and git source code control, as well as full web development with JavaScript, TypeScript and Node.js, with debugging, intellisense and all the goodness you’d expect from a full-featured IDE. What makes it super powerful is extensions — bringing a huge range of programming languages, developer tools and other capabilities.

For example my VS Code setup includes a Python extension so I can code and debug in Python, a set of Microsoft Azure extensions so I can manage my cloud services, PlatformIO to allow me to program micro-controllers like Arduino boards coupled with a C++ extension to support coding in C and C++, and even some Docker support. Not a bad setup for a completely free developer tool.

Jim’s Raspberry Pi 400 running VS Code

I’ve been hoping for years VS Code would come to Raspberry Pi, and finally it’s here. As well as supporting Debian Linux on x64, there are now builds for ARM and ARM64 – both of which can run on Raspberry Pi OS (the ARM build on Raspberry Pi OS, the ARM64 on the beta of the 64-bit Raspberry Pi OS). And yes — I am writing this right now on a Raspberry Pi 400 running VS Code!

Why am I so excited about this?

Well, there are a couple of reasons.

Firstly, it brings an exceptional developer tool to Raspberry Pi. There are already some great editors, but nothing of the calibre of VS Code. I can take my $35 computer, plug it into a keyboard and mouse, connect a monitor and a TV and code in a wide range of languages from the same place.

I see kids learning Python at school using one tool, then learning web development in an after-school coding club with a different tool. They can now do both in the same application, reducing the cognitive load – they only have to learn one tool, one debugger, one setup. Combine this with the new Raspberry Pi 400 and you have an all-in-one solution to learning to code, reminiscent of my ZX Spectrum of decades ago, but so much more powerful.

The second reason is to me the most important — it allows kids to share the same development environment as their grown-ups. Imagine the joy of a 10-year-old coding Python using VS Code on their Raspberry Pi plugged into the family TV, then seeing their Mum working from home coding Python in exactly the same tool on her work laptop as part of her job as an AI engineer or data scientist. It also makes it easier when Mum has to inevitably help with unblocking the issues that always come up with learners.

As a young child it was mind-blowing when my Dad brought home a work PC so he could write reports and I could use it to write up my school work – I was using what Dad used at work, making me feel important. I see this with my seven-year-old daughter, seeing her excitement that I use Microsoft Teams for work, the same as she uses for her virtual schooling (she’s even offered to teach me how to use it if I get stuck). To be able to bring that unadulterated joy of using ‘grown-up tools’ to our young learners is priceless.

Installing VS Code

The great news is VS Code is now available as part of the Raspberry Pi OS apt packages. Launch the Raspberry Pi Terminal and run the following commands:

sudo apt update 
sudo apt install code -y

This will download and install VS Code. If you’ve got your hands on a Pico, then you may not even need to do this – VS Code is installed as part of the Pico setup from the Getting Started guide.

After installing VS Code, you can run it from the Programming folder in the Raspberry Pi menu.

Getting started with VS Code

VS Code may seem daunting at first – it’s a powerful tool with a huge range of extensions. The good news is Microsoft has you covered with lots of hands-on, self-guided learning guides on how to use it with different languages and development tools, from using Git version control, to developing web applications — there’s even a guide to learning Python basics with Wonder Woman.

Go grab it and happy coding!

Jim with his arms folded wearing a dark t shirt
There he is – that’s the real life Jim!

Brilliant Jim Bennett shares loads of Raspberry Pi builds and tutorials over on Expecting Someone Geekier and tweets @jimbobbennett. He also works in Developer Relations at Microsoft. You can learn pretty much everything there is to know about him on github.

The post Visual Studio Code comes to Raspberry Pi appeared first on Raspberry Pi.

Code a Light Cycle arcade minigame | Wireframe #47

via Raspberry Pi

Speed around an arena, avoiding walls and deadly trails in this Light Cycle minigame. Mark Vanstone has the code.

Battle against AI enemies in the original arcade classic.

At the beginning of the 1980s, Disney made plans for an entirely new kind of animated movie that used cutting-edge computer graphics. The resulting film was 1982’s TRON, and it inevitably sparked one of the earliest tie-in arcade machines.

The game featured several minigames, including one based on the Light Cycle section of the movie, where players speed around an arena on high-tech motorbikes, which leave a deadly trail of light in their wake. If competitors hit any walls or cross the path of any trails, then it’s game over.

Players progress through the twelve levels which were all named after programming languages. In the Light Cycle game, the players compete against AI players who drive yellow Light Cycles around the arena. As the levels progress, more AI Players are added.

The TRON game, distributed by Bally Midway, was well-received in arcades, and even won Electronic Games Magazine’s (presumably) coveted Coin-operated Game of the Year gong.

Although the arcade game wasn’t ported to home computers at the time, several similar games – and outright clones – emerged, such as the unsubtly named Light Cycle for the BBC Micro, Oric, and ZX Spectrum.

The Light Cycle minigame is essentially a variation on Snake, with the player leaving a trail behind them as they move around the screen. There are various ways to code this with Pygame Zero.

In this sample, we’ll focus on the movement of the player Light Cycle and creating the trails that are left behind as it moves around the screen. We could use line drawing functions for the trail behind the bike, or go for a system like Snake, where blocks are added to the trail as the player moves.

In this example, though, we’re going to use a two-dimensional list as a matrix of positions on the screen. This means that wherever the player moves on the screen, we can set the position as visited or check to see if it’s been visited before and, if so, trigger an end-game event.

Our homage to the TRON Light Cycle classic arcade game.

For the main draw() function, we first blit our background image which is the cross-hatched arena, then we iterate through our two-dimensional list of screen positions (each 10 pixels square) displaying a square anywhere the Cycle has been. The Cycle is then drawn and we can add a display of the score.

The update() function contains code to move the Cycle and check for collisions. We use a list of directions in degrees to control the angle the player is pointing, and another list of x and y increments for each direction. Each update we add x and y coordinates to the Cycle actor to move it in the direction that it’s pointing multiplied by our speed variable.

We have an on_key_down() function defined to handle changing the direction of the Cycle actor with the arrow keys. We need to wait a while before checking for collisions on the current position, as the Cycle won’t have moved away for several updates, so each screen position in the matrix is actually a counter of how many updates it’s been there for.

We can then test to see if 15 updates have happened before testing the square for collisions, which gives our Cycle enough time to clear the area. If we do detect a collision, then we can start the game-end sequence.

We set the gamestate variable to 1, which then means the update() function uses that variable as a counter to run through the frames of animation for the Cycle’s explosion. Once it reaches the end of the sequence, the game stops.

We have a key press defined (the SPACE bar) in the on_key_down() function to call our init() function, which will not only set up variables when the game starts but sets things back to their starting state.

Here’s Mark’s code for a TRON-style Light Cycle minigame. To get it working on your system, you’ll need to install Pygame Zero. And to download the full code and assets, head here.

So that’s the fundamentals of the player Light Cycle movement and collision checking. To make it more like the original arcade game, why not try experimenting with the code and adding a few computer-controlled rivals?

Get your copy of Wireframe issue 47

You can read more features like this one in Wireframe issue 47, available directly from Raspberry Pi Press — we deliver worldwide.

And if you’d like a handy digital version of the magazine, you can also download issue 47 for free in PDF format.

The post Code a Light Cycle arcade minigame | Wireframe #47 appeared first on Raspberry Pi.

Code your own Pipe Mania puzzler | Wireframe #46

via Raspberry Pi

Create a network of pipes before the water starts to flow in our re-creation of a classic puzzler. Jordi Santonja shows you how.

A screen grab of the game in motion
Pipe Mania’s design is so effective, it’s appeared in various guises elsewhere – even as a minigame in BioShock.

Pipe Mania, also called Pipe Dream in the US, is a puzzle game developed by The Assembly Line in 1989 for Amiga, Atari ST, and PC, and later ported to other platforms, including arcades. The player must place randomly generated sections of pipe onto a grid. When a counter reaches zero, water starts to flow and must reach the longest possible distance through the connected pipes.

Let’s look at how to recreate Pipe Dream in Python and Pygame Zero. The variable start is decremented at each frame. It begins with a value of 60*30, so it reaches zero after 30 seconds if our monitor runs at 60 frames per second. In that time, the player can place tiles on the grid to build a path. Every time the user clicks on the grid, the last tile from nextTiles is placed on the play area and a new random tile appears at the top of the next tiles. randint(2,8) computes a random value between 2 and 8.

Our Pipe Mania homage. Build a pipeline before the water escapes, and see if you can beat your own score.

grid and nextTiles are lists of tile values, from 0 to 8, and are copied to the screen in the draw function with the screen.blit operation. grid is a two-dimensional list, with sizes gridWidth=10 and gridHeight=7. Every pipe piece is placed in grid with a mouse click. This is managed with the Pygame functions on_mouse_move and on_mouse_down, where the variable pos contains the mouse position in the window. panelPosition defines the position of the top-left corner of the grid in the window. To get the grid cell, panelPosition is subtracted from pos, and the result is divided by tileSize with the integer division //. tileMouse stores the resulting cell element, but it is set to (-1,-1) when the mouse lies outside the grid.

The images folder contains the PNGs with the tile images, two for every tile: the graphical image and the path image. The tiles list contains the name of every tile, and adding to it _block or _path obtains the name of the file. The values stored in nextTiles and grid are the indexes of the elements in tiles.

wfmag46code
Here’s Jordi’s code for a Pipemania-style puzzler. To get it working on your system, you’ll need to install Pygame Zero. And to download the full code and assets, head here.

The image waterPath isn’t shown to the user, but it stores the paths that the water is going to follow. The first point of the water path is located in the starting tile, and it’s stored in currentPoint. update calls the function CheckNextPointDeleteCurrent, when the water starts flowing. That function finds the next point in the water path, erases it, and adds a new point to the waterFlow list. waterFlow is shown to the user in the draw function.

pointsToCheck contains a list of relative positions, offsets, that define a step of two pixels from currentPoint in every direction to find the next point. Why two pixels? To be able to define the ‘cross’ tile, where two lines cross each other. In a ‘cross’ tile the water flow must follow a straight line, and this is how the only points found are the next points in the same direction. When no next point is found, the game ends and the score is shown: the number of points in the water path, playState is set to 0, and no more updates are done.

Get your copy of Wireframe issue 46

You can read more features like this one in Wireframe issue 46, available directly from Raspberry Pi Press — we deliver worldwide.

wfcover

And if you’d like a handy digital version of the magazine, you can also download issue 46 for free in PDF format.

The post Code your own Pipe Mania puzzler | Wireframe #46 appeared first on Raspberry Pi.

Code your own Artillery-style tank game | Wireframe #44

via Raspberry Pi

Fire artillery shells to blow up the enemy with Mark Vanstone’s take on a classic two-player artillery game

Artillery Duel was an early example of the genre, and appeared on such systems as the Bally Astrocade and Commodore 64 (pictured).

To pick just one artillery game is difficult since it’s a genre in its own right. Artillery simulations and games have been around for almost as long as computers, and most commonly see two players take turns to adjust the trajectory of their tank’s turret and fire a projectile at their opponent. The earliest versions for microcomputers appeared in the mid-seventies, and the genre continued to develop; increasingly complex scenarios appeared involving historical settings or, as we saw from the mid-90s on, even offbeat ideas like battles between factions of worms.

To code the basics of an artillery game, we’ll need two tanks with turrets, a landscape, and some code to work out who shot what, in which direction, and where said shot landed. Let’s start with the landscape. If we create a landscape in two parts – a backdrop and foreground – we can make the foreground destructible so that when a missile explodes it damages part of the landscape. This is a common effect used in artillery games, and sometimes makes the gameplay more complicated as the battle progresses. In our example, we have a grass foreground overlaid on a mountain scene. We then need a cannon for each player. In this case, we’ve used a two-part image, one for the base and one for the turret, which means the latter can be rotated using the up and down keys.

Our homage to the artillery game genre. Fire away at your opponent, and hope they don’t hit back first.

For this code example, we can use the Python dictionary to store several bits of data about the game objects, including the Actor objects. This makes the data handling tidy and is quite similar to the way that JSON is used in JavaScript. We can use this method for the two cannons, the projectile, and an explosion object. As this is a two-player game, we’ll alternate between the two guns, allowing the arrow keys to change the angle of the cannon. When the SPACE bar is pressed, we call the firing sequence, which places the projectile at the same position as the gun firing it. We then move the missile through the air, reducing the speed as it goes and allowing the effects of gravity to pull it towards the ground.

We can work out whether the bullet has hit anything with two checks. The first is to do a pixel check with the foreground. If this comes back as not transparent, then it has hit the ground, and we can start an explosion. To create a hole in the foreground, we can write transparent pixels randomly around the point of contact and then set off an explosion animation. If we test for a collision with a gun, we may find that the bullet has hit the other player and after blowing up the tank, the game ends. If the impact only hit the landscape, though, we can switch control over to the other player and let them have a go.

So that’s your basic artillery game. But rest assured there are plenty of things to add – for example, wind direction, power of the shot, variable damage depending on proximity, or making the tanks fall into holes left by the explosions. You could even change the guns into little wiggly creatures and make your own homage to Worms.

Here’s Mark’s code for an artillery-style tank game. To get it working on your system, you’ll need to install Pygame Zero. And to download the full code and assets, head here.

Get your copy of Wireframe issue 44

You can read more features like this one in Wireframe issue 44, available directly from Raspberry Pi Press — we deliver worldwide.

And if you’d like a handy digital version of the magazine, you can also download issue 44 for free in PDF format.

Wireframe #44, bringing the past and future of Worms to the fore.

Make sure to follow Wireframe on Twitter and Facebook for updates and exclusive offers and giveaways. Subscribe on the Wireframe website to save up to 72% compared to newsstand pricing!

The post Code your own Artillery-style tank game | Wireframe #44 appeared first on Raspberry Pi.

New book: Create Graphical User Interfaces with Python

via Raspberry Pi

Laura Sach and Martin O’Hanlon, who are both Learning Managers at the Raspberry Pi Foundation, have written a brand-new book to help you to get more out of your Python projects.

Cover of the book Create Graphical User Interfaces with Python

In Create Graphical User Interfaces with Python, Laura and Martin show you how to add buttons, boxes, pictures, colours, and more to your Python programs using the guizero library, which is easy to use and accessible for all, no matter your Python skills.

This new 156-page book is suitable for everyone — from beginners to experienced Python programmers — who wants to explore graphical user interfaces (GUIs).

Meet the authors

Screenshot of a Digital Making at Home live stream session
That’s Martin in the blue T-shirt with our Digital Making at Home live stream hosts Matt and Christina

You might have met Martin recently on one of our weekly Digital Making at Home live streams for young people, were he was a guest for an ‘ooey-GUI’ code-along session. He talked about his background and what it’s like creating projects and learning resources on a day-to-day basis.

Laura is also pretty cool! Here she is showing you how to solder your Raspberry Pi header pins:

Hi Laura!

Martin and Laura are also tonnes of fun on Twitter. You can find Martin as @martinohanlon, and Laura goes by @codeboom.

10 fun projects

In Create Graphical User Interfaces with Python, you’ll find ten fun Python projects to create with guizero, including a painting program, an emoji match game, and a stop-motion animation creator.

A double-page from the book Create Graphical User Interfaces with Python
A peek inside Laura’s and Martin’s new book

You will also learn:

  • How to create fun Python games and programs
  • How to code your own graphical user interfaces using windows, text boxes, buttons, images, and more
  • What event-based programming is
  • What good (and bad) user interface design is
A double-page from the book Create Graphical User Interfaces with Python
Ain’t it pretty?

Where can I get it?

You can buy Create Graphical User Interfaces with Python now from the Raspberry Pi Press online store, or the Raspberry Pi store in Cambridge, UK.

And if you don’t need the lovely new book, with its new-book smell, in your hands in real life, you can download a PDF version for free, courtesy of The MagPi magazine.

The post New book: Create Graphical User Interfaces with Python appeared first on Raspberry Pi.