The first function release my Wumpus for Picosystem game is available now. It’s a variant of the classic Hunt the Wumpus game played on a grid with the display and controls designed for the Pimoroni PicoSystem. The GitHub release contains both the source code and the compiled binary UF2 file. While this isn’t yet what I’d consider a fully playable game, there are enough pieces implemented that it may benefit others looking for examples or inspiration.

The key functionality implemented is:

• Movement – the player can navigate a 10 x 10 grid using the directional pad.
• Shooting – the player can
  • Switch between movement and shooting modes using any of the X, Y, A, B buttons.
  • Shoot an arrow using the directional pad when in shooting mode.
• Bats – two caves contain bats which will randomly relocate the player.
• Pits – two caves contain pits, which will end the game if the player enters those caves.
• Wumpus – one cave contains the Wumpus, which will end the game if the player enters that cave.
• Animations – certain activities are animated:Movement between caves
  • Shooting arrows
  • Falling into a pit
  • Being carried by a bat
  • Being eaten by a Wumpus

The key pieces of infrastructure implemented are:

• States – the game is implemented as a finite state machine (E.G. FELL_IN_PIT_STATE, SHOOTING_STATE)
• Custom Sprites – custom spritesheet converted using sprite-converter-for-picosystem
• Win/Lose – the game does handle the notion of being over and restarting

Having gotten to the point of compiling the snake example in my previous post, it is time to move on to the hello world example in the guide on Pimoroni. The only initial change I made was naming my project hello_world instead of ourproject. After setting up the example code, I found I had some warnings and an error when trying to run cmake.

The first warning:

  No project() command is present.  The top-level CMakeLists.txt file must
  contain a literal, direct call to the project() command.  Add a line of
  code such as

    project(ProjectName)

  near the top of the file, but after cmake_minimum_required().

  CMake is pretending there is a "project(Project)" command on the first
  line.

I addressed this by adding the following line (based on looking at the PicoSystem SDK CMakeLists.txt file):

project(hello_world C CXX ASM)

The second warning:

CMake Warning (dev) in CMakeLists.txt:
  No cmake_minimum_required command is present.  A line of code such as

    cmake_minimum_required(VERSION 3.16)

  should be added at the top of the file.  The version specified may be lower
  if you wish to support older CMake versions for this project.  For more
  information run "cmake --help-policy CMP0000".

I addressed this by adding the following line (again, based on looking at the PicoSystem SDK CMakeLists.txt file):

cmake_minimum_required(VERSION 3.12)

Finally, the error:

CMake Error at CMakeLists.txt:14 (pico_add_extra_outputs):
  Unknown CMake command "pico_add_extra_outputs".


-- Configuring incomplete, errors occurred!

I addressed this by doing three things. First, I copied pico-sdk/external/pico_sdk_import.cmake to my project directory hello_world. Second, I added these lines to my CMakeLists.txt file:

# Pull in PICO SDK (must be before project)
include(pico_sdk_import.cmake)

# ...

find_package(PICOSYSTEM REQUIRED)

Finally, I used the following cmake command:

cmake -DPICOSYSTEM_DIR:PATH=~/picosystem ..

This got me to a point where I can run cmake without warnings or errors; however, running make does result in errors:

/vagrant/hello_world/hello_world.cpp: In function 'void draw()':
/vagrant/hello_world/hello_world.cpp:12:3: error: 'pen' was not declared in this scope; did you mean 'picosystem::pen'?
   12 |   pen(0, 0, 0);
      |   ^~~
      |   picosystem::pen
In file included from /vagrant/hello_world/hello_world.cpp:1:
/home/vagrant/picosystem/libraries/picosystem.hpp:49:15: note: 'picosystem::pen' declared here
   49 |   void        pen(color_t p);
      |               ^~~
/vagrant/hello_world/hello_world.cpp:13:3: error: 'clear' was not declared in this scope; did you mean 'picosystem::clear'?
   13 |   clear();
      |   ^~~~~
      |   picosystem::clear
In file included from /vagrant/hello_world/hello_world.cpp:1:
/home/vagrant/picosystem/libraries/picosystem.hpp:57:15: note: 'picosystem::clear' declared here
   57 |   void        clear();
      |               ^~~~~
/vagrant/hello_world/hello_world.cpp:16:3: error: 'text' was not declared in this scope; did you mean 'picosystem::text'?
   16 |   text("Hello, world!", 0, 0);
      |   ^~~~
      |   picosystem::text
In file included from /vagrant/hello_world/hello_world.cpp:1:
/home/vagrant/picosystem/libraries/picosystem.hpp:78:15: note: 'picosystem::text' declared here
   78 |   void        text(const std::string &t);
      |               ^~~~
make[2]: *** [CMakeFiles/hello_world.dir/build.make:63: CMakeFiles/hello_world.dir/hello_world.cpp.obj] Error 1
make[1]: *** [CMakeFiles/Makefile2:1544: CMakeFiles/hello_world.dir/all] Error 2
make: *** [Makefile:84: all] Error 2

I addressed this by adding the following to hello_world.cpp (based on snake.cpp):

using namespace picosystem;

Which got to the next error:

/usr/lib/gcc/arm-none-eabi/9.2.1/../../../arm-none-eabi/bin/ld: CMakeFiles/hello_world.dir/home/vagrant/picosystem/libraries/picosystem.cpp.obj: in function `main':
picosystem.cpp:(.text.startup.main+0xf8): undefined reference to `update(unsigned long)'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/hello_world.dir/build.make:852: hello_world.elf] Error 1
make[1]: *** [CMakeFiles/Makefile2:1544: CMakeFiles/hello_world.dir/all] Error 2
make: *** [Makefile:84: all] Error 2

Which I addressed by changing the signature of the update method like so:

void update(uint32_t tick) {
}

At this point, I was able to compile and produce a uf2 file. I’m including the current working version of my files below in case they are useful to others:

CMakeLists.txt

cmake_minimum_required(VERSION 3.12)

# Pull in PICO SDK (must be before project)
include(pico_sdk_import.cmake)

project(hello_world C CXX ASM)

find_package(PICOSYSTEM REQUIRED)

add_definitions(-DPIXEL_DOUBLE)

add_executable(
  hello_world
  hello_world.cpp
)

target_link_libraries(hello_world picosystem)

pico_add_extra_outputs(hello_world)

hello_world.cpp:

#include "picosystem.hpp"

using namespace picosystem;

void init() {

}

void update(uint32_t tick) {

}

void draw() {
  pen(0, 0, 0);
  clear();

  pen(15, 15, 15);
  text("Hello, world!", 0, 0);
}

In the second post on Cistercian Numbers, I covered drawing the Cistercian numeral five using ucblogo (Berkeley Logo). Six through nine was left as a future exercise since the numeral for six is a new primitive:

In this post, we’ll cover drawing the numerals six through nine which will round out the single digits.