matt-dray/safar6

:footprints::ox: R package: a playable text-based simulation of Pokémon's Safari Zone using {R6}

safar6

Summary

An R package containing an R6 class to simulate simplified gameplay elements of the Safari Zone sub-area from Pokémon Blue (1998) with OOP.

The first generation of Pokémon games were developed for the Nintendo Game Boy by Game Freak and published by Nintendo. Pokémon as a property is owned by The Pokémon Company.

This project is a demonstration of the {R6} package and the R6-class for object-oriented programming in R. It’s purely for learning purposes. You can read a blog post about it.

Basic gameplay

Install from GitHub with remotes::install_github("matt-dray/safar6").

The game is text-based and takes place entirely in the console. Start a game like x <- safar6::safari_zone$new(). Be warned: it’s tricky. But then so was the original.

Use x$step() to take a step through the tall grass of the Safari Zone. There’s a chance you’ll encounter a wild Pokémon; perhaps it will be a rare one at a high level. You’ll be prompted to throw a Safari Ball to try and catch it, with the option to throw bait or a rock to influence its catchability. Try to catch as many Pokémon as you can before you run out of steps or balls.

Use x$pause() to ‘pause’ the game and see your current stats. You can boot up x$bills_pc to see which Pokémon you’ve caught so far.

For help with fields and methods see ?safar6::safari_zone.

Expand for (contrived) example gameplay 👾

> library(safar6)
# {safar6}
# Start game: x <- safari_zone$new()
# Take a step: x$step()
> x <- safari_zone$new()
# ------------------------
# First, what is your name?
# NEW NAME (1)
# BLUE (2)
# GARY (3)
# JOHN (4)
# ------------------------
# Select 1, 2, 3 or 4:
> 1
# Your name: 
> THEW
# Welcome to the SAFARI ZONE!
# For just P500, you can catch all the
# Pokemon you want in the park!
# Would you like to join the hunt?
# ------------------------
# MONEY: P500
# YES (1) or NO (2)
# ------------------------
# Select 1 or 2: 
> 1
# That'll be P500 please!
# ------------------------
# MONEY: P0
# ------------------------
# We only use a special POKe BALL here.
# THEW received 30 SAFARI BALLs!
# We'll call you on the PA when you run out of time or SAFARI BALLs!
> x$step()
# 499/500
> x$step()
# 498/500
> x$step()
# 497/500
# Wild VENONAT L22 appeared!
# ------------------------
# BALLx30 (1)     BAIT (2)
# THROW ROCK (3)  RUN (4)
# ------------------------
# Selection: 
> 3
# THEW threw a ROCK.
# Wild VENONAT is angry!
# ------------------------
# BALLx30 (1)     BAIT (2)
# THROW ROCK (3)  RUN (4)
# ------------------------
# Select 1, 2, 3 or 4: 
> 1
# THEW used SAFARI BALL!
# Wobble...
# Darn! The POKeMON broke free!
# Wild VENONAT is angry!
# ------------------------
# BALLx29 (1)     BAIT (2)
# THROW ROCK (3)  RUN (4)
# ------------------------
# Select 1, 2, 3 or 4: 
> 1
# THEW used SAFARI BALL!
# Wobble... Wobble... Wobble...
# All right!
# VENONAT was caught!
# Do you want to give a nickname to VENONAT?
# ------------------------
# YES (1) or NO (2)
# ------------------------
# Select 1 or 2:
> 1
# Nickname: 
> Tajiri
# Tajiri was transferred to BILL's PC!
> x$pause()
# 497/500
# BALLx28
# Transferred to BILL's PC: 1
> x$bills_pc
#   nickname species level
# 1   Tajiri VENONAT    22

Graphics

Here’s a screenshot of the game in action using the gamelad RStudio theme and the VT323 font.

Details

The Safari Zone

The Safari Zone is an enclosed area separate from the rest of the game. Game mechanics are different here: you’re allowed 500 steps and 30 balls to capture Pokémon. Also, wild encounters don’t result in a ‘battle’; instead you can ‘bait’ or ‘throw a rock’ to influence the catch rate of the target. I chose to simulate this area due to its relative simplicity compared to other areas of the game, which use a more complex battle mechanic.

Technicals

The fields in the SafariZone class are ‘overworld’ counters, basically: the number of steps and balls remaining, and the number and identity of captures you’ve made.

Methods are:

• $new() to initialise the class and start the game
• $step(), which moves your ‘player’ and may result in an encounter
• $pause() (a copy of the $print() method) to simulate the pause screen from the game, showing the current number of steps and balls remaining

The $step() method does the hard work. It contains code that:

• decides whether you encountered a target, based on the encounter rate of the Safari Zone (~12%)
• selects a wild Pokémon based on the relative encounter-rate slots for the Safari Zone Center Area particular to Pokémon Blue (e.g. 20% for a level 22 Nidoran Female through to 1% for a level 23 Chansey; see safar6::pokemon for details)
• generates individual variation in the selected Pokémon’s speed and HP (IV values), which influence catchability
• prompts you interactively for an action: throw ball, bait, throw rock, run
• adjusts the ‘angry’ and ‘eating’ values of the target and modifies catch rate and run probability as a result (a rock doubles the catch rate and the flee chance; bait halves the catch rate, but makes it four times less likely to run)
• calculates whether the Pokémon will be caught or will run away
• terminates the game if steps or balls are depleted

Omissions

To keep things (much!) simpler than the original, this implementation doesn’t include a number of features from the original game. Some missing elements are:

• visuals (everything is printed in the console)
• movement around a map (all steps are treated as though you’re moving through tall grass)
• all areas of the Safari Zone (only the Center area is used here)
• finding items (they have no use in this context)
• fishing and use of different rod types
• species catch and encounter rates from the other Gen 1 versions (e.g. Scyther is in Red rather than Pinsir; and Yellow has some catch-rate changes)

Sources

Information about game mechanics and values are relatively tricky to come by. I used the following resources:

• Bulbapedia for Pokémon stats and game mechanics
• The Cave of Dragonflies for game mechanics
• the Pokémon Slots website for encounter rates
• the pret/pokered GitHub repo for a disassembly of the games

I also referred to a post I wrote about using {R6} to simulate an Automatic Bell Dispenser from Nintendo’s Animal Crossing: New Horizons (2020).

Code of Conduct

Please note that the {safar6} project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.

Disclaimer

I do not condone throwing rocks at any creature, let alone catching and imprisoning them.

safar6's Issues

Add Easter egg

A mystery guest.

Print text character by character

Rather than have the text appear all at once, which is a bit overwhelming and not true to the original.

Reference Rylan Fowers's YouTube video 'Python Pokemon - Python Class Tutorial for Beginners'.

User should input their name

A readline() call and then all instances of 'BLUE' to be replaced with name.

Add tests

Is there a special way to test R6-class?

Add {lintr} GitHub Action

usethis::use_github_action("lint")

Create quickstep?

Tedious to use $step() repeatedly. Method to keep stepping until an encounter. Add argument quick = TRUE?

Add running list of captures

We've got a count, how about a list?

Nickname your captures

Address lint issues

lintr::lint_package()

Use DVs

HP and speed required.

• Pokemon Tools and Calculators for expected ranges
• Bulbapedia for formulae
• stat mechanics (The Cave of Dragonflies).

Add wobble logic

As per step 7 of capture mechanics (The Cave of Dragonflies).

Polish cat_tw()

Originally wrote it quickly and it does the job. Better:

#' Concatenate and Print with Progressive Reveal
#'
#' Input text-strings and output one character at a time with a delay between.
#' Aims to mimic the Pokemon Blue progressive text reveal; a typewriter-style
#' output.
#'
#' @param ... R objects, intended for strings.
#' @param sleep Numeric. System delay in seconds.
#'
#' @return Output to console.
#'
#' @examples \dontrun{ cat_progressive("hello", "world", sleep = 0.1) }
cat_progress <- function(..., sleep = 0.02) {

  x_paste <- paste(...)

  x_chars <- strsplit(x_paste, "")[[1]]

  for (char in x_chars) {
    cat(char)
    Sys.sleep(sleep)
  }

}

Prompted by chat with Matt Kerlogue.

Add sound effects with sonify()

Bug: 'ran away' code runs when it shouldn't

Problem in the ifelse when a ball is used.

BLUE used SAFARI BALL!
Wobble... Wobble... Wobble...
All right!
EXEGGCUTE was caught!
EXEGGCUTE was transferred to BILL's PC!
Wild EXEGGCUTE ran away!

Bug: end screen doesn't appear when step count gets to zero

> sz$step()
1/500
> sz$step()
0/500
> sz$step()
> sz$step()

Add end screen to summarise results

Include list of captures as per #3

Add encounter code to $step()

Local code to be added in dev-step branch.

General refactor

Make it easier to read and debug.

Add defensive programming

Particularly readlines() inputs. Force 1:4 for user action in an encounter, for example.

Check all calculations and values

As per:

• catch rate/capture method (Bulbapedia)
• angry/eating counters and encounters (Bulbapedia)
• base stats (Bulbapedia
• Safari Zone mechanics (The Cave of Dragonflies)
• Gen 1 capture mechanics (The Cave of Dragonflies)
• Stat mechanics (The Cave of Dragonflies)
• Safari Zone slots from disassembly (pret/pokered)
• Slot encounter rates (PokemonSlots)
• etc

How to effectively terminate the class to end the game?

Currently it just sets steps and balls to zero so the end screen is printed with each attempt at $step().