- Target device
- Database format
- Licensing and 3rd party
This is a project for V. She loves Rush Hour puzzles. For her birthday (April 2021), I had a goal to make a Rush Hour player for her Android phone, using my Cakelisp and GameLib tools. I completed this goal successfully on March 26, 2021.
Clone the repository and its dependencies:
git clone https://macoy.me/code/macoy/kitty-gridlock.git git submodule update --init --recursive
See SDL's README-android.md for instructions I followed for setting up Android. You need to download Android Studio. (You could get away with only the SDK and build tools, but you'll probably want the debugger when things don't work out of the box anyways.)
Setup_Android.sh to create the proper files and symlink to SDL.
Build_Android.sh. This will fail if you don't have an Android device connected via USB (and in Developer mode). Once it succeeds, the connected Android device will have Kitty Gridlock installed!
You can also open Android Studio, browsed to the Android directory, and hit Debug, Run, etc.
Android/local.properties and set these variables to the ones you have set up (mine, for reference):
Follow SDL Readme, get NDK from SDK Manager, etc.
Known working version(s)
My local build was tested the following software versions:
|SDK Build-Tools||29.03, 28.03, 26¹|
¹= I'm not actually sure which SDK version is being used, because I didn't explicitly specify one.
²= I had to downgrade from version 22 due to
platforms folder missing. See below section.
SDL_main() not found in
Ensure you have
main()defined with its full signature:
int main(int numArgs, char* args)
Note that SDL defines
main()as a macro to be
SDL_main(), which is a bit confusing, but works okay as long as you have the full signature
platforms folder in NDK
I had to downgrade from version 22 due to
platforms folder missing. To do so:
Open Android Studio
Tools -> SDK Manager
Switch to tab
Show Package Details
Expand the NDK tree and check
21.4.7075529, then click OK
Building from the command line
Follow the SDL README-android.md for using
androidbuild.sh, which is how I got the first version going. For reference, here is the command sequence:
cd Dependencies/gamelib/Dependencies/SDL/build-scripts export ANDROID_HOME=/home/macoy/Android/Sdk export ANDROID_NDK_HOME=/home/macoy/Android/Sdk/ndk/21.4.7075529/ ./androidbuild.sh org.libsdl.testgles ../test/testgles.c cd ../build/org.libsdl.testgles # Note: This will only succeed if you have an Android device plugged in to USB, with Developer mode enabled ./gradlew installDebug
All I had to do for my project was copy some files as the Readme instructs, then edit
SDL/build/org.libsdl.testgles/app/jni/src/Android.mk, to add the files and flags, e.g.:
# Work around "bug" in cakelisp where there are extraneous parens LOCAL_CFLAGS += -Wno-parentheses-equality # Copied straight from cakelisp_cache LOCAL_SRC_FILES := Main.cake.cpp Math.cake.cpp SDL.cake.cpp
Fix Android Studio not knowing how to build/debug project
File -> Sync Project files with Gradle files.
V has a OnePlus 6T Android phone with the following specifications (from here):
|Display Type||Optic AMOLED|
|Display Size||6.41 inches, 100.9 cm2|
|Display Resolution||1080 x 2340 pixels, 19.5:9 ratio (~402 ppi density)|
|CPU Chipset||Qualcomm SDM845 Snapdragon 845 (10 nm)|
|CPU||Octa-core (4x2.8 GHz Kryo 385 Gold & 4x1.7 GHz Kryo 385 Silver)|
The two main specs I need to care about are Android Version and Display Resolution. Additionally, AMOLED hints that pure black is going to look nice.
The database is a simple text file with just a few columns. There is one row for every valid (solvable, minimal) cluster. The columns are: number of moves, board description, and cluster size (number of reachable states).
The board description is a 36-character string representing the state of the unsolved board. It is a 6x6 2D array in row-major order. The characters in the description follow these simple rules:
o empty cell
x wall (fixed obstacle)
A primary piece (red car)
B - Z all other pieces
I used lowercase
oinstead of periods
.for the empty cells in the database so that the entire board description can be selected with a double-click.
An example board:
60 IBBxooIooLDDJAALooJoKEEMFFKooMGGHHHM 2332
The entire Rush Hour database decompressed is >100Mb, which is a waste of space on an Android phone. I do some additional processing to make the puzzles suitable for Kitty Gridlock:
src/Decompression.cakehas a constant
g-num-puzzles-to-readwhich is used to throw out most of the puzzles. It outputs
data/puzzles.txt, which is this subset
src/PuzzleIO.cakereads the puzzles subset in text, then writes it to a binary format
data/puzzles.binwhich makes the puzzles trivial to load at runtime
src/Main.cakecalls functions in
PuzzleIOto load the binary puzzles at runtime
Licensing and 3rd party
Kitty Gridlock is copyright (C) 2021 Macoy Madson. Licensed under
GPL-3.0-or-later. Art made by Macoy and V.
Kitty Gridlock uses the following 3rd-party code:
During build time only:
bunzip by Rob Landley, under LGPL v2
Michael Fogleman's Rush Hour database is used to generate a list of puzzles. The code to generate the database is MIT Licensed, but the database itself is ambiguously licensed as far as I can tell (which I should reach out and get clarification on, but have yet to do so)