skulls

README

Skulls! A simple Columns-like strategy game developed in Golang with the Ebiten library (for Android)

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• The game was developed as a POC to experience creating a simple game with Go/deploying it to Android
• The Ebiten library for Golang was used to create the game
• go-inovation was used as a guide for the ebitenmobile .aar binding
• All development/debugging was done with the gomobile tool and adb
• Android Studio should be downloaded/installed; the AVD emulators are free and convenient
• I use the AVD emulators that are installable with Android Studio and stored in
  $ANDROID_HOME/emulator/emulator
• It may be helpful to store an alias in your profile to open an emulator via a simple command:
  alias pixel4='$ANDROID_HOME/emulator/emulator -avd "Pixel_4_API_30"'
• Font used for text: RADIOLAND.TTF
• All assets/ (images, audio, and font) were converted to []byte using file2byteslice
• The project is intended to be built with gomobile for development and testing, or with ebitenmobile for production releases using Android Studio

Build .apk for development and testing using gomobile:

  
// 1. Navigate to skulls/ and generate a .apk with gomobile:
gomobile build -target=android github.com/rootVIII/skulls/skullsgomobile



// 2. Install the newly created .apk into an already running Android Emulator:
adb -s <emulator-name> install skullsgomobile.apk

// Note: to list available emulators (including phone connected for debugging):
adb devices -l



// 3. View debug/logging output from the game:
adb logcat
  

Build .aar for Android Studio binding and production release using ebitenmobile:

  
// 1. Navigate to skulls/ and generate the .aar binding:
ebitenmobile bind -target android -javapkg com.<your-username>.skulls -o skulls.aar github.com/rootVIII/skulls/skullsebitenbind



// 2. Create a new Android Studio project (choose Empty Activity) and name it SkullsMobile



// 3. Import the new .aar as a module:
// Select File, New, New Module, Import .jar/.aar Package, select the previously built .aar named skulls.aar
// In app/build.gradle, add this line to the dependencies: compile project(':skulls')
// Example:

dependencies {
    implementation 'androidx.appcompat:appcompat:1.3.0'
    implementation 'com.google.android.material:material:1.3.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
    compile project(':skulls')
}
// Then follow screen prompts to sync the build.gradle change to the project



// 4. Place the following in app/src/main/java/com.<your username>.skullsmobile/MainActivity.java:

package com.<your-username>.skullsmobile;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import go.Seq;
import com.<your-username>.skulls.skullsebitenbind.EbitenView;


public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Seq.setContext(getApplicationContext());
    }

    private EbitenView getEbitenView() {
        return (EbitenView)this.findViewById(R.id.ebitenview);
    }

    @Override
    protected void onPause() {
        super.onPause();
        this.getEbitenView().suspendGame();
    }

    @Override
    protected void onResume() {
        super.onResume();
        this.getEbitenView().resumeGame();
    }
}



// 5. Add a separate error handling class in app/src/main/java/com.<your-username>skullsmobile/EbitenViewWithErrorHandling.java

package com.solsticenet.skullsmobile;

import android.content.Context;
import android.util.AttributeSet;

import com.<your-username>.skulls.skullsebitenbind.EbitenView;


class EbitenViewWithErrorHandling extends EbitenView {
    public EbitenViewWithErrorHandling(Context context) {
        super(context);
    }

    public EbitenViewWithErrorHandling(Context context, AttributeSet attributeSet) {
        super(context, attributeSet);
    }

    @Override
    protected void onErrorOnGameUpdate(Exception e) {
        // You can define your own error handling e.g., using Crashlytics.
        // e.g., Crashlytics.logException(e);
        super.onErrorOnGameUpdate(e);
    }
}



// 6. Add the below into app/src/main/res/AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/background_material_dark"
    android:keepScreenOn="true"
    android:screenOrientation="portrait"
    tools:context="com.<your-username>.skullsmobile.MainActivity">

    <com.<your-username>.skullsmobile.EbitenViewWithErrorHandling
        android:id="@+id/ebitenview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:focusable="true" />
</RelativeLayout>



// 7. The game should now be usable in Android Studio (sign the project with developer keys, UI adjustments in AndroidManifest.xml etc.)
  

This was developed on macOS Big Sur.

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Author: rootVIII 2021

Documentation

Overview

Package skulls A simple strategy game about skulls Copyright (C) 2021 rootVIII

colleyloyejames@gmail.com

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

Index

• Variables
• type Game
  • func Load() (*Game, error)
  • func (g *Game) Draw(screen *ebiten.Image)
  • func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int)
  • func (g *Game) Update() error

Variables

var Clock float64

Clock is the global game clock.

Types

type Game

type Game struct {
	// contains filtered or unexported fields
}

Game controls overall gameplay.

func Load

func Load() (*Game, error)

Load is the entry point to the game.

func (*Game) Draw

func (g *Game) Draw(screen *ebiten.Image)

Draw the screen every frame (typically 1/60[s] for 60Hz display).

func (*Game) Layout

func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int)

Layout takes the outside/window size and returns the (logical) screen size.

func (*Game) Update

func (g *Game) Update() error

Update proceeds the game state every tick (1/60 [s] by default).