Add WIP graphics subsystem

base/src/main/java/de/staropensource/sosengine/base/data/info/EngineInformation.java

@@ -170,6 +170,19 @@ public final class EngineInformation {
      */
     private String dependencySlf4j;
 
+    /**
+     * Provides the version of the dependency {@code LWJGL}.
+     *
+     * @since 1-alpha0
+     *
+     * -- GETTER --
+     * Provides the version of the dependency {@code LWJGL}.
+     *
+     * @return LWJGL dependency version
+     * @since 1-alpha0
+     */
+    private String dependencyLwjgl;
+
     /**
      * Provides the version of the Gradle plugin {@code Shadow}.
      *
@@ -243,6 +256,7 @@ public final class EngineInformation {
         dependencyJansi = parser.getString("dependencyJansi");
         dependencyReflections = parser.getString("dependencyReflections");
         dependencySlf4j = parser.getString("dependencySlf4j");
+        dependencyLwjgl = parser.getString("dependencyLwjgl");
 
         pluginShadow = parser.getString("pluginShadow");
         pluginLombok = parser.getString("pluginLombok");

base/src/main/java/de/staropensource/sosengine/base/data/placeholders/EngineDependencyLwjgl.java

@@ -0,0 +1,53 @@
+/*
+ * STAROPENSOURCE ENGINE SOURCE FILE
+ * Copyright (c) 2024 The StarOpenSource Engine Contributors
+ * Licensed under the GNU Affero General Public License v3
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.staropensource.sosengine.base.data.placeholders;
+
+import de.staropensource.sosengine.base.classes.Placeholder;
+import de.staropensource.sosengine.base.data.info.EngineInformation;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Implements the {@code engine_dependency_lwjgl} placeholder.
+ *
+ * @see Placeholder
+ * @since 1-alpha0
+ */
+@SuppressWarnings({ "unused" })
+public final class EngineDependencyLwjgl implements Placeholder {
+    /**
+     * Constructor.
+     *
+     * @since 1-alpha0
+     */
+    public EngineDependencyLwjgl() {}
+
+    /** {@inheritDoc} */
+    @NotNull
+    public String getName() {
+        return "engine_dependency_lwjgl";
+    }
+
+    /** {@inheritDoc} */
+    @NotNull
+    @Override
+    public String replace(@NotNull String text) {
+        return text.replace("%" + getName() + "%", EngineInformation.getInstance().getDependencyLwjgl());
+    }
+}

base/src/main/java/de/staropensource/sosengine/base/utility/PlaceholderEngine.java

@@ -91,6 +91,7 @@ public final class PlaceholderEngine {
         placeholders.add(new EngineDependencyLombok());
         placeholders.add(new EngineDependencyJetbrainsAnnotations());
         placeholders.add(new EngineDependencyJansi());
+        placeholders.add(new EngineDependencyLwjgl());
         placeholders.add(new EngineDependencyReflections());
         placeholders.add(new EngineDependencySlf4j());
         // engine_plugin_*

gradle.properties

@@ -12,6 +12,8 @@ dependencyJetbrainsAnnotations=24.1.0
 dependencyJansi=2.4.1
 dependencyReflections=0.10.2
 dependencySlf4j=2.0.13
+dependencyLwjgl=3.3.3
+dependencyLwjglNatives=
 
 # Test dependencies
 dependencyJunit=11.0-M2

graphics/build.gradle

@@ -0,0 +1,46 @@
+plugins {
+    id 'java'
+    id 'io.freefair.lombok' version "${pluginLombok}"
+}
+
+dependencies {
+    // -> Runtime <-
+    // Lombok
+    compileOnly 'org.projectlombok:lombok:' + project.dependencyLombok
+    annotationProcessor 'org.projectlombok:lombok:' + project.dependencyLombok
+
+    // JetBrains Annotations
+    compileOnly 'org.jetbrains:annotations:' + project.dependencyJetbrainsAnnotations
+
+    // -> Testing <-
+    // Jetbrains Annotations
+    testCompileOnly 'org.jetbrains:annotations:' + project.dependencyJetbrainsAnnotations
+
+    // JUnit
+    testImplementation platform('org.junit:junit-bom:5.' + project.dependencyJunit)
+    testImplementation 'org.junit.jupiter:junit-jupiter'
+    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
+
+    // jOOR
+    testImplementation 'org.jooq:joor:' + project.dependencyJoor
+
+    // -> Project <-
+    implementation project(":base")
+}
+
+javadoc.options {
+    setMemberLevel(JavadocMemberLevel.PUBLIC)
+    setOverview("src/main/javadoc/overview.html")
+    setLocale("en_US")
+    setJFlags([
+            // Force Javadoc to use English translations
+            "-Duser.language=en_US"
+    ])
+}
+
+test {
+    useJUnitPlatform()
+    testLogging {
+        events "passed", "skipped", "failed"
+    }
+}

graphics/gradle

@@ -0,0 +1 @@
+../gradle

graphics/gradlew

@@ -0,0 +1 @@
+../gradlew

graphics/gradlew.bat

@@ -0,0 +1 @@
+../gradlew.bat

graphics/src/main/java/de/staropensource/sosengine/graphics/GraphicsSubsystem.java

@@ -0,0 +1,227 @@
+/*
+ * STAROPENSOURCE ENGINE SOURCE FILE
+ * Copyright (c) 2024 The StarOpenSource Engine Contributors
+ * Licensed under the GNU Affero General Public License v3
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.staropensource.sosengine.graphics;
+
+import de.staropensource.sosengine.base.annotations.EventListener;
+import de.staropensource.sosengine.base.classes.EventPriority;
+import de.staropensource.sosengine.base.classes.SubsystemMainClass;
+import de.staropensource.sosengine.base.classes.helpers.EventHelper;
+import de.staropensource.sosengine.base.events.internal.InternalEngineShutdownEvent;
+import de.staropensource.sosengine.base.logging.LoggerInstance;
+import de.staropensource.sosengine.base.types.LogIssuer;
+import de.staropensource.sosengine.base.utility.ListFormatter;
+import de.staropensource.sosengine.base.utility.Miscellaneous;
+import de.staropensource.sosengine.graphics.classes.ApiMainClass;
+import de.staropensource.sosengine.graphics.events.GraphicsApiShutdownEvent;
+import de.staropensource.sosengine.graphics.events.GraphicsErrorEvent;
+import lombok.Getter;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.*;
+
+/**
+ * The main object for sos!engine's graphics subsystem.
+ *
+ * @since 1-alpha0
+ */
+@SuppressWarnings({ "unused", "JavadocDeclaration", "JavadocBlankLines" })
+public final class GraphicsSubsystem implements SubsystemMainClass {
+    /**
+     * Instance.
+     *
+     * @since 1-alpha0
+     *
+     * -- GETTER --
+     * Returns the {@link GraphicsSubsystem} instance.
+     *
+     * @return {@link GraphicsSubsystem} instance unless uninitialized
+     * @since 1-alpha0
+     */
+    @Getter
+    private static GraphicsSubsystem instance = null;
+
+    /**
+     * Logger instance.
+     *
+     * @see LoggerInstance
+     * @since 1-alpha0
+     */
+    private final LoggerInstance logger = new LoggerInstance(new LogIssuer(getClass()));
+
+    /**
+     * A list of all registered Graphics APIs.
+     *
+     * @see ApiMainClass
+     * @since 1-alpha0
+     *
+     * -- GETTER --
+     * Returns a list of all registered Graphics APIs.
+     *
+     * @return list of all registered Graphics APIs
+     * @see ApiMainClass
+     * @since 1-alpha0
+     */
+    @NotNull
+    @Getter
+    private final Map<@NotNull String, @NotNull ApiMainClass> registeredApis = new HashMap<>();
+
+    /**
+     * Reference to the active Graphics API main class.
+     *
+     * @see ApiMainClass
+     * @since 1-alpha0
+     *
+     * -- GETTER --
+     * Returns the active Graphics API main class.
+     *
+     * @return active Graphics API main class
+     * @see ApiMainClass
+     * @since 1-alpha0
+     */
+    @Nullable
+    @Getter
+    private ApiMainClass api = null;
+
+    /**
+     * Constructor.
+     *
+     * @since 1-alpha0
+     */
+    public GraphicsSubsystem() {
+        // Check if subsystem has already initialized
+        if (instance == null)
+            instance = this;
+        else {
+            instance.logger.crash("Graphics subsystem tried to initialize twice");
+            return;
+        }
+
+        logger.verb("Initializing subsystem");
+
+        long initTime = Miscellaneous.measureExecutionTime(() -> {
+            // Initialize GraphicsSubsystemConfiguration and load it
+            new GraphicsSubsystemConfiguration();
+            GraphicsSubsystemConfiguration.getInstance().loadConfiguration();
+
+            // Precompute event listeners
+            precomputeEventListeners();
+        });
+
+        logger.info("Initialized subsystem in " + initTime + "ms");
+    }
+
+    /**
+     * Precomputes all graphics subsystem events.
+     *
+     * @since 1-alpha0
+     */
+    public static void precomputeEventListeners() {
+        EventHelper.precomputeEventListeners(GraphicsApiShutdownEvent.class);
+        EventHelper.precomputeEventListeners(GraphicsErrorEvent.class);
+    }
+
+    /**
+     * Shuts the graphics subsystem down.
+     * 
+     * @since 1-alpha0
+     */
+    @EventListener(event = InternalEngineShutdownEvent.class, priority = EventPriority.EXTREMELY_UNIMPORTANT)
+    public static void shutdown() {
+        LoggerInstance logger = instance.logger;
+        logger.verb("Shutting down");
+
+        long shutdownTime = Miscellaneous.measureExecutionTime(() -> new GraphicsApiShutdownEvent().callEvent());
+
+        logger.info("Shut down in " + shutdownTime + "ms");
+    }
+
+    /**
+     * Registers a Graphics API.
+     *
+     * @param mainClass main class of the subsystem
+     * @since 1-alpha0
+     */
+    public void registerGraphicsApi(@NotNull ApiMainClass mainClass) {
+        logger.verb("Registering Graphics API " + mainClass.getApiName() + " (" + mainClass.getClass().getName() + ")");
+
+        Object[] output = Miscellaneous.getMapValue(registeredApis, mainClass).toArray();
+
+        if (output.length == 0 || output[0] == null)
+            registeredApis.put(mainClass.getApiName(), mainClass);
+    }
+
+    /**
+     * Chooses a Graphics API to use automatically based on hardware support.
+     *
+     * @return if a compatible Graphics API has been chosen
+     * @see GraphicsSubsystem#setGraphicsApi(String)
+     * @since 1-alpha0
+     */
+    public boolean setGraphicsApi() {
+        logger.verb("Choosing a compatible Graphics API");
+
+        List<@NotNull String> compatibleApis = new ArrayList<>();
+
+        // Check if registered apis are compatible
+        for (String apiName : registeredApis.keySet())
+            if (registeredApis.get(apiName).isCompatible()) {
+                logger.diag("Choosing a compatible Graphics API: " + apiName + " is compatible");
+                compatibleApis.add(apiName);
+            } else
+                logger.diag("Choosing a compatible Graphics API: " + apiName + " is not compatible");
+
+        logger.diag("Choosing a compatible Graphics API: Compatible are: " + ListFormatter.formatList(compatibleApis));
+
+        // Choose last item in list.
+        if (!compatibleApis.isEmpty()) {
+            logger.verb("Choosing a compatible Graphics API: Chose Graphics API " + compatibleApis.getLast());
+
+            api = registeredApis.get(compatibleApis.getLast());
+            api.initializeApi();
+
+            return true;
+        } else {
+            logger.error("Choosing a compatible Graphics API: No compatible Graphics API found");
+            return false;
+        }
+    }
+
+    /**
+     * Sets the Graphics API to use.
+     *
+     * @param name name of the Graphics API
+     * @see GraphicsSubsystem#setGraphicsApi()
+     * @since 1-alpha0
+     */
+    public void setGraphicsApi(@NotNull String name) {
+        logger.verb("Setting Graphics API " + name);
+
+        if (!registeredApis.containsKey(name))
+            logger.crash("Unable to set Graphics API: Graphics API " + name + " is not registered");
+
+        if (api == null)
+            api = registeredApis.get(name);
+        else
+            logger.crash("Unable to set Graphics API: Graphics API " + api.getApiName() + " already registered");
+
+        api.initializeApi();
+    }
+}

graphics/src/main/java/de/staropensource/sosengine/graphics/GraphicsSubsystemConfiguration.java

@@ -0,0 +1,169 @@
+/*
+ * STAROPENSOURCE ENGINE SOURCE FILE
+ * Copyright (c) 2024 The StarOpenSource Engine Contributors
+ * Licensed under the GNU Affero General Public License v3
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.staropensource.sosengine.graphics;
+
+import de.staropensource.sosengine.base.classes.SubsystemConfiguration;
+import de.staropensource.sosengine.base.logging.Logger;
+import de.staropensource.sosengine.base.types.CodePart;
+import de.staropensource.sosengine.base.types.LogIssuer;
+import de.staropensource.sosengine.base.utility.PropertyParser;
+import lombok.Getter;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Properties;
+
+/**
+ * Provides the engine configuration for all classes in a centralized place.
+ *
+ * @since 1-alpha0
+ */
+@SuppressWarnings({ "unused", "JavadocDeclaration", "JavadocBlankLines" })
+@Getter
+public final class GraphicsSubsystemConfiguration implements SubsystemConfiguration {
+    /**
+     * Instance.
+     *
+     * @since 1-alpha0
+     *
+     * -- GETTER --
+     * Returns the {@link GraphicsSubsystemConfiguration} instance.
+     *
+     * @return {@link GraphicsSubsystemConfiguration} instance
+     * @since 1-alpha0
+     */
+    @Getter
+    private static GraphicsSubsystemConfiguration instance;
+
+    /**
+     * Defines the group every property must start with to be recognized as a subsystem configuration setting.
+     *
+     * @since 1-alpha0
+     *
+     * -- GETTER --
+     * Returns the group that every property must start with to be recognized as a subsystem configuration setting.
+     *
+     * @return property group
+     * @since 1-alpha0
+     */
+    @NotNull
+    @Getter
+    private static final String group = "sosengine.graphics.";
+
+    /**
+     * If enabled, allows for unintentional behaviour and excess logging.<br/>
+     * Unless you want to debug or work on a sensitive part of the graphics subsystem, don't enable this!
+     *
+     * @since 1-alpha0
+     *
+     * -- GETTER --
+     * Gets the value for {@code debug}.
+     *
+     * @return variable value
+     * @see GraphicsSubsystemConfiguration#debug
+     * @since 1-alpha0
+     */
+    private boolean debug;
+
+    /**
+     * If enabled, graphical errors thrown by GLFW will be printed to the log by the subsystem.
+     *
+     * @see de.staropensource.sosengine.graphics.events.GraphicsErrorEvent
+     * @since 1-alpha0
+     *
+     * -- GETTER --
+     * Gets the value for {@code errorGraphicsError}.
+     *
+     * @return variable value
+     * @see GraphicsSubsystemConfiguration#errorGraphicsError
+     * @since 1-alpha0
+     */
+    private boolean errorGraphicsError;
+
+    /**
+     * Constructor.
+     *
+     * @see GraphicsSubsystem
+     * @since 1-alpha0
+     */
+    public GraphicsSubsystemConfiguration() {
+        // Only allow one instance
+        if (instance == null)
+            instance = this;
+        else
+            Logger.crash(new LogIssuer(getClass(), CodePart.ENGINE), "Tried reinitializing " + getClass().getName() + " twice");
+
+        loadDefaultConfiguration();
+    }
+
+    /** {@inheritDoc} */
+    public void loadConfiguration(@NotNull Properties properties) {
+        // Define variables
+        PropertyParser parser = new PropertyParser(properties);
+
+        for (String property : properties.stringPropertyNames()) {
+            // Check if property name starts with group
+            if (!property.startsWith(group)) continue;
+
+            // Skip to important stuff
+            property = property.substring(group.length());
+
+            // Match settings
+            try {
+                switch (property) {
+                    case "debug" -> debug = parser.getBoolean(group + property);
+
+                    case "errorGraphicsError" -> errorGraphicsError = parser.getBoolean(group + property);
+                }
+            } catch (NullPointerException ignored) {}
+        }
+
+        // Disable all debug options if 'debug' is disabled
+        //if (!debug) {}
+    }
+
+    /** {@inheritDoc} */
+    public void loadConfiguration() {
+        loadConfiguration(System.getProperties());
+    }
+
+    /** {@inheritDoc} */
+    public void loadDefaultConfiguration() {
+        debug = false;
+
+        errorGraphicsError = true;
+    }
+
+    /** {@inheritDoc} */
+    @Nullable
+    public Object getSetting(@NotNull String setting) {
+        switch (setting) {
+            case "debug" -> {
+                return debug;
+            }
+            case "errorGraphicsError" -> {
+                return errorGraphicsError;
+            }
+            default -> {
+                return null;
+            }
+        }
+    }
+}

graphics/src/main/java/de/staropensource/sosengine/graphics/classes/ApiMainClass.java

@@ -0,0 +1,87 @@
+/*
+ * STAROPENSOURCE ENGINE SOURCE FILE
+ * Copyright (c) 2024 The StarOpenSource Engine Contributors
+ * Licensed under the GNU Affero General Public License v3
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.staropensource.sosengine.graphics.classes;
+
+import de.staropensource.sosengine.base.Engine;
+import de.staropensource.sosengine.base.annotations.EventListener;
+import de.staropensource.sosengine.base.classes.EventPriority;
+import de.staropensource.sosengine.base.classes.SubsystemMainClass;
+import de.staropensource.sosengine.base.events.internal.InternalEngineShutdownEvent;
+import de.staropensource.sosengine.graphics.events.GraphicsErrorEvent;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * The interface for Graphics API main classes.
+ *
+ * @since 1-alpha0
+ */
+@SuppressWarnings({ "unused" })
+public interface ApiMainClass extends SubsystemMainClass {
+    /**
+     * Initializes the Graphics API.
+     *
+     * @since 1-alpha0
+     */
+    void initializeApi();
+
+    /**
+     * Returns the name of the Graphics API.
+     *
+     * @since 1-alpha0
+     */
+    String getApiName();
+
+    /**
+     * Returns the Graphics API's management class.
+     *
+     * @return a {@link ApiManagementClass}
+     * @see ApiManagementClass
+     * @since 1-alpha0
+     */
+    @NotNull
+    ApiManagementClass getManagement();
+
+    /**
+     * Checks if the Graphics API is compatible with the underlying hardware.
+     *
+     * @return if the Graphics API is compatible
+     * @since 1-alpha0
+     */
+    boolean isCompatible();
+
+    /**
+     * Called when a graphics error occurs.
+     *
+     * @param error graphics error
+     * @since 1-alpha0
+     */
+    @EventListener(event = GraphicsErrorEvent.class)
+    static void onGraphicsError(String error) {}
+
+    /**
+     * Called when the engine shuts down.
+     *
+     * @see Engine#shutdown()
+     * @see Engine#shutdown(int)
+     * @since 1-alpha0
+     */
+    @EventListener(event = InternalEngineShutdownEvent.class, priority = EventPriority.EXTREMELY_UNIMPORTANT)
+    static void shutdownApi() {}
+}

graphics/src/main/java/de/staropensource/sosengine/graphics/classes/ApiManagementClass.java

@@ -0,0 +1,39 @@
+/*
+ * STAROPENSOURCE ENGINE SOURCE FILE
+ * Copyright (c) 2024 The StarOpenSource Engine Contributors
+ * Licensed under the GNU Affero General Public License v3
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.staropensource.sosengine.graphics.classes;
+
+import de.staropensource.sosengine.base.classes.Vec2i;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * The interface for Graphics API management classes.
+ *
+ * @since 1-alpha0
+ */
+@SuppressWarnings({ "unused", "JavadocDeclaration", "JavadocBlankLines" })
+public interface ApiManagementClass {
+    /**
+     * Creates a new {@link Window}.
+     *
+     * @since 1-alpha0
+     */
+    @NotNull
+    Window createWindow(String title, Vec2i size);
+}

graphics/src/main/java/de/staropensource/sosengine/graphics/classes/Window.java

@@ -0,0 +1,58 @@
+/*
+ * STAROPENSOURCE ENGINE SOURCE FILE
+ * Copyright (c) 2024 The StarOpenSource Engine Contributors
+ * Licensed under the GNU Affero General Public License v3
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.staropensource.sosengine.graphics.classes;
+
+import de.staropensource.sosengine.base.classes.Vec2i;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * A window on your screen.
+ *
+ * @since 1-alpha0
+ */
+@SuppressWarnings({ "unused", "JavadocDeclaration", "JavadocBlankLines" })
+public interface Window {
+    /**
+     * A set of all active windows.
+     *
+     * @since 1-alpha0
+     */
+    @NotNull
+    Set<? extends @NotNull Window> windows = new HashSet<>();
+
+    /**
+     * The window name.
+     *
+     * @since 1-alpha0
+     */
+    @NotNull
+    String windowName = "Hello Window!";
+
+    /**
+     * The window size.
+     *
+     * @since 1-alpha0
+     */
+    @NotNull
+    Vec2i windowSize = new Vec2i(0, 0);
+}

graphics/src/main/java/de/staropensource/sosengine/graphics/events/GraphicsApiShutdownEvent.java

@@ -0,0 +1,43 @@
+/*
+ * STAROPENSOURCE ENGINE SOURCE FILE
+ * Copyright (c) 2024 The StarOpenSource Engine Contributors
+ * Licensed under the GNU Affero General Public License v3
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.staropensource.sosengine.graphics.events;
+
+import de.staropensource.sosengine.base.classes.Event;
+import de.staropensource.sosengine.base.classes.helpers.EventHelper;
+
+/**
+ * Called when the Graphics API shuts down.
+ *
+ * @since 1-alpha0
+ */
+@SuppressWarnings({ "unused" })
+public class GraphicsApiShutdownEvent implements Event {
+    /**
+     * Constructor.
+     */
+    public GraphicsApiShutdownEvent() {}
+
+
+    /** {@inheritDoc} */
+    @Override
+    public void callEvent() {
+        EventHelper.invokeAnnotatedMethods(getClass());
+    }
+}

graphics/src/main/java/de/staropensource/sosengine/graphics/events/GraphicsErrorEvent.java

@@ -0,0 +1,49 @@
+package de.staropensource.sosengine.graphics.events;
+
+import de.staropensource.sosengine.base.classes.Event;
+import de.staropensource.sosengine.base.events.LogEvent;
+import de.staropensource.sosengine.base.types.LogIssuer;
+import de.staropensource.sosengine.base.types.LogLevel;
+import de.staropensource.sosengine.base.classes.helpers.EventHelper;
+import org.jetbrains.annotations.NotNull;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+/**
+ * Called when a graphics error occurs.
+ *
+ * @since 1-alpha0
+ */
+@SuppressWarnings({ "unused" })
+public class GraphicsErrorEvent implements Event {
+    /**
+     * Constructor.
+     */
+    public GraphicsErrorEvent() {}
+
+    /**
+     * {@inheritDoc}
+     * @deprecated use the {@code callEvent} method with arguments
+     * @see LogEvent#callEvent(LogLevel, LogIssuer, String)
+     */
+    @Deprecated
+    @Override
+    public void callEvent() {}
+
+    /**
+     * Calls the event and notifies all annotated methods.
+     *
+     * @param error graphics error
+     * @since 1-alpha0
+     */
+    public void callEvent(@NotNull String error) {
+        EventHelper.logCall(getClass());
+
+        for (Method method : EventHelper.getAnnotatedMethods(getClass())) {
+            try {
+                method.invoke(null, error);
+            } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException | NullPointerException | ExceptionInInitializerError ignored) {}
+        }
+    }
+}

graphics/src/main/java/de/staropensource/sosengine/graphics/package-info.java

@@ -0,0 +1,23 @@
+/*
+    STAROPENSOURCE ENGINE SOURCE FILE
+    Copyright (c) 2024 The StarOpenSource Engine Contributors
+    Licensed under the GNU Affero General Public License v3
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as
+    published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Contains the code required for drawing things to a screen.
+ */
+package de.staropensource.sosengine.graphics;

settings.gradle

@@ -2,4 +2,5 @@ rootProject.name = 'sosengine'
 
 include 'base'
 include 'slf4j-compat'
+include 'graphics'
 include 'testapp'

testapp/build.gradle

@@ -17,6 +17,7 @@ dependencies {
     // -> Project <-
     implementation project(":base")
     implementation project(":slf4j-compat")
+    implementation project(":graphics")
 }
 
 javadoc.options {

testapp/src/main/java/de/staropensource/sosengine/testapp/Main.java

@@ -20,10 +20,15 @@
 package de.staropensource.sosengine.testapp;
 
 import de.staropensource.sosengine.base.Engine;
+import de.staropensource.sosengine.base.classes.Vec2i;
 import de.staropensource.sosengine.base.logging.LoggerInstance;
 import de.staropensource.sosengine.base.types.LogIssuer;
+import de.staropensource.sosengine.graphics.GraphicsSubsystem;
+import de.staropensource.sosengine.graphics.classes.ApiMainClass;
+import de.staropensource.sosengine.graphics.classes.ApiManagementClass;
 import de.staropensource.sosengine.slf4j_compat.Slf4jCompatibilitySubsystem;
 import lombok.Getter;
+import lombok.SneakyThrows;
 
 /**
  * The initialization class for sos!engine's development application.
@@ -85,6 +90,7 @@ public class Main {
      * @see Main#main(String[])
      * @param args program's command line arguments
      */
+    @SneakyThrows
     public void run(String[] args) {
         // Initialize sos!engine
         engine = new Engine();
@@ -94,6 +100,19 @@ public class Main {
 
         // Initialize subsystems
         new Slf4jCompatibilitySubsystem();
+        new GraphicsSubsystem();
+
+        // Choose Graphics API to use
+        if (!GraphicsSubsystem.getInstance().setGraphicsApi()) {
+            logger.crash("No Graphics API is compatible");
+        }
+
+        // Define 'api' & 'management' variables
+        ApiMainClass api = GraphicsSubsystem.getInstance().getApi();
+        ApiManagementClass management = api.getManagement();
+
+        // Create window
+        management.createWindow("Test", new Vec2i(960, 540));
 
         // Sleep for five seconds
         Thread.sleep(5000);