Add 3D panoramic skybox feature with 4 different skies.

src/main/java/rs117/hd/HdPlugin.java

@@ -102,6 +102,7 @@
 import rs117.hd.renderer.zone.SceneManager;
 import rs117.hd.renderer.zone.ZoneRenderer;
 import rs117.hd.scene.AreaManager;
+import rs117.hd.scene.CustomSkyboxManager;
 import rs117.hd.scene.EnvironmentManager;
 import rs117.hd.scene.FishingSpotReplacer;
 import rs117.hd.scene.GamevalManager;
@@ -217,6 +218,7 @@ public class HdPlugin extends Plugin {
 	// Manually instantiate singletons and lazily inject them to avoid circular dependencies
 	private static final List<Class<?>> LAZY_SINGLETONS = List.of(
 		AreaManager.class,
+		CustomSkyboxManager.class,
 		EnvironmentManager.class,
 		GamevalManager.class,
 		GroundMaterialManager.class,
@@ -263,6 +265,9 @@ public class HdPlugin extends Plugin {
 	@Inject
 	private EnvironmentManager environmentManager;
 
+	@Inject
+	private CustomSkyboxManager customSkyboxManager;
+
 	@Inject
 	private TextureManager textureManager;
 
@@ -712,6 +717,7 @@ protected void startUp() {
 				modelOverrideManager.startUp();
 				lightManager.startUp();
 				environmentManager.startUp();
+				customSkyboxManager.startUp();
 				fishingSpotReplacer.startUp();
 				gammaCalibrationOverlay.initialize();
 				npcDisplacementCache.initialize();
@@ -781,6 +787,7 @@ protected void shutDown() {
 			modelOverrideManager.shutDown();
 			lightManager.shutDown();
 			environmentManager.shutDown();
+			customSkyboxManager.shutDown();
 			fishingSpotReplacer.shutDown();
 			areaManager.shutDown();
 			gamevalManager.shutDown();

src/main/java/rs117/hd/HdPluginConfig.java

@@ -53,6 +53,7 @@
 import rs117.hd.config.TextureResolution;
 import rs117.hd.config.UIScalingMode;
 import rs117.hd.config.VanillaShadowMode;
+import rs117.hd.config.SkyboxTheme;
 
 import static rs117.hd.HdPlugin.MAX_DISTANCE;
 import static rs117.hd.HdPlugin.MAX_FOG_DEPTH;
@@ -797,12 +798,54 @@ default boolean characterDisplacement() {
 	default boolean pohThemeEnvironments() { return true; }
 
 
+	/*====== Skybox settings ======*/
+
+	@ConfigSection(
+		name = "Skybox",
+		description = "Settings for high-resolution 3D panoramic skybox rendering templates.",
+		position = 4,
+		closedByDefault = true
+	)
+	String skyboxSettings = "skyboxSettings";
+
+	String KEY_SELECTED_SKYBOX_THEME = "selectedSkyboxTheme";
+	@ConfigItem(
+		keyName = KEY_SELECTED_SKYBOX_THEME,
+		name = "Skybox Style",
+		description = "Select the panoramic 3D skybox style.<br>Select 'None' to use default 117 skybox.",
+		position = 0,
+		section = skyboxSettings
+	)
+	default SkyboxTheme selectedSkyboxTheme()
+	{
+		return SkyboxTheme.NONE;
+	}
+	@ConfigItem(keyName = KEY_SELECTED_SKYBOX_THEME, hidden = true, name = "", description = "")
+	void selectedSkyboxTheme(SkyboxTheme theme);
+
+	String KEY_CUSTOM_SKYBOX_NAME = "customSkyboxName";
+	@ConfigItem(
+		keyName = KEY_CUSTOM_SKYBOX_NAME,
+		name = "Custom Skybox Name",
+		description = "When 'Skybox Style' is set to Custom, the skybox to use.<br>" +
+			"Drop an image into .runelite/117hd/custom-skyboxes/ and enter its filename here<br>" +
+			"(with or without its file extension), or add a manifest.json there for<br>" +
+			"cubemaps/multiple skies.<br>" +
+			"In-game commands: ::117hd skybox list, ::117hd skybox cycle, ::117hd skybox open.",
+		position = 1,
+		section = skyboxSettings
+	)
+	default String customSkyboxName() { return ""; }
+	@ConfigItem(keyName = KEY_CUSTOM_SKYBOX_NAME, hidden = true, name = "", description = "")
+	void customSkyboxName(String name);
+
+
 	/*====== Miscellaneous settings ======*/
 
 	@ConfigSection(
 		name = "Miscellaneous",
 		description = "Miscellaneous settings",
-		position = 4,
+		position = 5,
 		closedByDefault = true
 	)
 	String miscellaneousSettings = "miscellaneousSettings";
@@ -956,7 +999,7 @@ default boolean windowsHdrCorrection() {
 	@ConfigSection(
 		name = "Legacy",
 		description = "Legacy options. If you dislike a change, you might find an option to change it back here.",
-		position = 5,
+		position = 6,
 		closedByDefault = true
 	)
 	String legacySettings = "legacySettings";
@@ -1109,7 +1152,7 @@ default boolean legacyTzHaarReskin() {
 	@ConfigSection(
 		name = "Experimental",
 		description = "Experimental features - if you're experiencing issues you should consider disabling these.",
-		position = 6,
+		position = 7,
 		closedByDefault = true
 	)
 	String experimentalSettings = "experimentalSettings";

src/main/java/rs117/hd/config/SkyboxTheme.java

@@ -0,0 +1,18 @@
+package rs117.hd.config;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public enum SkyboxTheme {
+	NONE("None"),
+	CUSTOM("Custom");
+
+	private final String name;
+
+	@Override
+	public String toString() {
+		return name;
+	}
+}

src/main/java/rs117/hd/opengl/shader/SkyboxShaderProgram.java

@@ -0,0 +1,45 @@
+package rs117.hd.opengl.shader;
+
+import java.io.IOException;
+
+import static org.lwjgl.opengl.GL33C.*;
+
+public abstract class SkyboxShaderProgram extends ShaderProgram {
+	protected final UniformTexture uniSkyboxTexture = addUniformTexture("skyboxTexture");
+	protected final UniformTexture uniSkyboxCubemap = addUniformTexture("skyboxCubemap");
+
+	protected boolean isCubemap;
+
+	SkyboxShaderProgram() {
+		super(t -> t
+			.add(GL_VERTEX_SHADER, "skybox_vert.glsl")
+			.add(GL_FRAGMENT_SHADER, "skybox_frag.glsl"));
+	}
+
+	@Override
+	public void compile(ShaderIncludes includes) throws ShaderException, IOException {
+		super.compile(includes.copy().define("IS_CUBEMAP", isCubemap));
+	}
+
+	public void setSkyboxTexture(int textureUnit) {
+		uniSkyboxTexture.set(textureUnit);
+	}
+
+	public void setSkyboxCubemap(int textureUnit) {
+		uniSkyboxCubemap.set(textureUnit);
+	}
+
+	public static class Equirect extends SkyboxShaderProgram {
+		public Equirect() {
+			isCubemap = false;
+			uniSkyboxCubemap.ignoreMissing = true;
+		}
+	}
+
+	public static class Cubemap extends SkyboxShaderProgram {
+		public Cubemap() {
+			isCubemap = true;
+			uniSkyboxTexture.ignoreMissing = true;
+		}
+	}
+}

src/main/java/rs117/hd/renderer/zone/ZoneRenderer.java

@@ -43,19 +43,23 @@
 import rs117.hd.config.ColorFilter;
 import rs117.hd.config.DynamicLights;
 import rs117.hd.config.ShadowMode;
+import rs117.hd.config.SkyboxTheme;
 import rs117.hd.opengl.shader.SceneShaderProgram;
 import rs117.hd.opengl.shader.ShaderException;
 import rs117.hd.opengl.shader.ShaderIncludes;
 import rs117.hd.opengl.shader.ShadowShaderProgram;
+import rs117.hd.opengl.shader.SkyboxShaderProgram;
 import rs117.hd.opengl.uniforms.UBOLights;
 import rs117.hd.opengl.uniforms.UBOWorldViews;
 import rs117.hd.overlays.FrameTimer;
 import rs117.hd.overlays.Timer;
 import rs117.hd.renderer.Renderer;
+import rs117.hd.scene.CustomSkyboxManager;
 import rs117.hd.scene.EnvironmentManager;
 import rs117.hd.scene.LightManager;
 import rs117.hd.scene.ProceduralGenerator;
 import rs117.hd.scene.SceneContext;
+import rs117.hd.scene.TextureManager;
 import rs117.hd.scene.lights.Light;
 import rs117.hd.utils.Camera;
 import rs117.hd.utils.ColorUtils;
@@ -91,6 +95,24 @@ public class ZoneRenderer implements Renderer {
 
 	private static int TEXTURE_UNIT_COUNT = HdPlugin.TEXTURE_UNIT_COUNT;
 	public static final int TEXTURE_UNIT_TEXTURED_FACES = GL_TEXTURE0 + TEXTURE_UNIT_COUNT++;
+	public static final int TEXTURE_UNIT_SKYBOX = GL_TEXTURE0 + TEXTURE_UNIT_COUNT++;
+	public static final int TEXTURE_UNIT_SKYBOX_CUBEMAP = GL_TEXTURE0 + TEXTURE_UNIT_COUNT++;
+	private int customSkyboxTextureId;
+	private int customSkyboxCubemapTextureId;
+	private boolean loadedSkyboxIsCubemap;
+	private String loadedCustomSkyboxName;
+
+	@Inject
+	private CustomSkyboxManager customSkyboxManager;
+
+	@Inject
+	private TextureManager textureManager;
+
+	@Inject
+	private SkyboxShaderProgram.Equirect skyboxEquirectProgram;
+
+	@Inject
+	private SkyboxShaderProgram.Cubemap skyboxCubemapProgram;
 
 	private static int UNIFORM_BLOCK_COUNT = HdPlugin.UNIFORM_BLOCK_COUNT;
 	public static final int UNIFORM_BLOCK_WORLD_VIEWS = UNIFORM_BLOCK_COUNT++;
@@ -233,13 +255,18 @@ public void initializeShaders(ShaderIncludes includes) throws ShaderException, I
 		sceneProgram.compile(includes);
 		fastShadowProgram.compile(includes);
 		detailedShadowProgram.compile(includes);
+		skyboxEquirectProgram.compile(includes);
+		skyboxCubemapProgram.compile(includes);
+		// The actual skybox texture is loaded lazily in scenePass() once the configured theme is known
 	}
 
 	@Override
 	public void destroyShaders() {
 		sceneProgram.destroy();
 		fastShadowProgram.destroy();
 		detailedShadowProgram.destroy();
+		skyboxEquirectProgram.destroy();
+		skyboxCubemapProgram.destroy();
 	}
 
 	private void initializeBuffers() {
@@ -774,6 +801,62 @@ private void scenePass() {
 		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 		frameTimer.end(Timer.CLEAR_SCENE);
 
+		// --- DYNAMIC SKYBOX THEME CONFIGURATION TRACKER ---
+		SkyboxTheme currentTheme = config.selectedSkyboxTheme();
+		boolean hasActiveSkyboxTheme = currentTheme == SkyboxTheme.CUSTOM;
+		String currentCustomSkyboxName = config.customSkyboxName();
+
+		if (hasActiveSkyboxTheme && environmentManager.isOverworld()) {
+			// INTERCEPT: Check if the user changed the custom skybox name mid-game
+			if (!currentCustomSkyboxName.equals(loadedCustomSkyboxName)) {
+				// Free the old texture handles from GPU memory if they exist
+				if (customSkyboxTextureId != 0) {
+					glDeleteTextures(customSkyboxTextureId);
+					customSkyboxTextureId = 0;
+				}
+				if (customSkyboxCubemapTextureId != 0) {
+					glDeleteTextures(customSkyboxCubemapTextureId);
+					customSkyboxCubemapTextureId = 0;
+				}
+				loadedSkyboxIsCubemap = false;
+
+				loadCustomSkybox(currentCustomSkyboxName);
+				loadedCustomSkyboxName = currentCustomSkyboxName;
+			}
+
+			// Only run drawing commands if the selected asset loaded successfully
+			if (customSkyboxTextureId != 0 || customSkyboxCubemapTextureId != 0) {
+				glDisable(GL_DEPTH_TEST);
+				glDepthMask(false);
+
+				// isCubemap is a compile-time #define, so equirect and cubemap skyboxes use
+				// separately-compiled shader variants rather than a per-pixel runtime branch.
+				// The camera ray itself is reconstructed in skybox_frag.glsl from the global
+				// UBO's viewMatrix/projectionMatrix, so no per-frame camera uniforms are needed.
+				if (loadedSkyboxIsCubemap) {
+					skyboxCubemapProgram.use();
+					glActiveTexture(TEXTURE_UNIT_SKYBOX_CUBEMAP);
+					glBindTexture(GL_TEXTURE_CUBE_MAP, customSkyboxCubemapTextureId);
+					skyboxCubemapProgram.setSkyboxCubemap(TEXTURE_UNIT_SKYBOX_CUBEMAP);
+				} else {
+					skyboxEquirectProgram.use();
+					glActiveTexture(TEXTURE_UNIT_SKYBOX);
+					glBindTexture(GL_TEXTURE_2D, customSkyboxTextureId);
+					skyboxEquirectProgram.setSkyboxTexture(TEXTURE_UNIT_SKYBOX);
+				}
+
+				glDrawArrays(GL_TRIANGLES, 0, 3);
+
+				glEnable(GL_DEPTH_TEST);
+				glDepthMask(true);
+				sceneProgram.use();
+			} else {
+				sceneProgram.use();
+			}
+		} else {
+			sceneProgram.use();
+		}
+
 		frameTimer.begin(Timer.RENDER_SCENE);
 
 		renderState.enable.set(GL_BLEND);
@@ -1218,4 +1301,40 @@ public void swapScene(Scene scene) {
 			plugin.stopPlugin();
 		}
 	}
-}
+
+	/**
+	 * Loads the custom skybox entry with the given name from {@link CustomSkyboxManager},
+	 * dispatching to the equirectangular or cubemap upload path depending on the entry's declared type.
+	 * Populates {@link #customSkyboxTextureId}, {@link #customSkyboxCubemapTextureId} and
+	 * {@link #loadedSkyboxIsCubemap}. Leaves both texture ids at 0 if the entry can't be found or loaded.
+	 */
+	private void loadCustomSkybox(String name) {
+		var entry = customSkyboxManager.getEntry(name);
+		if (entry == null) {
+			if (!name.isEmpty())
+				log.warn("Custom skybox not found in manifest: {}", name);
+			return;
+		}
+
+		try {
+			switch (entry.type) {
+				case "cubemap":
+					customSkyboxCubemapTextureId = textureManager.createCubemapTexture(customSkyboxManager.loadCubemapFaceImages(entry));
+					loadedSkyboxIsCubemap = true;
+					break;
+				case "cubemap_cross":
+					customSkyboxCubemapTextureId = textureManager.createCubemapTexture(customSkyboxManager.loadCubemapCrossImage(entry));
+					loadedSkyboxIsCubemap = true;
+					break;
+				case "equirect":
+					customSkyboxTextureId = textureManager.createTexture2D(customSkyboxManager.loadEquirectImage(entry));
+					break;
+				default:
+					log.warn("Unknown custom skybox type '{}' for entry '{}'", entry.type, name);
+			}
+		} catch (Exception ex) {
+			log.warn("Failed to load custom skybox '{}'", name, ex);
+		}
+	}
+
+}

src/main/java/rs117/hd/scene/CustomSkyboxEntry.java

@@ -0,0 +1,8 @@
+package rs117.hd.scene;
+
+public class CustomSkyboxEntry {
+	public String name;
+	public String type; // "equirect" | "cubemap" | "cubemap_cross"
+	public String file; // equirect / cubemap_cross
+	public String[] faces; // cubemap, length 6: +X,-X,+Y,-Y,+Z,-Z
+}