editor: game running badge and stop game button during play-tests, crosshair for play from camera position while shift is held, readable outliner names, plain error dialogs with details and no stuck loading status, inspector hints wrap with the dock

src/main/java/com/eliasmueller/llamamod/editor/tools/environment/Ui.java

@@ -1,6 +1,7 @@
 package com.eliasmueller.llamamod.editor.tools.environment;
 
 import com.eliasmueller.llamamod.editor.ui.Icons;
+import com.eliasmueller.llamamod.editor.ui.Widgets;
 import java.awt.BasicStroke;
 import java.awt.Color;
 import java.awt.Component;
@@ -110,7 +111,7 @@ final class Ui {
         }
 
         Form note(String text) {
-            JLabel l = new JLabel("<html><body style='width:230px'>" + text + "</body></html>");
+            JLabel l = Widgets.wrappingLabel(text);
             l.setForeground(UIManager.getColor("Label.disabledForeground"));
             l.setFont(l.getFont().deriveFont(l.getFont().getSize2D() - 1f));
             return full(l);

src/main/java/com/eliasmueller/llamamod/editor/tools/objects/ObjectsEditorPlugin.java

@@ -290,6 +290,8 @@ public final class ObjectsEditorPlugin implements EditorPlugin {
             look.addActionListener(e -> ctx.run("objects.pilot"));
             b.add(look);
             ParamsSection.compact(b);
+            // same alignment as the note above (BoxLayout aligns mixed alignments on one axis)
+            b.setAlignmentX(0);
             root.add(b);
             return root;
         }

src/main/java/com/eliasmueller/llamamod/editor/tools/objects/ParamsSection.java

@@ -15,6 +15,7 @@ import com.eliasmueller.llamamod.editor.tools.objects.ParamSchema.TypeSchema;
 import com.eliasmueller.llamamod.editor.ui.EditorContext;
 import com.eliasmueller.llamamod.editor.ui.Icons;
 import com.eliasmueller.llamamod.editor.ui.InspectorSection;
+import com.eliasmueller.llamamod.editor.ui.Widgets;
 import java.awt.BorderLayout;
 import java.awt.Color;
 import java.awt.FlowLayout;
@@ -132,6 +133,9 @@ final class ParamsSection implements InspectorSection {
             if (st.type().equals("LevelDoor") || st.type().equals("VillageEndDoor")) {
                 exitRow(st);
             }
+            if (Guards.is(st.type())) {
+                guardRow(st);
+            }
             for (int i = 0; i < Math.max(n, sc != null ? sc.paramCount() : 0); i++) {
                 ParamDef d = sc != null ? sc.param(i) : null;
                 if (d == null) {
@@ -172,7 +176,7 @@ final class ParamsSection implements InspectorSection {
         }
 
         static JLabel note(String html) {
-            JLabel l = new JLabel("<html><body style='width: 230px'>" + html + "</body></html>");
+            JLabel l = Widgets.wrappingLabel(html);
             l.setFont(l.getFont().deriveFont(11.5f));
             l.setForeground(UIManager.getColor("Label.disabledForeground"));
             return l;
@@ -322,6 +326,39 @@ final class ParamsSection implements InspectorSection {
                     + " floor (collision material 16) in its grid cell."));
         }
 
+        private void guardRow(Strat st) {
+            Scene s = ctx.scene();
+            String gone = Guards.removedBecause(s, st);
+            int bit = Guards.eventBit(st);
+            String txt = gone != null
+                    ? "<b>Never appears:</b> the game removes it at level start because " + gone + "."
+                    : bit > 0
+                            ? "Starts inside its box. <b>Hidden</b> until event bit " + bit
+                                    + " is set by another object (0 = active from the start)."
+                            : "Starts inside its box; active from the start.";
+            if (gone == null) {
+                full(note(txt));
+                return;
+            }
+            JPanel w = new JPanel(new BorderLayout(6, 0));
+            w.setOpaque(false);
+            w.add(
+                    new JLabel(
+                            "<html><body style='width: 170px'>" + txt + "</body></html>",
+                            Icons.get("warning", 14),
+                            JLabel.LEFT),
+                    BorderLayout.CENTER);
+            JButton fix = new JButton("Box around it");
+            fix.setFocusable(false);
+            fix.setToolTipText("Replace its waypoints with one 4×4 box around the guard");
+            fix.addActionListener(e -> {
+                ctx.execute(Setups.guardBox(s, st));
+                javax.swing.SwingUtilities.invokeLater(this::refresh);
+            });
+            w.add(fix, BorderLayout.EAST);
+            full(w);
+        }
+
         private void waypointRow(Strat st, TypeSchema sc, TypeStats.Stat stats) {
             Scene s = ctx.scene();
             Role role = Roles.of(st);

src/main/java/com/eliasmueller/llamamod/editor/tools/playtest/PlayHereMarker.java

@@ -0,0 +1,225 @@
+package com.eliasmueller.llamamod.editor.tools.playtest;
+
+import com.eliasmueller.llamamod.editor.render.Legend;
+import com.eliasmueller.llamamod.editor.render.Overlay;
+import com.eliasmueller.llamamod.editor.render.Viewport;
+import com.eliasmueller.llamamod.editor.ui.ActionSpec;
+import com.eliasmueller.llamamod.editor.ui.EditorContext;
+import java.awt.AWTEvent;
+import java.awt.Component;
+import java.awt.Container;
+import java.awt.KeyboardFocusManager;
+import java.awt.Toolkit;
+import java.awt.Window;
+import java.awt.event.AWTEventListener;
+import java.awt.event.KeyEvent;
+import java.awt.event.MouseEvent;
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+import java.util.Locale;
+import javax.swing.AbstractButton;
+import javax.swing.Action;
+import javax.swing.ButtonModel;
+import javax.swing.JFrame;
+import javax.swing.JMenu;
+import javax.swing.SwingUtilities;
+import javax.swing.Timer;
+import javax.swing.text.JTextComponent;
+
+/**
+ * Crosshair in the middle of the viewport while Shift is held (or "Play from camera position" is
+ * hovered in the toolbar/menu): the point where Shift+F5 puts the llama. Green = valid start,
+ * red = no usable floor there (the status bar says why).
+ */
+final class PlayHereMarker {
+    static final String ACTION = "level.playHere";
+    private static final int OK = Legend.withAlpha(Legend.rgb(80, 230, 90), 255);
+    private static final int BAD = Legend.withAlpha(Legend.rgb(240, 70, 60), 255);
+    private static final int SHADOW = Legend.withAlpha(Legend.rgb(0, 0, 0), 170);
+
+    private final EditorContext ctx;
+    private final Timer delay;
+    private final Timer refresh;
+    private boolean shift;
+    private boolean shiftArmed;
+    private boolean hover;
+    private boolean mouseDown;
+    private boolean shown;
+    private String lastStatus;
+
+    private PlayHereMarker(EditorContext ctx) {
+        this.ctx = ctx;
+        // Shift+click / Shift+drag should not flash the crosshair
+        delay = new Timer(300, e -> {
+            shiftArmed = true;
+            update();
+        });
+        delay.setRepeats(false);
+        refresh = new Timer(200, e -> draw());
+    }
+
+    static void install(EditorContext ctx) {
+        JFrame f = ctx.frame();
+        if (f == null || ctx.viewport() == null) {
+            return;
+        }
+        PlayHereMarker m = new PlayHereMarker(ctx);
+        AWTEventListener l = m::event;
+        Toolkit.getDefaultToolkit().addAWTEventListener(l, AWTEvent.KEY_EVENT_MASK | AWTEvent.MOUSE_EVENT_MASK);
+        f.addWindowFocusListener(new WindowAdapter() {
+            @Override
+            public void windowLostFocus(WindowEvent e) {
+                m.shift = false;
+                m.update();
+            }
+        });
+        f.addWindowListener(new WindowAdapter() {
+            @Override
+            public void windowClosed(WindowEvent e) {
+                Toolkit.getDefaultToolkit().removeAWTEventListener(l);
+                m.delay.stop();
+                m.refresh.stop();
+            }
+        });
+        m.hookButtons(f.getJMenuBar());
+        m.hookButtons(f.getContentPane());
+    }
+
+    /** Tracks hovering of the toolbar button and menu item of "Play from camera position". */
+    private void hookButtons(Container c) {
+        if (c == null) {
+            return;
+        }
+        Component[] kids = c instanceof JMenu m ? m.getMenuComponents() : c.getComponents();
+        for (Component k : kids) {
+            if (k instanceof AbstractButton b && !(k instanceof JMenu) && isPlayHere(b.getAction())) {
+                ButtonModel bm = b.getModel();
+                bm.addChangeListener(e -> {
+                    boolean h = bm.isRollover() || bm.isArmed();
+                    if (h != hover) {
+                        hover = h;
+                        update();
+                    }
+                });
+            }
+            if (k instanceof Container cc) {
+                hookButtons(cc);
+            }
+        }
+    }
+
+    private static boolean isPlayHere(Action a) {
+        return a != null && a.getValue("spec") instanceof ActionSpec s && ACTION.equals(s.id());
+    }
+
+    private void event(AWTEvent e) {
+        if (!(e.getSource() instanceof Component c) || window(c) != ctx.frame()) {
+            return;
+        }
+        if (e instanceof KeyEvent k) {
+            if (k.getKeyCode() == KeyEvent.VK_SHIFT) {
+                if (k.getID() == KeyEvent.KEY_PRESSED && !shift && !typing()) {
+                    shift = true;
+                    shiftArmed = false;
+                    delay.restart();
+                } else if (k.getID() == KeyEvent.KEY_RELEASED) {
+                    shift = false;
+                    update();
+                }
+            } else if (k.getID() == KeyEvent.KEY_PRESSED && shift && k.getKeyCode() != KeyEvent.VK_F5) {
+                // Shift+Z, Shift+A, …: a shortcut, not "where would I start"
+                shift = false;
+                update();
+            }
+        } else if (e instanceof MouseEvent m) {
+            if (m.getID() == MouseEvent.MOUSE_PRESSED) {
+                mouseDown = true;
+                update();
+            } else if (m.getID() == MouseEvent.MOUSE_RELEASED) {
+                mouseDown = false;
+                update();
+            }
+        }
+    }
+
+    private static Window window(Component c) {
+        return c instanceof Window w ? w : SwingUtilities.getWindowAncestor(c);
+    }
+
+    private static boolean typing() {
+        return KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner() instanceof JTextComponent;
+    }
+
+    /** Shown while hovered, or while Shift is held (after a short delay, without a mouse button). */
+    boolean wanted() {
+        return ctx.document() != null && (hover || shift && shiftArmed && !mouseDown);
+    }
+
+    private void update() {
+        boolean want = wanted();
+        if (want == shown) {
+            return;
+        }
+        shown = want;
+        if (want) {
+            lastStatus = null;
+            draw();
+            refresh.start();
+        } else {
+            refresh.stop();
+            ctx.viewport().setHudOverlay(null);
+        }
+    }
+
+    private void draw() {
+        Viewport vp = ctx.viewport();
+        if (!shown || ctx.scene() == null) {
+            return;
+        }
+        double[] st = new double[4];
+        String problem = PlaytestEditorPlugin.startProblem(ctx, st);
+        int w = vp.canvas().getWidth(), h = vp.canvas().getHeight();
+        vp.setHudOverlay(crosshair(w / 2f, h / 2f, problem == null ? OK : BAD));
+        String msg = problem == null
+                ? String.format(
+                        Locale.ROOT,
+                        "Shift+F5 starts the llama at the crosshair (%.1f, %.1f, %.1f)",
+                        st[0],
+                        st[1],
+                        st[2])
+                : "Shift+F5: " + problem;
+        if (!msg.equals(lastStatus)) {
+            lastStatus = msg;
+            ctx.status(msg);
+        }
+    }
+
+    /** Four arms with a gap and a centre dot, with a dark outline so it shows on any ground. */
+    static Overlay crosshair(float cx, float cy, int rgba) {
+        Overlay o = new Overlay();
+        float a = 5, b = 17, t = 1.5f;
+        float[][] bars = {
+            {cx - b, cy - t, cx - a, cy + t},
+            {cx + a, cy - t, cx + b, cy + t},
+            {cx - t, cy - b, cx + t, cy - a},
+            {cx - t, cy + a, cx + t, cy + b},
+            {cx - t, cy - t, cx + t, cy + t}
+        };
+        // outline as separate strips: overlapping overlay triangles at equal depth may hide each other
+        for (float[] r : bars) {
+            rect(o, r[0] - 1, r[1] - 1, r[2] + 1, r[1], SHADOW);
+            rect(o, r[0] - 1, r[3], r[2] + 1, r[3] + 1, SHADOW);
+            rect(o, r[0] - 1, r[1], r[0], r[3], SHADOW);
+            rect(o, r[2], r[1], r[2] + 1, r[3], SHADOW);
+        }
+        for (float[] r : bars) {
+            rect(o, r[0], r[1], r[2], r[3], rgba);
+        }
+        return o;
+    }
+
+    private static void rect(Overlay o, float x0, float y0, float x1, float y1, int c) {
+        o.triangle(new double[] {x0, y0, 0}, new double[] {x1, y0, 0}, new double[] {x1, y1, 0}, c);
+        o.triangle(new double[] {x0, y0, 0}, new double[] {x1, y1, 0}, new double[] {x0, y1, 0}, c);
+    }
+}

src/main/java/com/eliasmueller/llamamod/editor/tools/playtest/PlaytestEditorPlugin.java

@@ -98,6 +98,7 @@ public final class PlaytestEditorPlugin implements EditorPlugin {
                         + " chapter or original slot), to play it from LlamaMod or share the mod list"));
         x.toolbarAction("level.playHere", "build");
         x.onOpen(PlaytestRunner::resumeRestore);
+        x.onOpen(PlayHereMarker::install);
     }
 
     private static void toggle(EditorContext c, String pref) {
@@ -114,37 +115,47 @@ public final class PlaytestEditorPlugin implements EditorPlugin {
     }
 
     static void playHere(EditorContext ctx) {
+        double[] start = new double[4];
+        String problem = startProblem(ctx, start);
+        if (problem != null) {
+            info(ctx, problem);
+            return;
+        }
+        PlaytestRunner.play(ctx, start);
+    }
+
+    /**
+     * Why the middle of the view is no valid start, or null: then {@code out} = {x, y, z, yaw} of the
+     * floor point there (game cells).
+     */
+    static String startProblem(EditorContext ctx, double[] out) {
+        if (ctx.scene() == null) {
+            return "No level is open.";
+        }
         double[] start = cameraStart(ctx.viewport());
         if (start == null) {
-            info(
-                    ctx,
-                    "Point the view at the ground where the llama should start (the middle of the viewport"
-                            + " must show level geometry).");
-            return;
+            return "Point the view at the ground where the llama should start (the middle of the viewport"
+                    + " must show level geometry).";
         }
         FloorFinder.Floor floor = FloorFinder.near(ctx.scene(), start[0], start[1], start[2]);
-        if (floor == null || floor.material() == FloorFinder.DEATH) {
-            info(
-                    ctx,
-                    floor == null
-                            ? "There is no collision floor under the middle of the view (decorations such as trees"
-                                    + " and roofs often have none) – the llama would fall through. Point the view at"
-                                    + " walkable ground."
-                            : "The ground in the middle of the view is a death floor (material 30).");
-            return;
+        if (floor == null) {
+            return "There is no collision floor under the middle of the view (decorations such as trees"
+                    + " and roofs often have none) – the llama would fall through. Point the view at"
+                    + " walkable ground.";
+        }
+        if (floor.material() == FloorFinder.DEATH) {
+            return "The ground in the middle of the view is a death floor (material 30).";
         }
         if (!FloorFinder.visible(ctx.scene(), floor, floor.x(), floor.z())) {
-            info(
-                    ctx,
-                    "That spot is outside the visible part of the level: its floor belongs to a tile that the"
-                            + " visibility regions do not draw from there (the game would show an empty"
-                            + " world). Choose a spot on the normal walkable ground.");
-            return;
+            return "That spot is outside the visible part of the level: its floor belongs to a tile that the"
+                    + " visibility regions do not draw from there (the game would show an empty"
+                    + " world). Choose a spot on the normal walkable ground.";
         }
-        start[0] = floor.x();
-        start[1] = floor.y() + 0.05;
-        start[2] = floor.z();
-        PlaytestRunner.play(ctx, start);
+        out[0] = floor.x();
+        out[1] = floor.y() + 0.05;
+        out[2] = floor.z();
+        out[3] = start[3];
+        return null;
     }
 
     /** Ground point in the middle of the view (game cells) + camera heading; null if no geometry there. */

src/main/java/com/eliasmueller/llamamod/editor/tools/playtest/PlaytestRunner.java

@@ -275,6 +275,7 @@ public final class PlaytestRunner {
                                 JOptionPane.INFORMATION_MESSAGE);
                     }
                     if (!noLaunch) {
+                        w.setGameRunning(levelName, () -> stopGame(env));
                         watch(w, env, session, true);
                     }
                 });
@@ -299,6 +300,7 @@ public final class PlaytestRunner {
     private static void watch(EditorWindow w, EditorEnv env, Session s, boolean launching) {
         Thread t = new Thread(
                 () -> {
+                    Thread me = Thread.currentThread();
                     try {
                         GameLauncher gl = new GameLauncher(env.paths(), env.config());
                         long t0 = System.currentTimeMillis();
@@ -311,6 +313,7 @@ public final class PlaytestRunner {
                                 break;
                             }
                         }
+                        SwingUtilities.invokeLater(() -> ended(w, me));
                         restore(env, s);
                         SwingUtilities.invokeLater(() -> {
                             env.modsChanged();
@@ -319,8 +322,11 @@ public final class PlaytestRunner {
                     } catch (InterruptedException e) {
                         Thread.currentThread().interrupt();
                     } catch (IOException | RuntimeException e) {
-                        SwingUtilities.invokeLater(() -> w.status("Could not restore the mod selection after the"
-                                + " play-test (apply it in LlamaMod): " + e.getMessage()));
+                        SwingUtilities.invokeLater(() -> {
+                            ended(w, me);
+                            w.status("Could not restore the mod selection after the"
+                                    + " play-test (apply it in LlamaMod): " + e.getMessage());
+                        });
                     }
                 },
                 "playtest-restore");
@@ -333,6 +339,20 @@ public final class PlaytestRunner {
         t.start();
     }
 
+    /** Clears the "game running" state unless a newer play-test has started meanwhile. */
+    private static void ended(EditorWindow w, Thread me) {
+        if (watcher == me) {
+            w.setGameRunning(null, null);
+        }
+    }
+
+    /** Stop button: quits the game; the watcher then restores the mod selection. */
+    static void stopGame(EditorEnv env) {
+        Thread t = new Thread(() -> new GameLauncher(env.paths(), env.config()).kill(), "playtest-stop");
+        t.setDaemon(true);
+        t.start();
+    }
+
     static void restore(EditorEnv env, Session s) throws IOException {
         Config cfg = env.config();
         synchronized (PlaytestRunner.class) {
@@ -416,6 +436,9 @@ public final class PlaytestRunner {
             }
             return;
         }
+        if (new GameLauncher(env.paths(), env.config()).isRunning()) {
+            w.setGameRunning("the previous play-test", () -> stopGame(env));
+        }
         watch(w, env, s, false);
     }
 

src/main/java/com/eliasmueller/llamamod/editor/ui/EditorContext.java

@@ -131,6 +131,13 @@ public interface EditorContext {
 
     void error(String title, Throwable t);
 
+    /**
+     * Play-test state: {@code what} (e.g. the level name) while a game started from the editor runs,
+     * null once it has ended. The window shows it until then (status bar, the Play button becomes
+     * Stop); {@code stop} quits the game (null = no Stop button).
+     */
+    default void setGameRunning(String what, Runnable stop) {}
+
     /** Shows (and focuses) a panel. */
     void showPanel(String id);
 

src/main/java/com/eliasmueller/llamamod/editor/ui/EditorWindow.java

@@ -120,6 +120,9 @@ public final class EditorWindow extends JFrame implements EditorContext {
     private SwingWorker<Object, Object> task;
     private final Overlay toolOverlay = new Overlay();
     private final Overlay toolTop = new Overlay();
+    private JButton playButton;
+    private String gameRunning;
+    private Runnable gameStop;
 
     public EditorWindow(EditorEnv env) {
         super("LlamaMod Level Editor");
@@ -460,11 +463,8 @@ public final class EditorWindow extends JFrame implements EditorContext {
                 b.setFocusable(false);
                 b.setFont(b.getFont().deriveFont(Font.BOLD));
                 if (id.equals("level.play")) {
-                    b.putClientProperty(
-                            "FlatLaf.style",
-                            "background: #C85A1E; foreground: #FFFFFF; borderColor: #A8441A;"
-                                    + " hoverBackground: #D86A2E; pressedBackground: #A8441A; arc: 10");
-                    b.setIcon(Icons.tinted("play", 16, Color.WHITE));
+                    playButton = b;
+                    stylePlayButton();
                 }
                 b.setMargin(new Insets(4, 10, 4, 12));
                 tb.add(Box.createHorizontalStrut(6));
@@ -474,6 +474,56 @@ public final class EditorWindow extends JFrame implements EditorContext {
         return tb;
     }
 
+    private void stylePlayButton() {
+        JButton b = playButton;
+        if (gameRunning == null) {
+            b.setAction(actions.get("level.play"));
+            b.putClientProperty(
+                    "FlatLaf.style",
+                    "background: #C85A1E; foreground: #FFFFFF; borderColor: #A8441A;"
+                            + " hoverBackground: #D86A2E; pressedBackground: #A8441A; arc: 10");
+            b.setIcon(Icons.tinted("play", 16, Color.WHITE));
+            return;
+        }
+        Runnable stop = gameStop;
+        b.setAction(new AbstractAction("Stop game") {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                status("Quitting the game…");
+                stop.run();
+            }
+        });
+        b.setToolTipText("The play-test of " + gameRunning + " is running – click to quit the game");
+        b.putClientProperty(
+                "FlatLaf.style",
+                "background: #3F7F4A; foreground: #FFFFFF; borderColor: #2F6A3A;"
+                        + " hoverBackground: #4C9358; pressedBackground: #2F6A3A; arc: 10");
+        b.setIcon(Icons.tinted("stop", 16, Color.WHITE));
+    }
+
+    /** Status bar texts for tests: {message, sticky game state or null}. */
+    String[] statusTexts() {
+        return new String[] {status.messageText(), status.gameText()};
+    }
+
+    /** The play-test game started from this window, or null (see {@link #setGameRunning}). */
+    public String gameRunning() {
+        return gameRunning;
+    }
+
+    @Override
+    public void setGameRunning(String what, Runnable stop) {
+        gameRunning = what;
+        gameStop = stop;
+        if (status != null) {
+            status.game(what);
+        }
+        if (playButton != null) {
+            stylePlayButton();
+            playButton.setEnabled(what == null ? actions.get("level.play").isEnabled() : stop != null);
+        }
+    }
+
     private void addSection(JToolBar tb, List<String> ids) {
         if (ids == null) {
             return;
@@ -1203,6 +1253,7 @@ public final class EditorWindow extends JFrame implements EditorContext {
                 } catch (ExecutionException e) {
                     Throwable c = e.getCause();
                     if (!(c instanceof CancellationException)) {
+                        status.message(title + " failed");
                         error(title, c);
                     }
                 }
@@ -1233,16 +1284,7 @@ public final class EditorWindow extends JFrame implements EditorContext {
     @Override
     public void error(String title, Throwable t) {
         t.printStackTrace();
-        String msg = t.getMessage() == null ? t.toString() : t.getMessage();
-        if (msg.length() > 1500) {
-            msg = msg.substring(0, 1500) + " …";
-        }
-        JOptionPane.showMessageDialog(
-                this,
-                "<html><body style='width: 420px'>" + ProjectController.esc(msg).replace("\n", "<br>")
-                        + "</body></html>",
-                title,
-                JOptionPane.ERROR_MESSAGE);
+        ErrorDialog.show(this, title, t);
     }
 
     @Override

src/main/java/com/eliasmueller/llamamod/editor/ui/ErrorDialog.java

@@ -0,0 +1,181 @@
+package com.eliasmueller.llamamod.editor.ui;
+
+import java.awt.BorderLayout;
+import java.awt.Component;
+import java.awt.Dimension;
+import java.awt.FlowLayout;
+import java.awt.Font;
+import java.awt.Window;
+import java.io.FileNotFoundException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.io.UncheckedIOException;
+import java.lang.reflect.InvocationTargetException;
+import java.nio.file.AccessDeniedException;
+import java.nio.file.FileSystemException;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.util.Locale;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.ExecutionException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.zip.ZipException;
+import javax.swing.BorderFactory;
+import javax.swing.JComponent;
+import javax.swing.JLabel;
+import javax.swing.JOptionPane;
+import javax.swing.JPanel;
+import javax.swing.JScrollPane;
+import javax.swing.JTextArea;
+import javax.swing.JToggleButton;
+import javax.swing.SwingUtilities;
+
+/** Error message for users: a plain sentence, the technical text (exception, stack trace) behind "Details". */
+public final class ErrorDialog {
+    /** Client property of the message panel holding the plain text (tests). */
+    public static final String MESSAGE_KEY = "llamamod.errorMessage";
+
+    // "java.lang.ClassCastException", "ClassCastException", "NumberFormatException"
+    private static final Pattern TECHNICAL = Pattern.compile(
+            "(?:\\b[a-z_$][\\w$]*\\.)+[A-Z][\\w$]*(?:Exception|Error)\\b|\\b[A-Z]\\w*(?:Exception|Error)\\b");
+
+    private ErrorDialog() {}
+
+    public static void show(Component parent, String title, Throwable t) {
+        JOptionPane.showMessageDialog(parent, panel(t), title, JOptionPane.ERROR_MESSAGE);
+    }
+
+    static JComponent panel(Throwable t) {
+        String plain = plain(t);
+        JPanel p = new JPanel(new BorderLayout(0, 8));
+        p.putClientProperty(MESSAGE_KEY, plain);
+        JLabel l = new JLabel("<html><body style='width: 380px'>"
+                + ProjectController.esc(plain).replace("\n", "<br>") + "</body></html>");
+        p.add(l, BorderLayout.NORTH);
+        JTextArea ta = new JTextArea(details(t), 12, 60);
+        ta.setEditable(false);
+        ta.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 11));
+        ta.setCaretPosition(0);
+        JScrollPane sp = new JScrollPane(ta);
+        sp.setPreferredSize(new Dimension(560, 200));
+        sp.setVisible(false);
+        JToggleButton more = new JToggleButton("Details", Icons.get("chevron-right", 12));
+        more.setSelectedIcon(Icons.get("chevron-down", 12));
+        more.putClientProperty("JButton.buttonType", "borderless");
+        more.setFocusable(false);
+        more.setToolTipText("Technical details (useful for a bug report)");
+        more.setBorder(BorderFactory.createEmptyBorder(2, 0, 2, 4));
+        more.addActionListener(e -> {
+            sp.setVisible(more.isSelected());
+            Window w = SwingUtilities.getWindowAncestor(p);
+            if (w != null) {
+                w.pack();
+            }
+        });
+        JPanel south = new JPanel(new BorderLayout(0, 4));
+        JPanel toggle = new JPanel(new FlowLayout(FlowLayout.LEFT, 0, 0));
+        toggle.add(more);
+        south.add(toggle, BorderLayout.NORTH);
+        south.add(sp, BorderLayout.CENTER);
+        p.add(south, BorderLayout.CENTER);
+        return p;
+    }
+
+    /** One plain sentence without exception class names. */
+    public static String plain(Throwable t) {
+        t = unwrap(t);
+        if (t instanceof NoSuchFileException f) {
+            return "The file " + name(f.getFile()) + " does not exist.";
+        }
+        if (t instanceof AccessDeniedException f) {
+            return "No permission to access " + name(f.getFile()) + ".";
+        }
+        if (t instanceof FileSystemException f) {
+            return "The file " + name(f.getFile()) + " cannot be accessed"
+                    + (f.getReason() == null ? "." : ": " + sentence(f.getReason()));
+        }
+        if (t instanceof FileNotFoundException f) {
+            String m = f.getMessage() == null ? "" : f.getMessage();
+            int i = m.indexOf(" (");
+            return "The file " + name(i > 0 ? m.substring(0, i) : m) + " cannot be opened"
+                    + (i > 0 ? ": " + sentence(m.substring(i + 2).replaceFirst("\\)$", "")) : ".");
+        }
+        if (t instanceof ZipException) {
+            return "The file is damaged (not a readable zip archive).";
+        }
+        if (t instanceof OutOfMemoryError) {
+            return "Not enough memory for this operation.";
+        }
+        String msg = t.getMessage();
+        Throwable c = t.getCause();
+        // "level.json is damaged: Index 34 out of bounds…": the cause's text is for the details
+        if (msg != null && c instanceof RuntimeException && c.getMessage() != null && msg.endsWith(c.getMessage())) {
+            msg = msg.substring(0, msg.length() - c.getMessage().length());
+        }
+        String m = clean(msg);
+        if (m != null) {
+            return m;
+        }
+        return "Something went wrong (an internal error). The details below can help to report it.";
+    }
+
+    /** The message up to the first exception class name, as a sentence; null if nothing readable is left. */
+    static String clean(String msg) {
+        if (msg == null || msg.isBlank()) {
+            return null;
+        }
+        Matcher m = TECHNICAL.matcher(msg);
+        String s = m.find() ? msg.substring(0, m.start()) : msg;
+        s = s.strip().replaceAll("[\\s:;,(–-]+$", "").strip();
+        if (s.length() < 3) {
+            return null;
+        }
+        if (s.length() > 400) {
+            s = s.substring(0, 400) + " …";
+        }
+        return sentence(s);
+    }
+
+    private static String sentence(String s) {
+        s = s.strip();
+        if (s.isEmpty()) {
+            return s;
+        }
+        s = s.substring(0, 1).toUpperCase(Locale.ROOT) + s.substring(1);
+        return s.matches("(?s).*[.!?…)]$") ? s : s + ".";
+    }
+
+    private static String name(String file) {
+        if (file == null || file.isBlank()) {
+            return "";
+        }
+        try {
+            Path p = Path.of(file).getFileName();
+            return p == null ? file : p.toString();
+        } catch (RuntimeException e) {
+            return file;
+        }
+    }
+
+    private static Throwable unwrap(Throwable t) {
+        while (t.getCause() != null
+                && (t instanceof ExecutionException
+                        || t instanceof CompletionException
+                        || t instanceof InvocationTargetException
+                        || t instanceof UncheckedIOException
+                        || t.getMessage() == null
+                        || t.getMessage().equals(t.getCause().toString()))) {
+            t = t.getCause();
+        }
+        return t;
+    }
+
+    /** Exception chain with stack traces. */
+    static String details(Throwable t) {
+        StringWriter sw = new StringWriter();
+        t.printStackTrace(new PrintWriter(sw));
+        String s = sw.toString();
+        return s.length() > 20_000 ? s.substring(0, 20_000) + "\n…" : s;
+    }
+}

src/main/java/com/eliasmueller/llamamod/editor/ui/Icons.java

@@ -295,6 +295,10 @@ public final class Icons {
             g.setColor(GREEN.darker());
             g.draw(p);
         });
+        register("stop", (g, c) -> {
+            g.setColor(c);
+            g.fill(new RoundRectangle2D.Double(3.5, 3.5, 9, 9, 2.5, 2.5));
+        });
         register("cut", (g, c) -> {
             g.draw(new Ellipse2D.Double(2, 10, 4, 4));
             g.draw(new Ellipse2D.Double(10, 10, 4, 4));

src/main/java/com/eliasmueller/llamamod/editor/ui/StatusBar.java

@@ -4,9 +4,11 @@ import com.eliasmueller.llamamod.editor.model.Node;
 import com.eliasmueller.llamamod.editor.model.Scene;
 import com.eliasmueller.llamamod.editor.render.Camera;
 import java.awt.BorderLayout;
+import java.awt.Color;
 import java.awt.Cursor;
 import java.awt.Dimension;
 import java.awt.FlowLayout;
+import java.awt.Font;
 import java.awt.event.MouseAdapter;
 import java.awt.event.MouseEvent;
 import java.util.Locale;
@@ -24,6 +26,7 @@ import org.joml.Vector3f;
 final class StatusBar extends JPanel {
     private final EditorWindow w;
     private final JLabel message = new JLabel(" ");
+    private final JLabel game = new JLabel();
     private final JLabel hover = label(220);
     private final JLabel coords = label(190);
     private final JLabel cell = label(86);
@@ -44,6 +47,15 @@ final class StatusBar extends JPanel {
                 BorderFactory.createEmptyBorder(3, 10, 3, 8)));
         message.setIcon(Icons.get("info", 14));
         add(message, BorderLayout.CENTER);
+        game.setVisible(false);
+        game.setOpaque(true);
+        game.setBackground(new Color(0x3F, 0x7F, 0x4A));
+        game.setForeground(Color.WHITE);
+        game.setFont(game.getFont().deriveFont(Font.BOLD));
+        game.setIcon(Icons.tinted("play", 13, Color.WHITE));
+        game.setBorder(BorderFactory.createEmptyBorder(1, 6, 1, 8));
+        game.setToolTipText("A play-test game started from the editor is running; the Stop game button quits it");
+        add(game, BorderLayout.WEST);
         JPanel right = new JPanel(new FlowLayout(FlowLayout.RIGHT, 6, 0));
         progress.setPreferredSize(new Dimension(160, 12));
         progress.setVisible(false);
@@ -100,6 +112,22 @@ final class StatusBar extends JPanel {
         clear.restart();
     }
 
+    /** Sticky "game running" state (null = none). */
+    void game(String what) {
+        game.setText(what == null ? "" : "Game running: " + what);
+        game.setVisible(what != null);
+        revalidate();
+        repaint();
+    }
+
+    String gameText() {
+        return game.isVisible() ? game.getText() : null;
+    }
+
+    String messageText() {
+        return message.getText();
+    }
+
     void hover(Node n) {
         hover.setText(n == null ? " " : n.label() + (w.viewport().hoverBackFace() ? " (back side)" : ""));
         hover.setIcon(n == null ? null : NodeIcons.icon(n, 13));

src/main/java/com/eliasmueller/llamamod/editor/ui/Widgets.java

@@ -1,9 +1,19 @@
 package com.eliasmueller.llamamod.editor.ui;
 
+import java.awt.Container;
+import java.awt.Dimension;
+import java.awt.Insets;
+import java.awt.event.ComponentAdapter;
+import java.awt.event.ComponentEvent;
 import javax.swing.JButton;
 import javax.swing.JComponent;
+import javax.swing.JLabel;
 import javax.swing.JList;
+import javax.swing.JViewport;
+import javax.swing.SwingUtilities;
 import javax.swing.UIManager;
+import javax.swing.plaf.basic.BasicHTML;
+import javax.swing.text.View;
 
 /** Small Swing building blocks shared by panels and plugins. */
 public final class Widgets {
@@ -18,6 +28,116 @@ public final class Widgets {
         return b;
     }
 
+    /**
+     * Help text (HTML body content) that wraps at the width of its container, so it uses a wider
+     * dock instead of a fixed pixel width. Font and colour can be set as on any label.
+     */
+    public static JLabel wrappingLabel(String html) {
+        return new WrapLabel("<html>" + html + "</html>");
+    }
+
+    private static final class WrapLabel extends JLabel {
+        private static final int FALLBACK = 220;
+        private int laidOutFor = -1;
+        private String naturalKey;
+        private float naturalWidth;
+        private final ComponentAdapter follow = new ComponentAdapter() {
+            @Override
+            public void componentResized(ComponentEvent e) {
+                if (available() != laidOutFor) {
+                    revalidate();
+                }
+            }
+        };
+
+        private JViewport viewport;
+
+        WrapLabel(String html) {
+            super(html);
+            setAlignmentX(LEFT_ALIGNMENT);
+        }
+
+        /**
+         * Width of the parent's content area, but at most what the enclosing scroll viewport shows
+         * (a parent may be wider than the dock, e.g. next to a long row of buttons).
+         */
+        private int available() {
+            Container p = getParent();
+            if (p == null || p.getWidth() <= 0) {
+                return -1;
+            }
+            Insets in = p.getInsets();
+            int w = p.getWidth() - in.left - in.right;
+            if (viewport != null && viewport.getWidth() > 0) {
+                int v = viewport.getExtentSize().width;
+                for (Container c = p; c != null && c != viewport; c = c.getParent()) {
+                    Insets ci = c.getInsets();
+                    v -= ci.left + ci.right;
+                }
+                w = Math.min(w, v);
+            }
+            return w;
+        }
+
+        @Override
+        public void addNotify() {
+            super.addNotify();
+            getParent().addComponentListener(follow);
+            viewport = (JViewport) SwingUtilities.getAncestorOfClass(JViewport.class, this);
+            if (viewport != null) {
+                viewport.addComponentListener(follow);
+            }
+        }
+
+        @Override
+        public void removeNotify() {
+            getParent().removeComponentListener(follow);
+            if (viewport != null) {
+                viewport.removeComponentListener(follow);
+                viewport = null;
+            }
+            super.removeNotify();
+        }
+
+        @Override
+        public Dimension getPreferredSize() {
+            View v = (View) getClientProperty(BasicHTML.propertyKey);
+            if (v == null || isPreferredSizeSet()) {
+                return super.getPreferredSize();
+            }
+            int avail = available();
+            laidOutFor = avail;
+            int w = avail > 0 ? avail : FALLBACK;
+            Insets in = getInsets();
+            float tw = Math.max(40, w - in.left - in.right);
+            float natural = natural();
+            if (natural <= tw) {
+                // undo an earlier narrower layout (the label paints with the view's last width)
+                v.setSize(natural, 0);
+                return super.getPreferredSize();
+            }
+            v.setSize(tw, 0);
+            int h = (int) Math.ceil(v.getPreferredSpan(View.Y_AXIS));
+            return new Dimension((int) tw + in.left + in.right, h + in.top + in.bottom);
+        }
+
+        /** Unwrapped text width (a laid-out view reports its layout width instead). */
+        private float natural() {
+            String key = getText() + "\u0000" + getFont();
+            if (!key.equals(naturalKey)) {
+                naturalKey = key;
+                naturalWidth = BasicHTML.createHTMLView(this, getText()).getPreferredSpan(View.X_AXIS);
+            }
+            return naturalWidth;
+        }
+
+        @Override
+        public Dimension getMinimumSize() {
+            Dimension d = getPreferredSize();
+            return new Dimension(Math.min(d.width, 40), d.height);
+        }
+    }
+
     /** List cell look for a fresh renderer component: selection colours only when selected. */
     public static <C extends JComponent> C listCell(C c, JList<?> list, boolean selected) {
         c.setOpaque(selected);

src/main/java/com/eliasmueller/llamamod/editor/ui/panels/InspectorPanel.java

@@ -19,6 +19,7 @@ import com.eliasmueller.llamamod.editor.ui.Icons;
 import com.eliasmueller.llamamod.editor.ui.InspectorSection;
 import com.eliasmueller.llamamod.editor.ui.NodeIcons;
 import com.eliasmueller.llamamod.editor.ui.Tool;
+import com.eliasmueller.llamamod.editor.ui.Widgets;
 import com.eliasmueller.llamamod.util.SwingListeners;
 import java.awt.BorderLayout;
 import java.awt.Color;
@@ -218,7 +219,7 @@ public final class InspectorPanel extends JPanel {
         JLabel t = new JLabel(title);
         t.setFont(t.getFont().deriveFont(Font.BOLD, 14f));
         t.setForeground(UIManager.getColor("Label.disabledForeground"));
-        JLabel d = new JLabel("<html><body style='width: 220px'>" + text + "</body></html>");
+        JLabel d = Widgets.wrappingLabel(text);
         d.setForeground(UIManager.getColor("Label.disabledForeground"));
         p.add(t, BorderLayout.NORTH);
         p.add(d, BorderLayout.CENTER);

src/main/java/com/eliasmueller/llamamod/editor/ui/panels/OutlinerPanel.java

@@ -33,6 +33,7 @@ import java.awt.event.MouseEvent;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Enumeration;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.IdentityHashMap;
 import java.util.LinkedHashMap;
@@ -119,6 +120,7 @@ public final class OutlinerPanel extends JPanel {
         tree.setShowsRootHandles(true);
         tree.setRowHeight(22);
         tree.setCellRenderer(new RowRenderer());
+        javax.swing.ToolTipManager.sharedInstance().registerComponent(tree);
         tree.getSelectionModel().setSelectionMode(TreeSelectionModel.DISCONTIGUOUS_TREE_SELECTION);
         tree.putClientProperty("JTree.lineStyle", "None");
         tree.setToggleClickCount(0);
@@ -368,13 +370,13 @@ public final class OutlinerPanel extends JPanel {
                 }
                 TileModel m = e.getKey();
                 DefaultMutableTreeNode g =
-                        group(tiles, "tm:" + m.id(), m.label(), NodeIcons.kind(NodeKind.TILE_MODEL, 16));
+                        group(tiles, "tm:" + m.id(), modelName(m), NodeIcons.kind(NodeKind.TILE_MODEL, 16));
                 for (Tile t : e.getValue()) {
-                    leaf(g, t, "Cell " + t.cellX() + ", " + t.cellZ(), t.id());
+                    leaf(g, t, "Cell " + t.cellX() + ", " + t.cellZ(), height(t));
                 }
             }
             for (Tile t : none) {
-                leaf(tiles, t, t.label(), t.id());
+                leaf(tiles, t, "Cell " + t.cellX() + ", " + t.cellZ(), height(t));
             }
         } else {
             Map<Long, List<Tile>> cells = new TreeMap<>();
@@ -389,7 +391,7 @@ public final class OutlinerPanel extends JPanel {
                 DefaultMutableTreeNode g =
                         group(tiles, "cell:" + cx + "," + cz, "Cell " + cx + ", " + cz, Icons.get("cell", 16));
                 for (Tile t : e.getValue()) {
-                    leaf(g, t, t.model() == null ? "?" : t.model().label(), t.id());
+                    leaf(g, t, t.model() == null ? "?" : modelName(t.model()), height(t));
                 }
             }
         }
@@ -421,8 +423,10 @@ public final class OutlinerPanel extends JPanel {
                 if (t.getValue().size() > 1) {
                     parent = group(cg, "type:" + t.getKey(), t.getKey(), NodeIcons.category(c.getKey(), 14));
                 }
+                int nr = 0;
                 for (Strat st : t.getValue()) {
-                    leaf(parent, st, t.getValue().size() > 1 ? st.id() : st.type(), pos(st.gx(), st.gy(), st.gz()));
+                    String name = t.getValue().size() > 1 ? t.getKey() + " " + ++nr : t.getKey();
+                    leaf(parent, st, name, pos(st.gx(), st.gy(), st.gz()));
                 }
             }
         }
@@ -459,7 +463,9 @@ public final class OutlinerPanel extends JPanel {
                 }
             }
         }
+        int chainNr = 0;
         for (PathNode start : starts) {
+            chainNr++;
             List<PathNode> ch = s.chain(start);
             List<PathNode> m = new ArrayList<>();
             for (PathNode p : ch) {
@@ -477,10 +483,10 @@ public final class OutlinerPanel extends JPanel {
             DefaultMutableTreeNode g = group(
                     chains,
                     "chain:" + start.id(),
-                    "Chain " + start.id() + (user != null ? " – " + user : ""),
+                    "Chain " + chainNr + (user != null ? " – " + user : ""),
                     NodeIcons.kind(NodeKind.PATH_NODE, 16));
             for (PathNode p : m) {
-                leaf(g, p, p.id(), pos(p.gx(), p.gy(), p.gz()));
+                leaf(g, p, "Waypoint " + (ch.indexOf(p) + 1), pos(p.gx(), p.gy(), p.gz()));
             }
         }
     }
@@ -493,20 +499,31 @@ public final class OutlinerPanel extends JPanel {
                 leaf(
                         zones,
                         z,
-                        z.isDefault() ? "Default zone (fog, sky, music)" : z.label(),
+                        z.isDefault()
+                                ? "Default zone (fog, sky, music)"
+                                : "Z" + z.label().substring(1),
                         z.isDefault() ? "" : "cell " + z.cellX() + ", " + z.cellZ());
             }
         }
         DefaultMutableTreeNode lights = group(root, "lights", "Lights", NodeIcons.kind(NodeKind.LIGHT, 16));
+        int lightNr = 0;
         for (Light l : s.lights()) {
+            lightNr++;
             if (match(l, q)) {
-                leaf(lights, l, l.label(), l.type() == Light.DIRECTIONAL ? "directional" : "point");
+                leaf(lights, l, "Light " + lightNr, l.type() == Light.DIRECTIONAL ? "directional" : "point");
             }
         }
         DefaultMutableTreeNode brushes = group(root, "brushes", "Brushes", NodeIcons.kind(NodeKind.BRUSH, 16));
+        Map<String, Integer> sameName = new HashMap<>();
         for (Brush b : s.brushes()) {
+            sameName.merge(brushName(b), 1, Integer::sum);
+        }
+        Map<String, Integer> brushNr = new HashMap<>();
+        for (Brush b : s.brushes()) {
+            String name = brushName(b);
+            int nr = brushNr.merge(name, 1, Integer::sum);
             if (match(b, q)) {
-                leaf(brushes, b, b.name().isEmpty() ? b.brushKind().label() : b.name(), b.id());
+                leaf(brushes, b, sameName.get(name) > 1 ? name + " " + nr : name, brushPlace(b));
             }
         }
         DefaultMutableTreeNode assets = group(root, "assets", "Assets", Icons.get("assets", 16));
@@ -514,7 +531,7 @@ public final class OutlinerPanel extends JPanel {
                 group(assets, "assets:models", "Tile models", NodeIcons.kind(NodeKind.TILE_MODEL, 16));
         for (TileModel m : s.tileModels()) {
             if (match(m, q)) {
-                leaf(models, m, m.label(), m.faceCount() + " faces");
+                leaf(models, m, modelName(m), m.faceCount() + " faces");
             }
         }
         DefaultMutableTreeNode meshes =
@@ -527,11 +544,42 @@ public final class OutlinerPanel extends JPanel {
         DefaultMutableTreeNode pages = group(assets, "assets:pages", "Texture pages", Icons.get("texture", 16));
         for (TexturePage p : s.pages()) {
             if (match(p, q)) {
-                leaf(pages, p, p.label(), p.width() + "×" + p.height());
+                leaf(
+                        pages,
+                        p,
+                        p.label().replace("page " + p.id(), "Page " + number(p.id())),
+                        p.width() + "×" + p.height());
             }
         }
     }
 
+    /** "model:12 (…)" → "Model 12 (…)" for unnamed tile models. */
+    private static String modelName(TileModel m) {
+        return m.label().replace(m.id(), "Model " + number(m.id()));
+    }
+
+    /** The number part of an id ("model:12" → "12", "page:n3" → "n3"). */
+    private static String number(String id) {
+        return id.substring(id.indexOf(':') + 1);
+    }
+
+    private static String brushName(Brush b) {
+        return b.name().isEmpty() ? b.brushKind().label() : b.name();
+    }
+
+    /** Centre of a brush (game cells) for the detail column. */
+    static String brushPlace(Brush b) {
+        double[] bb = b.bounds();
+        if (!Double.isFinite(bb[0]) || !Double.isFinite(bb[3])) {
+            return "";
+        }
+        return pos((bb[0] + bb[3]) / 2, bb[1], (bb[2] + bb[5]) / 2);
+    }
+
+    private static String height(Tile t) {
+        return String.format(Locale.ROOT, "y %.1f", t.y());
+    }
+
     static String pos(double x, double y, double z) {
         return String.format(Locale.ROOT, "%.1f, %.1f, %.1f", x, y, z);
     }
@@ -648,6 +696,7 @@ public final class OutlinerPanel extends JPanel {
             lock.setIcon(Icons.get(allLocked || anyLocked ? "lock" : "unlock", 13));
             text.setText(r.label);
             text.setIcon(r.icon);
+            setToolTipText(r.node == null ? null : r.node.id());
             text.setFont(t.getFont().deriveFont(r.node == null ? Font.BOLD : Font.PLAIN));
             Color fg = sel ? UIManager.getColor("Tree.selectionForeground") : UIManager.getColor("Tree.textForeground");
             text.setForeground(allHidden ? UIManager.getColor("Label.disabledForeground") : fg);