fix nested viewport hover issue

Author: brachy84

src/main/java/com/cleanroommc/modularui/api/layout/IViewport.java

@@ -9,7 +9,7 @@
 /**
  * A gui element which can transform its children f.e. a scrollable list.
  */
-public interface IViewport {
+public interface IViewport extends IWidget {
 
     /**
      * Apply shifts of this viewport.
@@ -26,7 +26,11 @@ default void transformChildren(IViewportStack stack) {}
      * @param x       x position
      * @param y       y position
      */
-    void getWidgetsAt(IViewportStack stack, HoveredWidgetList widgets, int x, int y);
+    default void getWidgetsAt(IViewportStack stack, HoveredWidgetList widgets, int x, int y) {
+        if (hasChildren()) {
+            getChildrenAt(this, stack, widgets, x, y);
+        }
+    }
 
     /**
      * Gathers all children at a position. Transformations from this viewport are not applied.
@@ -37,7 +41,11 @@ default void transformChildren(IViewportStack stack) {}
      * @param x       x position
      * @param y       y position
      */
-    default void getSelfAt(IViewportStack stack, HoveredWidgetList widgets, int x, int y) {}
+    default void getSelfAt(IViewportStack stack, HoveredWidgetList widgets, int x, int y) {
+        if (isInside(stack, x, y)) {
+            widgets.add(this, stack, getAdditionalHoverInfo(stack, x, y));
+        }
+    }
 
     /**
      * Called during drawing twice (before children are drawn). Once with transformation of this viewport and once without
@@ -71,7 +79,7 @@ static void getChildrenAt(IWidget parent, IViewportStack stack, HoveredWidgetLis
                 stack.pushMatrix();
                 child.transform(stack);
                 if (child.isInside(stack, x, y)) {
-                    widgetList.add(child, stack.peek(), child.getAdditionalHoverInfo(stack, x, y));
+                    widgetList.add(child, stack, child.getAdditionalHoverInfo(stack, x, y));
                 }
                 if (child.hasChildren()) {
                     getChildrenAt(child, stack, widgetList, x, y);
@@ -116,6 +124,4 @@ static boolean foreachChild(IViewportStack stack, IWidget parent, Predicate<IWid
         }
         return true;
     }
-
-    IViewport EMPTY = (viewports, widgets, x, y) -> {};
-}
+}

src/main/java/com/cleanroommc/modularui/api/layout/IViewportStack.java

@@ -5,12 +5,14 @@
 import com.cleanroommc.modularui.utils.Vector3f;
 import com.cleanroommc.modularui.widget.sizer.Area;
 
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.Nullable;
 
 /**
  * This handles all viewports in a GUI. Also keeps track of a matrix stack used for rendering and
  * user interaction.
  */
+@ApiStatus.NonExtendable
 public interface IViewportStack {
 
     /**
@@ -206,4 +208,4 @@ default Vector3f unTransform(Vector3f vec) {
      */
     @Nullable
     TransformationMatrix peek();
-}
+}

src/main/java/com/cleanroommc/modularui/api/widget/IDraggable.java

@@ -1,9 +1,7 @@
 package com.cleanroommc.modularui.api.widget;
 
-import com.cleanroommc.modularui.api.layout.IViewport;
 import com.cleanroommc.modularui.api.layout.IViewportStack;
 import com.cleanroommc.modularui.screen.viewport.ModularGuiContext;
-import com.cleanroommc.modularui.utils.HoveredWidgetList;
 import com.cleanroommc.modularui.widget.sizer.Area;
 
 import org.jetbrains.annotations.Nullable;
@@ -14,12 +12,12 @@
  *
  * @see com.cleanroommc.modularui.widget.DraggableWidget
  */
-public interface IDraggable extends IViewport {
+public interface IDraggable {
 
     /**
      * Gets called every frame after everything else is rendered.
      * Is only called when {@link #isMoving()} is true.
-     * Translate to the mouse pos and draw with {@link com.cleanroommc.modularui.widget.WidgetTree#drawTree(IWidget, ModularGuiContext, boolean)}.
+     * Translate to the mouse pos and draw with {@link com.cleanroommc.modularui.widget.WidgetTree#drawTree(IWidget, ModularGuiContext, boolean, boolean)}.
      *
      * @param partialTicks difference from last from
      */
@@ -61,7 +59,4 @@ default boolean canDropHere(int x, int y, @Nullable IGuiElement widget) {
     void setMoving(boolean moving);
 
     void transform(IViewportStack viewportStack);
-
-    @Override
-    default void getWidgetsAt(IViewportStack stack, HoveredWidgetList widgets, int x, int y) {}
 }

src/main/java/com/cleanroommc/modularui/screen/ModularPanel.java

@@ -197,20 +197,6 @@ public void transform(IViewportStack stack) {
         }
     }
 
-    @Override
-    public void getWidgetsAt(IViewportStack stack, HoveredWidgetList widgets, int x, int y) {
-        if (hasChildren()) {
-            IViewport.getChildrenAt(this, stack, widgets, x, y);
-        }
-    }
-
-    @Override
-    public void getSelfAt(IViewportStack stack, HoveredWidgetList widgets, int x, int y) {
-        if (isInside(stack, x, y)) {
-            widgets.add(this, stack.peek(), getAdditionalHoverInfo(stack, x, y));
-        }
-    }
-
     private void findHoveredWidgets() {
         this.hovering.clear();
         this.hovering.trim();

src/main/java/com/cleanroommc/modularui/screen/viewport/GuiViewportStack.java

@@ -23,6 +23,7 @@ public class GuiViewportStack implements IViewportStack {
 
     private static final Vector3f sharedVec = new Vector3f();
 
+    private final ObjectArrayList<TransformationMatrix> matrixPool = new ObjectArrayList<>(256);
     private final ObjectArrayList<TransformationMatrix> viewportStack = new ObjectArrayList<>();
     private final List<Area> viewportAreas = new ArrayList<>();
     private TransformationMatrix top;
@@ -54,17 +55,29 @@ public void pushViewport(IViewport viewport, Area area) {
             }
             this.topViewport.getArea().clamp(child);
         }
-        this.viewportStack.push(new TransformationMatrix(viewport, child, parent));
+        this.viewportStack.push(newMatrix().construct(viewport, child, parent));
         updateViewport(false);
         this.topViewport = this.viewportStack.top();
     }
 
     @Override
     public void pushMatrix() {
-        this.viewportStack.push(new TransformationMatrix(this.top == null ? null : this.top.getMatrix()));
+        this.viewportStack.push(newMatrix().construct(this.top == null ? null : this.top.getMatrix()));
         updateViewport(false);
     }
 
+    private TransformationMatrix newMatrix() {
+        return !this.matrixPool.isEmpty() ? this.matrixPool.pop() : new TransformationMatrix();
+    }
+
+    private void pop() {
+        TransformationMatrix matrix = this.viewportStack.pop();
+        matrix.dispose();
+        if (this.matrixPool.size() < 256) {
+            this.matrixPool.add(matrix);
+        }
+    }
+
     private Area getCurrentViewportArea() {
         while (this.viewportAreas.size() < this.viewportStack.size() + 1) {
             this.viewportAreas.add(new Area());
@@ -75,24 +88,33 @@ private Area getCurrentViewportArea() {
     @Override
     public void popViewport(IViewport viewport) {
         if (this.top == null || !this.top.isViewportMatrix() || this.top.getViewport() != viewport) {
-            String name = this.top == null ? "null" : this.top.getViewport().toString();
-            throw new IllegalStateException("Viewports must be popped in reverse order they were pushed. Tried to pop '" + viewport + "', but last pushed is '" + name + "'.");
+            String name;
+            if (this.top == null) {
+                name = "none";
+            } else {
+                name = this.top.isViewportMatrix() ? asString(this.top.getViewport()) : "not a viewport";
+            }
+            throw new IllegalStateException("Viewports must be popped in reverse order they were pushed. Tried to pop '" + asString(viewport) + "', but last pushed is '" + name + "'.");
         }
-        this.viewportStack.pop();
+        pop();
         updateViewport(true);
     }
 
+    private static String asString(IViewport viewport) {
+        return viewport == null ? "screen viewport" : viewport.toString();
+    }
+
     @Override
     public void popMatrix() {
         if (this.top.isViewportMatrix()) {
             throw new IllegalStateException("Tried to pop viewport matrix, but at the top is a normal matrix.");
         }
-        this.viewportStack.pop();
+        pop();
         updateViewport(false);
     }
 
     public void push(TransformationMatrix transformationMatrix) {
-        this.viewportStack.push(new TransformationMatrix(transformationMatrix, this.top == null ? null : this.top.getMatrix()));
+        this.viewportStack.push(newMatrix().construct(transformationMatrix, this.top == null ? null : this.top.getMatrix()));
         updateViewport(false);
         if (this.top.isViewportMatrix()) {
             this.topViewport = this.top;
@@ -103,8 +125,9 @@ public void pop(TransformationMatrix transformationMatrix) {
         if (this.top.getWrapped() != transformationMatrix) {
             throw new IllegalArgumentException();
         }
-        TransformationMatrix tm = this.viewportStack.pop();
-        updateViewport(tm.isViewportMatrix());
+        boolean isViewport = this.top.isViewportMatrix();
+        pop();
+        updateViewport(isViewport);
     }
 
     @Override
@@ -115,7 +138,7 @@ public int getStackSize() {
     @Override
     public void popUntilIndex(int index) {
         for (int i = this.viewportStack.size() - 1; i > index; i--) {
-            this.viewportStack.pop();
+            pop();
         }
         updateViewport(true);
     }
@@ -124,7 +147,7 @@ public void popUntilIndex(int index) {
     public void popUntilViewport(IViewport viewport) {
         int i = this.viewportStack.size();
         while (--i >= 0 && this.viewportStack.top().getViewport() != viewport) {
-            this.viewportStack.pop();
+            pop();
         }
         updateViewport(true);
     }
@@ -185,16 +208,14 @@ private void checkViewport() {
 
     private void updateViewport(boolean findTopViewport) {
         this.top = this.viewportStack.isEmpty() ? null : this.viewportStack.top();
-        if (!findTopViewport || this.topViewport == null || !this.topViewport.isViewportMatrix()) return;
+        if (!findTopViewport) return;
         // find new top viewport
         this.topViewport = null;
         if (this.viewportStack.isEmpty()) return;
-        ListIterator<TransformationMatrix> it = this.viewportStack.listIterator(this.viewportStack.size() - 1);
-        while (it.hasPrevious()) {
-            TransformationMatrix transformationMatrix1 = it.previous();
-            if (transformationMatrix1.isViewportMatrix()) {
-                this.topViewport = transformationMatrix1;
-                break;
+        for (int i = this.viewportStack.size() - 1; i >= 0; i--) {
+            TransformationMatrix matrix = this.viewportStack.get(i);
+            if (matrix.isViewportMatrix()) {
+                this.topViewport = matrix;
             }
         }
     }
@@ -245,4 +266,4 @@ private static Vector3f vec(float x, float y, float z) {
         sharedVec.set(x, y, z);
         return sharedVec;
     }
-}
+}

src/main/java/com/cleanroommc/modularui/screen/viewport/LocatedElement.java

@@ -25,4 +25,9 @@ public void applyMatrix(GuiContext context) {
     public void unapplyMatrix(GuiContext context) {
         context.pop(this.transformationMatrix);
     }
+
+    @Override
+    public String toString() {
+        return "LocatedElement[" + getElement() + "]";
+    }
 }

src/main/java/com/cleanroommc/modularui/screen/viewport/LocatedWidget.java

@@ -52,4 +52,9 @@ public LocatedWidget(IWidget element, TransformationMatrix transformationMatrix,
     public Object getAdditionalHoverInfo() {
         return additionalHoverInfo;
     }
+
+    @Override
+    public String toString() {
+        return "LocatedWidget[" + getElement() + " | " + additionalHoverInfo + "]";
+    }
 }

src/main/java/com/cleanroommc/modularui/screen/viewport/TransformationMatrix.java

@@ -5,52 +5,91 @@
 import com.cleanroommc.modularui.utils.Vector3f;
 import com.cleanroommc.modularui.widget.sizer.Area;
 
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.Nullable;
 
 /**
  * A single matrix in a matrix stack. Also has some other information.
  */
+@ApiStatus.Internal
 public class TransformationMatrix {
 
     public static final TransformationMatrix EMPTY = new TransformationMatrix(null);
 
-    private final TransformationMatrix wrapped;
-    private final IViewport viewport;
-    private final Area area;
-    private final Matrix4f matrix;
+    private TransformationMatrix wrapped;
+    private IViewport viewport;
+    private Area area;
+    private final Matrix4f matrix = new Matrix4f();
     private final Matrix4f invertedMatrix = new Matrix4f();
+    private boolean inUse = false;
 
-    private final boolean viewportMatrix;
-    private boolean dirty = true;
+    public TransformationMatrix() {}
+
+    public TransformationMatrix(@Nullable Matrix4f parent) {
+        construct(parent);
+    }
 
     public TransformationMatrix(TransformationMatrix parent, @Nullable Matrix4f parentMatrix) {
+        construct(parent, parentMatrix);
+    }
+
+    private boolean viewportMatrix;
+    private boolean dirty = true;
+
+    TransformationMatrix construct(TransformationMatrix parent, @Nullable Matrix4f parentMatrix) {
+        checkInUse();
         this.wrapped = parent;
         this.viewport = parent.viewport;
         this.area = parent.area;
-        this.matrix = parentMatrix == null ? new Matrix4f(parent.getMatrix()) : Matrix4f.mul(parentMatrix, parent.getMatrix(), null);
+        if (parentMatrix == null) {
+            this.matrix.load(parent.getMatrix());
+        } else {
+            Matrix4f.mul(parentMatrix, parent.getMatrix(), this.matrix);
+        }
         this.viewportMatrix = parent.viewportMatrix;
+        return this;
     }
 
-    public TransformationMatrix(@Nullable Matrix4f parent) {
-        this.wrapped = null;
-        this.viewport = null;
-        this.area = null;
-        this.matrix = new Matrix4f();
-        this.viewportMatrix = false;
-        if (parent != null) {
-            this.matrix.load(parent);
-        }
+    TransformationMatrix construct(@Nullable Matrix4f parent) {
+        return construct(null, null, parent, false);
+    }
+
+    TransformationMatrix construct(IViewport viewport, Area area, @Nullable Matrix4f parent) {
+        return construct(viewport, area, parent, true);
     }
 
-    public TransformationMatrix(IViewport viewport, Area area, @Nullable Matrix4f parent) {
+    private TransformationMatrix construct(IViewport viewport, Area area, @Nullable Matrix4f parent, boolean isViewport) {
+        checkInUse();
         this.wrapped = null;
         this.viewport = viewport;
         this.area = area;
-        this.matrix = new Matrix4f();
-        this.viewportMatrix = true;
+        this.viewportMatrix = isViewport;
         if (parent != null) {
             this.matrix.load(parent);
+        } else {
+            this.matrix.setIdentity();
         }
+        return this;
+    }
+
+    void dispose() {
+        this.wrapped = null;
+        this.viewport = null;
+        this.area = null;
+        this.inUse = false;
+        this.viewportMatrix = false;
+    }
+
+    private void checkInUse() {
+        if (this.inUse) {
+            throw new IllegalStateException("Transformation matrix is already in use!");
+        }
+        this.inUse = true;
+        this.dirty = true;
+    }
+
+    public boolean isInUse() {
+        return inUse;
     }
 
     public TransformationMatrix getWrapped() {