Fix glitches for SlotWidgets inside ScrollableListWidgets

src/main/java/gregtech/api/gui/IScissored.java

@@ -0,0 +1,8 @@
+package gregtech.api.gui;
+
+import java.awt.Rectangle;
+
+public interface IScissored {
+
+    Rectangle getScissor();
+}

src/main/java/gregtech/api/gui/Widget.java

@@ -102,6 +102,9 @@ private void recomputePosition() {
         onPositionUpdate();
     }
 
+    public void applyScissor(final int parentX, final int parentY, final int parentWidth, final int parentHeight) {
+    }
+
     protected void onPositionUpdate() {
     }
 

src/main/java/gregtech/api/gui/impl/ModularUIGui.java

@@ -1,9 +1,11 @@
 package gregtech.api.gui.impl;
 
 import gregtech.api.gui.IRenderContext;
+import gregtech.api.gui.IScissored;
 import gregtech.api.gui.ModularUI;
 import gregtech.api.gui.Widget;
 import gregtech.api.net.PacketUIWidgetUpdate;
+import gregtech.api.util.RenderUtil;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.inventory.GuiContainer;
 import net.minecraft.client.renderer.GlStateManager;
@@ -18,6 +20,7 @@
 import org.lwjgl.input.Keyboard;
 import org.lwjgl.input.Mouse;
 
+import java.awt.Rectangle;
 import java.io.IOException;
 
 public class ModularUIGui extends GuiContainer implements IRenderContext {
@@ -87,13 +90,23 @@ public void drawScreen(int mouseX, int mouseY, float partialTicks) {
 
         for (int i = 0; i < this.inventorySlots.inventorySlots.size(); ++i) {
             Slot slot = this.inventorySlots.inventorySlots.get(i);
+            Rectangle scissor = null;
+            if (slot instanceof IScissored) {
+                scissor = ((IScissored) slot).getScissor();
+                if (scissor != null) {
+                    RenderUtil.pushScissorFrame(scissor.x, scissor.y, scissor.width, scissor.height);
+                }
+            }
             if (slot.isEnabled()) {
                 this.drawSlotContents(slot);
             }
             if (isPointInRegion(slot.xPos, slot.yPos, 16, 16, mouseX, mouseY) && slot.isEnabled()) {
                 renderSlotOverlay(slot);
                 setHoveredSlot(slot);
             }
+            if (scissor != null) {
+                RenderUtil.popScissorFrame();
+            }
         }
 
         RenderHelper.disableStandardItemLighting();

src/main/java/gregtech/api/gui/widgets/AbstractWidgetGroup.java

@@ -56,6 +56,12 @@ protected void onPositionUpdate() {
         recomputeSize();
     }
 
+    public void applyScissor(final int parentX, final int parentY, final int parentWidth, final int parentHeight) {
+        for (Widget widget : getContainedWidgets(true)) {
+            widget.applyScissor(parentX, parentY, parentWidth, parentHeight);
+        }
+    }
+
     protected boolean recomputeSize() {
         if (isDynamicSized) {
             Size currentSize = getSize();

src/main/java/gregtech/api/gui/widgets/ScrollableListWidget.java

@@ -62,6 +62,8 @@ private void updateElementPositions() {
             widget.setParentPosition(childPosition);
             currentPosY += widget.getSize().getHeight();
             totalListHeight += widget.getSize().getHeight();
+            final Size size = getSize();
+            widget.applyScissor(position.x, position.y, size.width - scrollPaneWidth, size.height);
         }
         this.totalListHeight = totalListHeight;
         this.slotHeight = widgets.isEmpty() ? 0 : totalListHeight / widgets.size();
@@ -105,6 +107,13 @@ public void drawInBackground(int mouseX, int mouseY, IRenderContext context) {
             super.drawInBackground(finalMouseX, finalMouseY, context));
     }
 
+    public boolean isWidgetClickable(final Widget widget) {
+        if (!super.isWidgetClickable(widget)) {
+            return false;
+        }
+        return isBoxInsideScissor(widget.toRectangleBox());
+    }
+
     private boolean isPositionInsideScissor(int mouseX, int mouseY) {
         return isMouseOverElement(mouseX, mouseY) && !isOnScrollPane(mouseX, mouseY);
     }

src/main/java/gregtech/api/gui/widgets/SlotWidget.java

@@ -1,7 +1,12 @@
 package gregtech.api.gui.widgets;
 
+import java.awt.Rectangle;
+
+import javax.annotation.Nonnull;
+
 import gregtech.api.gui.INativeWidget;
 import gregtech.api.gui.IRenderContext;
+import gregtech.api.gui.IScissored;
 import gregtech.api.gui.Widget;
 import gregtech.api.gui.resources.TextureArea;
 import gregtech.api.util.Position;
@@ -15,8 +20,6 @@
 import net.minecraftforge.items.IItemHandlerModifiable;
 import net.minecraftforge.items.SlotItemHandler;
 
-import javax.annotation.Nonnull;
-
 public class SlotWidget extends Widget implements INativeWidget {
 
     protected SlotItemHandler slotReference;
@@ -29,6 +32,8 @@ public class SlotWidget extends Widget implements INativeWidget {
     protected TextureArea[] backgroundTexture;
     protected Runnable changeListener;
 
+    protected Rectangle scissor;
+
     public SlotWidget(IItemHandler itemHandler, int slotIndex, int xPosition, int yPosition, boolean canTakeItems, boolean canPutItems) {
         super(new Position(xPosition, yPosition), new Size(18, 18));
         this.canTakeItems = canTakeItems;
@@ -43,7 +48,7 @@ protected SlotItemHandler createSlot(IItemHandler itemHandler, int index) {
     @Override
     @SideOnly(Side.CLIENT)
     public void drawInBackground(int mouseX, int mouseY, IRenderContext context) {
-        if (isEnabled && backgroundTexture != null) {
+        if (isEnabled() && backgroundTexture != null) {
             Position pos = getPosition();
             Size size = getSize();
             for (TextureArea backgroundTexture : this.backgroundTexture) {
@@ -71,6 +76,11 @@ public void setEnabled(boolean enabled) {
         isEnabled = enabled;
     }
 
+    @Override
+    public void applyScissor(final int parentX, final int parentY, final int parentWidth, final int parentHeight) {
+        this.scissor = new Rectangle(parentX, parentY, parentWidth, parentHeight);
+    }
+
     @Override
     public void detectAndSendChanges() {
     }
@@ -99,20 +109,26 @@ public SlotLocationInfo getSlotLocationInfo() {
     }
 
     public boolean canPutStack(ItemStack stack) {
-        return isEnabled && canPutItems;
+        return isEnabled() && canPutItems;
     }
 
     public boolean canTakeStack(EntityPlayer player) {
-        return isEnabled && canTakeItems;
+        return isEnabled() && canTakeItems;
     }
 
     public boolean isEnabled() {
-        return isEnabled;
+        if (!this.isEnabled) {
+            return false;
+        }
+        if (this.scissor == null) {
+            return true;
+        }
+        return scissor.intersects(toRectangleBox());
     }
 
     @Override
     public boolean canMergeSlot(ItemStack stack) {
-        return isEnabled;
+        return isEnabled();
     }
 
     public void onSlotChanged() {
@@ -129,7 +145,7 @@ public final SlotItemHandler getHandle() {
         return slotReference;
     }
 
-    protected class WidgetSlotDelegate extends SlotItemHandler {
+    protected class WidgetSlotDelegate extends SlotItemHandler implements IScissored {
 
         public WidgetSlotDelegate(IItemHandler itemHandler, int index, int xPosition, int yPosition) {
             super(itemHandler, index, xPosition, yPosition);
@@ -167,6 +183,11 @@ public void onSlotChanged() {
         public boolean isEnabled() {
             return SlotWidget.this.isEnabled();
         }
+
+        @Override
+        public Rectangle getScissor() {
+            return SlotWidget.this.scissor;
+        }
     }
 
 }