Prevent drawing outside of renderer via glScissor

src/main/java/de/johni0702/minecraft/gui/GuiRenderer.java

@@ -34,6 +34,8 @@ public interface GuiRenderer {
 
     ReadableDimension getSize();
 
+    void setDrawingArea(int x, int y, int width, int height);
+
     void bindTexture(ResourceLocation location);
 
     void bindTexture(ITextureObject texture);

src/main/java/de/johni0702/minecraft/gui/MinecraftGuiRenderer.java

@@ -26,11 +26,13 @@ import lombok.NonNull;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.FontRenderer;
 import net.minecraft.client.gui.Gui;
+import net.minecraft.client.gui.ScaledResolution;
 import net.minecraft.client.renderer.GlStateManager;
 import net.minecraft.client.renderer.Tessellator;
 import net.minecraft.client.renderer.WorldRenderer;
 import net.minecraft.client.renderer.texture.ITextureObject;
 import net.minecraft.util.ResourceLocation;
+import org.lwjgl.opengl.GL11;
 import org.lwjgl.util.Color;
 import org.lwjgl.util.*;
 
@@ -42,9 +44,9 @@ public class MinecraftGuiRenderer implements GuiRenderer {
     private final Gui gui = new Gui();
 
     @NonNull
-    private final ReadableDimension size;
+    private final ScaledResolution size;
 
-    public MinecraftGuiRenderer(ReadableDimension size) {
+    public MinecraftGuiRenderer(ScaledResolution size) {
         this.size = size;
     }
 
@@ -55,7 +57,31 @@ public class MinecraftGuiRenderer implements GuiRenderer {
 
     @Override
     public ReadableDimension getSize() {
-        return size;
+        return new ReadableDimension() {
+            @Override
+            public int getWidth() {
+                return size.getScaledWidth();
+            }
+
+            @Override
+            public int getHeight() {
+                return size.getScaledHeight();
+            }
+
+            @Override
+            public void getSize(WritableDimension dest) {
+                dest.setSize(getWidth(), getHeight());
+            }
+        };
+    }
+
+    @Override
+    public void setDrawingArea(int x, int y, int width, int height) {
+        // glScissor origin is bottom left corner whereas otherwise it's top left
+        y = size.getScaledHeight() - y - height;
+
+        int f = size.getScaleFactor();
+        GL11.glScissor(x * f, y * f, width * f, height * f);
     }
 
     @Override

src/main/java/de/johni0702/minecraft/gui/OffsetGuiRenderer.java

@@ -25,10 +25,8 @@ package de.johni0702.minecraft.gui;
 import lombok.NonNull;
 import net.minecraft.client.renderer.texture.ITextureObject;
 import net.minecraft.util.ResourceLocation;
-import org.lwjgl.util.Point;
-import org.lwjgl.util.ReadableColor;
-import org.lwjgl.util.ReadableDimension;
-import org.lwjgl.util.ReadablePoint;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.util.*;
 
 public class OffsetGuiRenderer implements GuiRenderer {
 
@@ -58,6 +56,33 @@ public class OffsetGuiRenderer implements GuiRenderer {
         return size;
     }
 
+    @Override
+    public void setDrawingArea(int x, int y, int width, int height) {
+        int x2 = x + width;
+        int y2 = y + height;
+        // Convert and clamp top and left border
+        x = Math.max(0, x + position.getX());
+        y = Math.max(0, y + position.getY());
+        // Clamp and convert bottom and right border
+        x2 = Math.min(x2, size.getWidth()) + position.getX();
+        y2 = Math.min(y2, size.getHeight()) + position.getY();
+        // Make sure bottom and top / right and left aren't flipped
+        x2 = Math.max(x2, x);
+        y2 = Math.max(y2, y);
+        // Pass to parent
+        renderer.setDrawingArea(x, y, x2 - x, y2 - y);
+    }
+
+    public void startUsing() {
+        GL11.glPushAttrib(GL11.GL_SCISSOR_BIT);
+        GL11.glEnable(GL11.GL_SCISSOR_TEST);
+        setDrawingArea(0, 0, Integer.MAX_VALUE, Integer.MAX_VALUE);
+    }
+
+    public void stopUsing() {
+        GL11.glPopAttrib();
+    }
+
     @Override
     public void bindTexture(ResourceLocation location) {
         renderer.bindTexture(location);

src/main/java/de/johni0702/minecraft/gui/container/AbstractGuiContainer.java

@@ -161,7 +161,9 @@ public abstract class AbstractGuiContainer<T extends AbstractGuiContainer<T>>
             final ReadableDimension eSize = e.getValue().getRight();
             try {
                 OffsetGuiRenderer eRenderer = new OffsetGuiRenderer(renderer, ePosition, eSize);
+                eRenderer.startUsing();
                 e.getKey().draw(eRenderer, eSize, renderInfo.offsetMouse(ePosition.getX(), ePosition.getY()));
+                eRenderer.stopUsing();
             } catch (Exception ex) {
                 CrashReport crashReport = CrashReport.makeCrashReport(ex, "Rendering Gui");
                 renderInfo.addTo(crashReport);

src/main/java/de/johni0702/minecraft/gui/container/AbstractGuiOverlay.java

@@ -199,7 +199,7 @@ public abstract class AbstractGuiOverlay<T extends AbstractGuiOverlay<T>> extend
                     || screenSize.getWidth() != res.getScaledWidth()
                     || screenSize.getHeight() != res.getScaledHeight()) {
                 screenSize = new Dimension(res.getScaledWidth(), res.getScaledHeight());
-                renderer = new MinecraftGuiRenderer(screenSize);
+                renderer = new MinecraftGuiRenderer(res);
             }
         }
     }

src/main/java/de/johni0702/minecraft/gui/container/AbstractGuiScreen.java

@@ -220,7 +220,7 @@ public abstract class AbstractGuiScreen<T extends AbstractGuiScreen<T>> extends
                 Keyboard.enableRepeatEvents(true);
             }
             screenSize = new Dimension(width, height);
-            renderer = new MinecraftGuiRenderer(screenSize);
+            renderer = new MinecraftGuiRenderer(new ScaledResolution(mc, mc.displayWidth, mc.displayHeight));
         }
 
         public T getWrapper() {