make items darker in pause menu

src/js/net/minecraft/client/Minecraft.js

@@ -158,6 +158,9 @@ window.Minecraft = class {
             this.window.exitFocus();
             screen.setup(this, this.window.width, this.window.height);
         }
+
+        // Update items
+        this.itemRenderer.rebuildAllItems();
     }
 
     onTick() {

src/js/net/minecraft/client/render/BlockRenderer.js

@@ -252,7 +252,7 @@ window.BlockRenderer = class {
         }
     }
 
-    renderGuiBlock(group, block, x, y, size) {
+    renderGuiBlock(group, block, x, y, size, brightness) {
         this.tessellator.startDrawing();
 
         let boundingBox = block.getBoundingBox(null, 0, 0, 0);
@@ -269,6 +269,9 @@ window.BlockRenderer = class {
                 break;
         }
 
+        // Change brightness
+        this.tessellator.transformBrightness(brightness);
+
         // Create mesh
         let mesh = this.tessellator.draw(group);
         mesh.geometry.center();

src/js/net/minecraft/client/render/Tessellator.js

@@ -44,6 +44,12 @@ window.Tessellator = class {
         this.colors.push(this.blue);
     }
 
+    transformBrightness(brightness) {
+        for (let i in this.colors) {
+            this.colors[i] *= brightness;
+        }
+    }
+
     draw(group) {
         let geometry = new THREE.BufferGeometry();
         geometry.setAttribute('position', new THREE.BufferAttribute(new Float32Array(this.vertices), 3));

src/js/net/minecraft/client/render/gui/ItemRenderer.js

@@ -53,21 +53,35 @@ window.ItemRenderer = class {
         if (typeof meta === "undefined") {
             let meta = {};
 
+            // To make the items darker
+            let paused = this.minecraft.isPaused();
+
+            // Render item
             let group = new THREE.Group();
-            this.minecraft.worldRenderer.blockRenderer.renderGuiBlock(group, block, x, y, 10);
+            this.minecraft.worldRenderer.blockRenderer.renderGuiBlock(group, block, x, y, 10, paused ? 0.5 : 1);
             this.scene.add(group);
 
+            // Create meta
             meta.group = group;
             meta.typeId = block.getId();
             meta.x = x;
             meta.y = y;
+            meta.dirty = false;
             this.items[renderId] = meta;
         } else {
-            if (meta.typeId !== block.getId() || meta.x !== x || meta.y !== y) {
+            // Check if rendered item has changed
+            if (meta.dirty || meta.typeId !== block.getId() || meta.x !== x || meta.y !== y) {
+                // Rebuild item
                 this.scene.remove(meta.group);
                 delete this.items[renderId];
                 this.renderItemInGui(renderId, block, x, y);
             }
         }
     }
+
+    rebuildAllItems() {
+        for (let i in this.items) {
+            this.items[i].dirty = true;
+        }
+    }
 }