implement entity model rendering

(cherry picked from commit a0e5d51290cf521d511f90e23445206a14c4a772)

src/js/net/minecraft/util/Vector3.js

@@ -6,7 +6,6 @@ window.Vector3 = class {
         this.z = z;
     }
 
-
     addVector(x, y, z) {
         return new Vector3(this.x + x, this.y + y, this.z + z);
     }
@@ -69,4 +68,19 @@ window.Vector3 = class {
         }
     }
 
+    /**
+     * Create an interpolated vector from the current vector position to the given one
+     *
+     * @param vector       The end vector
+     * @param partialTicks Interpolation progress
+     * @return Interpolated vector between the two positions
+     */
+    interpolateTo(vector, partialTicks) {
+        let interpolatedX = this.x + (vector.x - this.x) * partialTicks;
+        let interpolatedY = this.y + (vector.y - this.y) * partialTicks;
+        let interpolatedZ = this.z + (vector.z - this.z) * partialTicks;
+
+        return new Vector3(interpolatedX, interpolatedY, interpolatedZ);
+    }
+
 }