From 725cfa804553e8642ff5a0a6b935d59de7d08c95 Mon Sep 17 00:00:00 2001
From: Zach Fox <fox@highfidelity.io>
Date: Mon, 30 Jan 2017 11:52:08 -0800
Subject: [PATCH] Fix it!

---
 .../entity-server-filter-example.js           | 52 ++++++++++++++-----
 1 file changed, 38 insertions(+), 14 deletions(-)

diff --git a/script-archive/entity-server-filter-example.js b/script-archive/entity-server-filter-example.js
index 4d4f7273f1..424e6e9668 100644
--- a/script-archive/entity-server-filter-example.js
+++ b/script-archive/entity-server-filter-example.js
@@ -4,51 +4,75 @@ function filter(p) {
     /* Simple example: if someone specifies name, add an 'x' to it. Note that print is ok to use. */
     if (p.name) {p.name += 'x'; print('fixme name', p. name);}
 
+    
     /* This example clamps y. A better filter would probably zero y component of velocity and acceleration. */
     if (p.position) {p.position.y = Math.min(1, p.position.y); print('fixme p.y', p.position.y);}
 
+    
     /* Can also reject altogether */
     if (p.userData) { return false; }
 	
+    
     /* Reject if modifications made to Model properties */
     if (p.modelURL || p.compoundShapeURL || p.shape || p.shapeType || p.url || p.fps || p.currentFrame || p.running || p.loop || p.firstFrame || p.lastFrame || p.hold || p.textures || p.xTextureURL || p.yTextureURL || p.zTextureURL) { return false; }
 	
+    
 	/* Clamp velocity to maxVelocity units/second. Zeroing each component of acceleration keeps us from slamming.*/
 	var maxVelocity = 5;
+    function sign(val) {
+        if (val > 0) {
+            return 1;
+        } else if (val < 0) {
+            return -1;
+        } else {
+            return 0;
+        }
+    }
+    /* Random near-zero value used as "zero" to prevent two sequential updates from being
+    exactly the same (which would cause them to be ignored) */
+    var nearZero = 0.0001 * Math.random() + 0.001;
     if (p.velocity) {
 		if (Math.abs(p.velocity.x) > maxVelocity) {
-			p.velocity.x = Math.sign(p.velocity.x) * maxVelocity;
-			p.acceleration.x = 0;
+			p.velocity.x = sign(p.velocity.x) * (maxVelocity + nearZero);
+			p.acceleration.x = nearZero;
 		}
 		if (Math.abs(p.velocity.y) > maxVelocity) {
-			p.velocity.y = Math.sign(p.velocity.y) * maxVelocity;
-			p.acceleration.y = 0;
+			p.velocity.y = sign(p.velocity.y) * (maxVelocity + nearZero);
+			p.acceleration.y = nearZero;
 		}
 		if (Math.abs(p.velocity.z) > maxVelocity) {
-			p.velocity.z = Math.sign(p.velocity.z) * maxVelocity;
-			p.acceleration.z = 0;
+			p.velocity.z = sign(p.velocity.z) * (maxVelocity + nearZero);
+			p.acceleration.z = nearZero;
 		}
     }
     
+    
     /* Define an axis-aligned zone in which entities are not allowed to enter. */
     /* This example zone corresponds to an area to the right of the spawnpoint
     in your Sandbox. It's an area near the big rock to the right. If an entity
     enters the zone, it'll move behind the rock.*/
-    var boxMin = {x: 25.5, y: -0.48, z: -9.9};
-    var boxMax = {x: 31.1, y: 4, z: -3.79};
-    var zero = {x: 0.0, y: 0.0, z: 0.0};
-    
     if (p.position) {
+        /* Random near-zero value used as "zero" to prevent two sequential updates from being
+        exactly the same (which would cause them to be ignored) */
+        var nearZero = 0.0001 * Math.random() + 0.001;
+        /* Define the points that create the "NO ENTITIES ALLOWED" box */
+        var boxMin = {x: 25.5, y: -0.48, z: -9.9};
+        var boxMax = {x: 31.1, y: 4, z: -3.79};
+        /* Define the point that you want entites that enter the box to appear */
+        var resetPoint = {x: 29.5, y: 0.37 + nearZero, z: -2};
         var x = p.position.x;
         var y = p.position.y;
         var z = p.position.z;
         if ((x > boxMin.x && x < boxMax.x) &&
             (y > boxMin.y && y < boxMax.y) &&
             (z > boxMin.z && z < boxMax.z)) {
-            /* Move it to the origin of the zone */
-            p.position = boxMin;
-            p.velocity = zero;
-            p.acceleration = zero;
+            p.position = resetPoint;
+            if (p.velocity) {
+                p.velocity = {x: 0, y: nearZero, z: 0};
+            }
+            if (p.acceleration) {
+                p.acceleration = {x: 0, y: nearZero, z: 0};
+            }
         }
     }