fix(SDK): ensure simulator returns valid play area vertices array

The Simulator was returning a vertices array that was too small and
therefore caused anything that required those vertices to crash.

Also, all SDKs need to return null if a valid vertices array cannot
be obtained so the consuming script can do a null check and prevent
attempting to build something with an invalid vertice array.

Author: thestonefox

Assets/VRTK/SDK/Daydream/SDK_DaydreamBoundaries.cs

@@ -55,16 +55,6 @@ public override Transform GetPlayArea()
         /// <returns>A Vector3 array of the points in the scene that represent the play area boundaries.</returns>
         public override Vector3[] GetPlayAreaVertices(GameObject playArea)
         {
-            if (area)
-            {
-                // taken from SDK_Simulator, is this a valid size? does bounds even make sense in non-positionaly tracked HMD?
-                Vector3[] vertices = new Vector3[4];
-                vertices[0] = new Vector3(1, 0, 1);
-                vertices[1] = new Vector3(-1, 0, 1);
-                vertices[2] = new Vector3(1, 0, -1);
-                vertices[3] = new Vector3(-1, 0, -1);
-                return vertices;
-            }
             return null;
         }
 

Assets/VRTK/SDK/Fallback/SDK_FallbackBoundaries.cs

@@ -34,17 +34,7 @@ public override Transform GetPlayArea()
         /// <returns>A Vector3 array of the points in the scene that represent the play area boundaries.</returns>
         public override Vector3[] GetPlayAreaVertices(GameObject playArea)
         {
-            return new Vector3[8]
-            {
-                Vector3.zero,
-                Vector3.zero,
-                Vector3.zero,
-                Vector3.zero,
-                Vector3.zero,
-                Vector3.zero,
-                Vector3.zero,
-                Vector3.zero
-            };
+            return null;
         }
 
         /// <summary>

Assets/VRTK/SDK/OculusVR/SDK_OculusVRBoundaries.cs

@@ -73,7 +73,7 @@ public override Vector3[] GetPlayAreaVertices(GameObject playArea)
 
                 return vertices;
             }
-            return new Vector3[0];
+            return null;
         }
 
         /// <summary>

Assets/VRTK/SDK/Simulator/SDK_SimBoundaries.cs

@@ -43,16 +43,21 @@ public override Transform GetPlayArea()
         /// <returns>A Vector3 array of the points in the scene that represent the play area boundaries.</returns>
         public override Vector3[] GetPlayAreaVertices(GameObject playArea)
         {
-            if (area)
-            {
-                Vector3[] vertices = new Vector3[4];
-                vertices[0] = new Vector3(1, 0, 1);
-                vertices[1] = new Vector3(-1, 0, 1);
-                vertices[2] = new Vector3(1, 0, -1);
-                vertices[3] = new Vector3(-1, 0, -1);
-                return vertices;
-            }
-            return null;
+            float inner = 0.9f;
+            float outer = 1f;
+
+            Vector3[] vertices = new Vector3[8];
+            vertices[0] = new Vector3(inner, 0f, -inner);
+            vertices[1] = new Vector3(-inner, 0f, -inner);
+            vertices[2] = new Vector3(-inner, 0f, inner);
+            vertices[3] = new Vector3(inner, 0f, inner);
+
+            vertices[4] = new Vector3(outer, 0f, -outer);
+            vertices[5] = new Vector3(-outer, 0f, -outer);
+            vertices[6] = new Vector3(-outer, 0f, outer);
+            vertices[7] = new Vector3(outer, 0f, outer);
+
+            return vertices;
         }
 
         /// <summary>