DOCG-7115 Improve Scene Depth Difference node docs

Author: markg-unity

Packages/com.unity.shadergraph/Documentation~/Scene-Depth-Difference-Node.md

@@ -1,19 +1,19 @@
-# Scene Depth Difference
+# Scene Depth Difference node
 
-## Description
-
-Provide a difference between a World Space Position and a Depth value for a given UV.
+The Scene Depth Difference node returns the difference in depth between a world space position and a value from the depth buffer.
 
 ## Ports
 
-| Name   | Direction  | Type  | Binding | Description |
-|:-------|:-----------|:------|:--------|:------------|
-| Scene UV | Input     | Vector4 | None    | UV where to sample the depth. |
-| Position WS | Input     | Vector3 | None    | The world space position to compare with scene depth. |
-| Out    | Output     | Float | None    | The difference between PositionWS and the depth. The difference is given relative to camera with **Eye** mode, in depth-buffer-value with **Raw** mode and in Linear value remap between 0 and 1 with the **Linear01** Mode. |
+| **Name** | **Direction** | **Type** | **Binding** | **Description** |
+|-|-|-|-|-|
+| **Scene UV** | Input | Vector 4 | None | Sets the normalized coordinates at which to fetch the scene depth from the depth buffer. The default is the normalized x, y coordinates of the fragment in screen space. For more information about the options, refer to the [Screen Position node](Screen-Position-Node.md). |
+| **Position WS** | Input | Vector 3 | None | Sets the world space position to compare the depth value at **Scene UV** to. The default is the x, y, z position of the fragment in world space. |
+| **Out** | Output | Float | None | The difference in depth between **Scene UV** and **Position WS**. The value depends on the **Sampling mode** property. The distance is negative if the depth value from **Scene UV** is closer to the camera than the depth from **Position WS**. |
 
-## Controls
+## Sampling modes
 
-| Name        | Type           | Options  | Description |
-|:------------ |:-------------|:-----|:---|
-| Mode      | Dropdown | Select **Linear01** to have a value between 0 and 1, **Eye** to have a World-Space value comparable to unit used on the scene and **Raw** if it's used with SceneDepthBuffer. |
+| **Name** | **Description** |
+|----------|------------------------------------|
+| **Linear 01** | Returns the distance in linear normalized space. The minimum distance is 0, and the maximum distance is 1. |
+| **Raw** | Returns the distance in the non-linear space the depth buffer uses. The minimum distance is 0, and the maximum distance is 1. |
+| **Eye** | Returns the distance in meters. |