Rename vertex color mode option (#6795)

* Rename vertex color mode option

* Update doc

* changelog

Co-authored-by: sebastienlagarde <sebastien@unity3d.com>

Author: adrien-de-tocqueville

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -100,6 +100,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed Show/Hide all Additional Properties
 - Fixed errors about incorrect color spaces in the console when using the Wizzard to fix the project setup (case 1388222).
 - Fixed custom pass name being cut when too long in the inspector.
+- Fixed vertex color mode Add name whicgh was misleading, renamed to AddSubstract.
 
 ## [14.0.0] - 2021-11-17
 

com.unity.render-pipelines.high-definition/Documentation~/snippets/shader-properties/surface-inputs/layered-surface-inputs.md

@@ -6,7 +6,7 @@
 | **World Scale**                              | Set the world-space size of the Texture in meters. If you set this to **1**, then HDRP maps the Texture to 1 meter in world space.If you set this to **2**, then HDRP maps the Texture to 0.5 meters in world space.This property only appears when you select **Planar** or **Triplanar** from the **BlendMask UV Mapping** drop-down. |
 | **Tiling**                                   | Set an **X** and **Y** tile rate for the **Layer Mask** UV. HDRP uses the **X** and **Y** values to tile the Texture assigned to the **Layer Mask** across the Material’s surface, in object space. |
 | **Offset**                                   | Set an **X** and **Y** offset for the **Layer Mask** UV. HDRP uses the **X** and **Y** values to offset the Texture assigned to the **Layer Mask** from the Material’s surface, in object space. |
-| **Vertex Color Mode**                        | Use the drop-down to select the method HDRP uses to combine the **Layer Mask** to manager layer visibility.<br/>&#8226; **None**: Only the **Layer Mask** affects visibility. HDRP does not combine it with vertex colors.<br/>&#8226; **Multiply**: Multiplies the vertex colors from a layer with the corresponding values from the channel in the **Layer Mask** that represents that layer. The default value for a pixel in the mask is 1. Multiplying the vertex colors of a layer by the **Layer Mask** reduces the intensity of that layer, unless the value in the **Layer Mask** is 1.<br/>&#8226; **Add**: Remaps vertex color values to between -1 and 1, and then adds them to the corresponding values from the channel in the **Layer Mask** that represents that layer. Vertex color values between 0 and 0.5 reduce the effect of that layer, values between 0.5 and 1 increase the effect of that layer. |
+| **Vertex Color Mode**                        | Use the drop-down to select the method HDRP uses to combine the **Layer Mask** to manager layer visibility.<br/>&#8226; **None**: Only the **Layer Mask** affects visibility. HDRP does not combine it with vertex colors.<br/>&#8226; **Multiply**: Multiplies the vertex colors from a layer with the corresponding values from the channel in the **Layer Mask** that represents that layer. The default value for a pixel in the mask is 1. Multiplying the vertex colors of a layer by the **Layer Mask** reduces the intensity of that layer, unless the value in the **Layer Mask** is 1.<br/>&#8226; **AddSubstract**: Remaps vertex color values to between -1 and 1, and then adds them to the corresponding values from the channel in the **Layer Mask** that represents that layer. Vertex color values between 0 and 0.5 reduce the effect of that layer, values between 0.5 and 1 increase the effect of that layer. |
 | **Main Layer Influence**                     | Enable the checkbox to allow the **Main Layer** to influence the albedo, normal, and height of **Layer 1**, **Layer 2**, and **Layer 3**. You can change the strength of the influence for each layer. |
 | **Use Height Based Blend**                   | Enable the checkbox to blend the layers with a heightmap. HDRP then evaluates the height of each layer to check whether to display that layer or the layer above. |
 | **Height Transition**                        | Use the slider to set the transition blend size between the Materials in each layer. |

com.unity.render-pipelines.high-definition/Runtime/Material/LayeredLit/LayeredLit.shader

@@ -245,7 +245,7 @@ Shader "HDRP/LayeredLit"
 
         [HideInInspector] _LayerCount("_LayerCount", Float) = 2.0
 
-        [Enum(None, 0, Multiply, 1, Add, 2)] _VertexColorMode("Vertex color mode", Float) = 0
+        [Enum(None, 0, Multiply, 1, AddSubstract, 2)] _VertexColorMode("Vertex color mode", Float) = 0
 
         [ToggleUI]  _ObjectScaleAffectTile("_ObjectScaleAffectTile", Float) = 0.0
         [Enum(UV0, 0, UV1, 1, UV2, 2, UV3, 3, Planar, 4, Triplanar, 5)] _UVBlendMask("UV Set for blendMask", Float) = 0

com.unity.render-pipelines.high-definition/Runtime/Material/LayeredLit/LayeredLitTessellation.shader

@@ -245,7 +245,7 @@ Shader "HDRP/LayeredLitTessellation"
 
         [HideInInspector] _LayerCount("_LayerCount", Float) = 2.0
 
-        [Enum(None, 0, Multiply, 1, Add, 2)] _VertexColorMode("Vertex color mode", Float) = 0
+        [Enum(None, 0, Multiply, 1, AddSubstract, 2)] _VertexColorMode("Vertex color mode", Float) = 0
 
         [ToggleUI]  _ObjectScaleAffectTile("_ObjectScaleAffectTile", Float) = 0.0
         [Enum(UV0, 0, UV1, 1, UV2, 2, UV3, 3, Planar, 4, Triplanar, 5)] _UVBlendMask("UV Set for blendMask", Float) = 0