HD/Decals: allows negative UV

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

@@ -135,6 +135,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed a bug with Reflection Probe baking would result in an incorrect baking reusing other's Reflection Probe baking
 - Fixed volumetric fog being visually chopped or missing when using hardware Dynamic Resolution Scaling.
 - Fixed generation of the packed depth pyramid when hardware Dynamic Resolution Scaling is enabled.
+- Fixed Decal's UV edit mode with negative UV
 
 ### Changed
 - Changed Window/Render Pipeline/HD Render Pipeline Wizard to Window/Rendering/HDRP Wizard

com.unity.render-pipelines.high-definition/Editor/Material/Decal/DecalProjectorEditor.cs

@@ -119,7 +119,7 @@ static DisplacableRectHandles uvHandles
             get
             {
                 if (s_uvHandles == null || s_uvHandles.Equals(null))
-                    s_uvHandles = new DisplacableRectHandles(s_LastColor);
+                    s_uvHandles = new DisplacableRectHandles(s_LastColor, allowsNegative: true);
                 return s_uvHandles;
             }
         }

com.unity.render-pipelines.high-definition/Editor/Material/Decal/DisplacableRectHandles.cs

@@ -15,6 +15,7 @@ enum NamedEdge { Right, Top, Left, Bottom, None }
         Color m_MonochromeHandleColor;
         Color m_WireframeColor;
         Color m_WireframeColorBehind;
+        bool allowsNegative;
 
         /// <summary>The position of the center of the box in Handle.matrix space. On plane z=0.</summary>
         public Vector2 center { get; set; }
@@ -58,9 +59,10 @@ public Color baseColor
             }
         }
 
-        public DisplacableRectHandles(Color baseColor)
+        public DisplacableRectHandles(Color baseColor, bool allowsNegative = false)
         {
             this.baseColor = baseColor;
+            this.allowsNegative = allowsNegative;
         }
 
         /// <summary>Draw the rect.</summary>
@@ -258,7 +260,8 @@ public void DrawHandle()
                             case NamedEdge.Bottom: topPosition.y -= delta; break;
                         }
 
-                        EnsureEdgeFacesOutsideForSymetry(theChangedEdge, ref leftPosition, ref rightPosition, ref topPosition, ref bottomPosition);
+                        if (!allowsNegative)
+                            EnsureEdgeFacesOutsideForSymetry(theChangedEdge, ref leftPosition, ref rightPosition, ref topPosition, ref bottomPosition);
                     }
 
                     if (useHomothety)
@@ -278,13 +281,14 @@ public void DrawHandle()
                                 break;
                         }
 
-                        EnsureEdgeFacesOutsideForHomothety(theChangedEdge, ref leftPosition, ref rightPosition, ref topPosition, ref bottomPosition);
+                        if (!allowsNegative)
+                            EnsureEdgeFacesOutsideForHomothety(theChangedEdge, ref leftPosition, ref rightPosition, ref topPosition, ref bottomPosition);
                     }
 
                     var max = new Vector2(rightPosition.x, topPosition.y);
                     var min = new Vector2(leftPosition.x, bottomPosition.y);
 
-                    if (!useSymetry && !useHomothety)
+                    if (!useSymetry && !useHomothety && !allowsNegative)
                         EnsureEdgeFacesOutsideForOtherTransformation(ref max, ref min);
 
                     center = (max + min) * .5f;