[Fix] Lens Flare visible when being behind a camera with Panini Projection on (case 1370214) (#6293)

* Fix panini for LensFlare

* Add changelog

Author: skhiat

com.unity.render-pipelines.core/Runtime/PostProcessing/LensFlareCommonSRP.cs

@@ -666,6 +666,12 @@ static public void DoLensFlareDataDrivenCommon(Material lensFlareShader, LensFla
                 }
 
                 Vector3 diffToObject = positionWS - cameraPositionWS;
+                // Check if the light is forward, can be an issue with,
+                // the math associated to Panini projection
+                if (Vector3.Dot(cam.transform.forward, diffToObject) < 0.0f)
+                {
+                    continue;
+                }
                 float distToObject = diffToObject.magnitude;
                 float coefDistSample = distToObject / comp.maxAttenuationDistance;
                 float coefScaleSample = distToObject / comp.maxAttenuationScale;

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

@@ -48,6 +48,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed light unit conversion after changing mid gray value.
 - Fixed Focus distance in path traced depth of field now takes into account the focus mode setting (volume vs camera).
 - Fixed stencil buffer resolve when MSAA is enabled so that OR operator is used instead of picking the last sample.
+- Fixed Lens Flare visible when being behind a camera with Panini Projection on (case 1370214);
 
 ### Changed
 - Maximum light count per fine prunned tile (opaque deferred) is now 63 instead of 23.