Changed the occlusion culling plane model to be on the XZ plane and adjusted the corner point computations

Gems/Atom/Feature/Common/Assets/Models/OcclusionCullingPlane.fbx

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:0a1f8d75dcd85e8b4aa57f6c0c81af0300ff96915ba3c2b591095c215d5e1d8c
-size 12072
+oid sha256:75cdf73fcb9698a76a38294a1cf927a4fb41a34869e0429e1f02bf8d361a7258
+size 20400

Gems/Atom/Feature/Common/Code/Source/OcclusionCullingPlane/OcclusionCullingPlaneFeatureProcessor.cpp

@@ -64,18 +64,18 @@ namespace AZ
 
                     RPI::CullingScene::OcclusionPlane rpiOcclusionPlane;
 
-                    static const Vector3 BL = Vector3(-0.5f, -0.5f, 0.0f);
-                    static const Vector3 BR = Vector3(0.5f, -0.5f, 0.0f);
-                    static const Vector3 TL = Vector3(-0.5f, 0.5f, 0.0f);
-                    static const Vector3 TR = Vector3(0.5f, 0.5f, 0.0f);
+                    static const Vector3 BL = Vector3(-0.5f, 0.0f, -0.5f);
+                    static const Vector3 TL = Vector3(-0.5f, 0.0f,  0.5f);
+                    static const Vector3 TR = Vector3( 0.5f, 0.0f,  0.5f);
+                    static const Vector3 BR = Vector3( 0.5f, 0.0f, -0.5f);
 
                     const AZ::Transform& transform = occlusionCullingPlane->GetTransform();
 
                     // convert corners to world space
                     rpiOcclusionPlane.m_cornerBL = transform.TransformPoint(BL);
-                    rpiOcclusionPlane.m_cornerBR = transform.TransformPoint(BR);
                     rpiOcclusionPlane.m_cornerTL = transform.TransformPoint(TL);
                     rpiOcclusionPlane.m_cornerTR = transform.TransformPoint(TR);
+                    rpiOcclusionPlane.m_cornerBR = transform.TransformPoint(BR);
 
                     // build world space AABB
                     AZ::Vector3 aabbMin = rpiOcclusionPlane.m_cornerBL.GetMin(rpiOcclusionPlane.m_cornerTR);

Gems/Atom/RPI/Code/Include/Atom/RPI.Public/Culling.h

@@ -219,9 +219,9 @@ namespace AZ
             {
                 // World space corners of the occluson plane
                 Vector3 m_cornerBL;
-                Vector3 m_cornerBR;
                 Vector3 m_cornerTL;
                 Vector3 m_cornerTR;
+                Vector3 m_cornerBR;
 
                 Aabb m_aabb;
             };

Gems/Atom/RPI/Code/Source/RPI.Public/Culling.cpp

@@ -574,18 +574,18 @@ namespace AZ
                 {
                     // convert to clip-space
                     Vector4 projectedBL = view.GetWorldToClipMatrix() * Vector4(occlusionPlane.first.m_cornerBL);
-                    Vector4 projectedBR = view.GetWorldToClipMatrix() * Vector4(occlusionPlane.first.m_cornerBR);
                     Vector4 projectedTL = view.GetWorldToClipMatrix() * Vector4(occlusionPlane.first.m_cornerTL);
                     Vector4 projectedTR = view.GetWorldToClipMatrix() * Vector4(occlusionPlane.first.m_cornerTR);
+                    Vector4 projectedBR = view.GetWorldToClipMatrix() * Vector4(occlusionPlane.first.m_cornerBR);
 
                     // store to float array
                     float verts[16];
                     projectedBL.StoreToFloat4(&verts[0]);
-                    projectedBR.StoreToFloat4(&verts[4]);
-                    projectedTL.StoreToFloat4(&verts[8]);
-                    projectedTR.StoreToFloat4(&verts[12]);
+                    projectedTL.StoreToFloat4(&verts[4]);
+                    projectedTR.StoreToFloat4(&verts[8]);
+                    projectedBR.StoreToFloat4(&verts[12]);
 
-                    static uint32_t indices[6] = { 0, 2, 1, 2, 3, 1 };
+                    static uint32_t indices[6] = { 0, 1, 2, 2, 3, 0 };
 
                     // render into the occlusion buffer, specifying BACKFACE_NONE so it functions as a double-sided occluder
                     maskedOcclusionCulling->RenderTriangles((float*)verts, indices, 2, nullptr, MaskedOcclusionCulling::BACKFACE_NONE);