GLTF Viewer: set camera handness

Author: TheMostDiligent

Samples/Atmosphere/assets/shaders/BasicStructures.fxh

@@ -118,10 +118,11 @@ struct CameraAttribs
     float4 f4Position;     // Camera world position
     float4 f4ViewportSize; // (width, height, 1/width, 1/height)
 
-    float2 f2ViewportOrigin; // (min x, min y)
     float fNearPlaneZ; 
-    float fFarPlaneZ; // fNearPlaneZ < fFarPlaneZ
-
+    float fFarPlaneZ;  // fNearPlaneZ < fFarPlaneZ
+    float fHandness;   // +1.0 for right-handed coordinate system, -1.0 for left-handed
+    float Padding;
+    
 #ifdef __cplusplus
     float4x4 mViewT;
     float4x4 mProjT;

Samples/GLTFViewer/src/GLTFViewer.cpp

@@ -1344,6 +1344,7 @@ void GLTFViewer::Update(double CurrTime, double ElapsedTime)
     const auto& SCDesc = m_pSwapChain->GetDesc();
 
     CurrCamAttribs.f4ViewportSize = float4{static_cast<float>(SCDesc.Width), static_cast<float>(SCDesc.Height), 1.f / SCDesc.Width, 1.f / SCDesc.Height};
+    CurrCamAttribs.fHandness      = CameraView.Determinant() > 0 ? 1.f : -1.f;
     CurrCamAttribs.mViewT         = CameraView.Transpose();
     CurrCamAttribs.mProjT         = CameraProj.Transpose();
     CurrCamAttribs.mViewProjT     = CameraViewProj.Transpose();

Samples/Shadows/assets/shaders/BasicStructures.fxh

@@ -118,10 +118,11 @@ struct CameraAttribs
     float4 f4Position;     // Camera world position
     float4 f4ViewportSize; // (width, height, 1/width, 1/height)
 
-    float2 f2ViewportOrigin; // (min x, min y)
     float fNearPlaneZ; 
-    float fFarPlaneZ; // fNearPlaneZ < fFarPlaneZ
-
+    float fFarPlaneZ;  // fNearPlaneZ < fFarPlaneZ
+    float fHandness;   // +1.0 for right-handed coordinate system, -1.0 for left-handed
+    float Padding;
+    
 #ifdef __cplusplus
     float4x4 mViewT;
     float4x4 mProjT;