GLTF Viewer: use opacity in alpha channel

Author: TheMostDiligent

Samples/GLTFViewer/assets/shaders/ApplyPostEffects.psh

@@ -49,7 +49,7 @@ float4 main(in FullScreenTriangleVSOutput VSOut) : SV_Target
 
     float3 SSR = GetSpecularIBL_GGX(SrfInfo, IBLInfo, SSRRadiance.rgb);
 
-    float Opacity = 1.0 - OutColor.a;
+    float Opacity = OutColor.a;
     if (DebugMode == 0.0)
     {
         OutColor.rgb += (SSR.rgb - SpecularIBL.rgb) * SSRRadiance.w * Opacity * SSRScale;
@@ -85,6 +85,5 @@ float4 main(in FullScreenTriangleVSOutput VSOut) : SV_Target
     }
 #endif
 
-    OutColor.a = 1.0;
     return OutColor;
 }

Samples/GLTFViewer/src/GLTFViewer.cpp

@@ -1162,7 +1162,7 @@ void GLTFViewer::Render()
     else
     {
         // Clear the back buffer
-        const float ClearColor[] = {0.032f, 0.032f, 0.032f, 1.0f};
+        const float ClearColor[] = {0.032f, 0.032f, 0.032f, 0.0f};
         m_pImmediateContext->ClearRenderTarget(pRTV, ClearColor, RESOURCE_STATE_TRANSITION_MODE_TRANSITION);
         m_pImmediateContext->ClearDepthStencil(pDSV, CLEAR_DEPTH_FLAG, 1.f, 0, RESOURCE_STATE_TRANSITION_MODE_TRANSITION);
     }
@@ -1324,7 +1324,7 @@ void GLTFViewer::Render()
         EnvMapAttribs.pEnvMap       = pEnvMapSRV;
         EnvMapAttribs.AverageLogLum = m_ShaderAttribs.AverageLogLum;
         EnvMapAttribs.MipLevel      = m_EnvMapMipLevel;
-        EnvMapAttribs.Alpha         = 1.0;
+        EnvMapAttribs.Alpha         = 0.0;
         if ((m_RenderParams.Flags & GLTF_PBR_Renderer::PSO_FLAG_CONVERT_OUTPUT_TO_SRGB) != 0)
             EnvMapAttribs.Options |= EnvMapRenderer::OPTION_FLAG_CONVERT_OUTPUT_TO_SRGB;
         if (m_bEnablePostProcessing)
@@ -1394,7 +1394,7 @@ void GLTFViewer::Render()
 
         m_pImmediateContext->SetRenderTargets(1, &pRTV, nullptr, RESOURCE_STATE_TRANSITION_MODE_TRANSITION);
         // Clear the back buffer
-        const float ClearColor[] = {0.032f, 0.032f, 0.032f, 1.0f};
+        const float ClearColor[] = {0.032f, 0.032f, 0.032f, 0.0f};
         m_pImmediateContext->ClearRenderTarget(pRTV, ClearColor, RESOURCE_STATE_TRANSITION_MODE_TRANSITION);
 
         m_pImmediateContext->SetPipelineState(m_ApplyPostFX.pPSO);