Don't add `flat` qualifier to integer fragment output

Fixes #133

We already had logic to skip adding `flat` to a vertex input, and this just extends it to not adding `flat` to a fragment output.

Note that explicit qualifiers in the input HLSL/Slang will still be carried through to the output, so it is still possible for a Slang user to shoot themself in the foot with interpolation qualifiers.

1 files changed, 7 insertions, 2 deletions

diff --git a/source/slang/lower.cpp b/source/slang/lower.cpp
index 174c93c1d..9c2c38b60 100644
--- a/source/slang/lower.cpp
+++ b/source/slang/lower.cpp
@@ -3582,9 +3582,14 @@ struct LoweringVisitor
             else if (isIntegralType(varType))
             {
                 if (info.direction == VaryingParameterDirection::Input
-                    && shared->entryPointRequest->profile.GetStage() == Stage::Vertex)
+                    && shared->entryPointRequest->profile.GetStage() != Stage::Fragment)
                 {
-                    // Don't add extra qualification to VS inputs
+                    // Don't add extra qualification to vertex shader inputs
+                }
+                else if (info.direction == VaryingParameterDirection::Output
+                    && shared->entryPointRequest->profile.GetStage() == Stage::Fragment)
+                {
+                    // Don't add extra qualification to fragment shader outputs
                 }
                 else
                 {