Respect isShadow() flag when setting depth type in SPIR-V backend (#8604)

This is important for SPIR-V targets that need to know if a texture is
designated as a depth texture or not (for example WebGPU).

I didn't change the default behavior for when isShadow() is not set,
since I didn't want to make the change too invasive.

1 files changed, 5 insertions, 1 deletions

diff --git a/source/slang/slang-emit-spirv.cpp b/source/slang/slang-emit-spirv.cpp
index b3232de93..36368c3ee 100644
--- a/source/slang/slang-emit-spirv.cpp
+++ b/source/slang/slang-emit-spirv.cpp
@@ -2681,7 +2681,11 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex
 
         // Vulkan spec 16.1: "The “Depth” operand of OpTypeImage is ignored."
         SpvWord depth =
-            ImageOpConstants::unknownDepthImage; // No knowledge of if this is a depth image
+            inst->isShadow()
+                ? ImageOpConstants::isDepthImage       // But we respect the `isShadow` flag of the
+                                                       // texture
+                : ImageOpConstants::unknownDepthImage; // No knowledge of if this is a depth image
+
         SpvWord ms = inst->isMultisample() ? ImageOpConstants::isMultisampled
                                            : ImageOpConstants::notMultisampled;