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, 38 insertions, 0 deletions

diff --git a/tests/spirv/depth-texture.slang b/tests/spirv/depth-texture.slang
new file mode 100644
index 000000000..17204249e
--- /dev/null
+++ b/tests/spirv/depth-texture.slang
@@ -0,0 +1,38 @@
+//TEST:SIMPLE(filecheck=SPIRV): -target spirv
+//TEST:SIMPLE(filecheck=SPIRV): -target spirv -entry psMain -stage pixel
+
+// SPIRV: OpTypeImage %{{.*}} 2D 1 0 0 1 Unknown
+
+__generic<let sampleCount : int = 0, let format : int = 0>
+typealias DepthTexture2D = _Texture<
+    float,
+    __Shape2D,
+    0, // isArray
+    0, // isMS
+    sampleCount,
+    0, // access
+    1, // isShadow
+    0, // isCombined
+    format
+>;
+
+[[vk::binding(0, 0)]] DepthTexture2D depthTexture : register(t0);
+[[vk::binding(1, 0)]] SamplerComparisonState comparisonSampler : register(s0);
+
+[[shader("pixel")]]
+float4 psMain(
+    float4 position : SV_POSITION,
+    float2 texCoord : TEXCOORD0
+) : SV_TARGET {
+    float comparison = depthTexture.SampleCmp(
+        comparisonSampler,
+        texCoord,
+        0.5
+    );
+
+    if (comparison != 0.0) {
+        return float4(1.0, 1.0, 1.0, 1.0);
+    } else {
+        return float4(0.0, 0.0, 0.0, 1.0);
+    }
+}