From 97963c5c119a3445fa6353809669d4553952e66c Mon Sep 17 00:00:00 2001
From: jsmall-nvidia <jsmall@nvidia.com>
Date: Wed, 28 Jun 2023 07:39:31 -0400
Subject: Add support for vk::image_format attribute (#2945)

---
 source/slang/slang-syntax.cpp | 49 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 45 insertions(+), 4 deletions(-)

(limited to 'source/slang/slang-syntax.cpp')

diff --git a/source/slang/slang-syntax.cpp b/source/slang/slang-syntax.cpp
index 606c77096..53e77e646 100644
--- a/source/slang/slang-syntax.cpp
+++ b/source/slang/slang-syntax.cpp
@@ -1434,10 +1434,8 @@ static const ImageFormatInfo kImageFormatInfos[] =
 #undef SLANG_IMAGE_FORMAT_INFO
 };
 
-bool findImageFormatByName(char const* inName, ImageFormat* outFormat)
+bool findImageFormatByName(const UnownedStringSlice& name, ImageFormat* outFormat)
 {
-    const UnownedStringSlice name(inName);
-
     for (Index i = 0; i < SLANG_COUNT_OF(kImageFormatInfos); ++i)
     {
         const auto& info = kImageFormatInfos[i];
@@ -1450,12 +1448,55 @@ bool findImageFormatByName(char const* inName, ImageFormat* outFormat)
     return false;
 }
 
+// https://github.com/microsoft/DirectXShaderCompiler/blob/main/docs/SPIR-V.rst#id71
+#define SLANG_VK_TO_IMAGE_FORMAT(x) \
+    x(r11g11b10f, r11f_g11f_b10f) \
+    x(rgb10a2, rgb10_a2) \
+    x(rgb10a2ui, rgb10_a2ui) 
+
+struct VkImageFormatInfo
+{
+    UnownedStringSlice name;
+    ImageFormat format;
+};
+static const VkImageFormatInfo kVkImageFormatInfos[] =
+{
+#define SLANG_VK_IMAGE_FORMAT_INFO(name, format) { toSlice(#name), ImageFormat::format },
+    SLANG_VK_TO_IMAGE_FORMAT(SLANG_VK_IMAGE_FORMAT_INFO)
+};
+
+static const auto kSNorm = UnownedStringSlice::fromLiteral("snorm");
+
+bool findVkImageFormatByName(const UnownedStringSlice& name, ImageFormat* outFormat)
+{
+    // Handle names ending in snorm
+    if (name.endsWith(kSNorm))
+    {
+        StringBuilder buf;
+        //  format names end with snormal after a '_', so replace with that
+        buf << name.head(name.getLength() - kSNorm.getLength()) << "_" << kSNorm;
+        return findImageFormatByName(buf.getUnownedSlice(), outFormat);
+    }
+    
+    // Handle the special cases
+    for (const auto& vkInfo : kVkImageFormatInfos)
+    {
+        if (vkInfo.name == name)
+        {
+            *outFormat = vkInfo.format;
+            return true;
+        }
+    }
+
+    // Default to the regular lookup mechanism for everything else
+    return findImageFormatByName(name, outFormat);
+}
+
 char const* getGLSLNameForImageFormat(ImageFormat format)
 {
     return kImageFormatInfos[Index(format)].name.begin();
 }
 
-
 const ImageFormatInfo& getImageFormatInfo(ImageFormat format)
 {
     return kImageFormatInfos[Index(format)];
-- 
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