Vulkan: Bug fix in GL_QCOM_shading_rate

A default value of _1x1 for mShadingRate interacts badly with sample
shading state on some vendors. Instead set the default to Undefined
and return early in such cases.

Bug: angleproject:7172
Change-Id: If0a280090e6611817d2f5d75929ef2b654ddb186
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3658245
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: mohan maiya <m.maiya@samsung.com>

scripts/code_generation_hashes/packed_enum.json

@@ -8,9 +8,9 @@
   "src/common/PackedEGLEnums_autogen.h":
     "7d87e160a0c8ea26cb0c835729f7b586",
   "src/common/PackedGLEnums_autogen.cpp":
-    "81a3c830e3d832b00b2f68131f252705",
+    "ff47808f52d3d9bc870cfa919880342d",
   "src/common/PackedGLEnums_autogen.h":
-    "33354eaef83bda2fcd9c623e9e8cc773",
+    "81e65899f1a783d0be372b54fadb07be",
   "src/common/gen_packed_gl_enums.py":
     "27df356513bc2f377b78655113d17c7e",
   "src/common/packed_cl_enums.json":
@@ -18,5 +18,5 @@
   "src/common/packed_egl_enums.json":
     "5797db941e95e418d69527eb4e4af900",
   "src/common/packed_gl_enums.json":
-    "a8eebbfc9a8a703fa3e54bb29d125649"
+    "50c963b42474cd6742e112bbe0a53396"
 }

src/common/PackedGLEnums_autogen.cpp

@@ -1508,6 +1508,8 @@ ShadingRate FromGLenum<ShadingRate>(GLenum from)
 {
     switch (from)
     {
+        case GL_NONE:
+            return ShadingRate::Undefined;
         case GL_SHADING_RATE_1X1_PIXELS_QCOM:
             return ShadingRate::_1x1;
         case GL_SHADING_RATE_1X2_PIXELS_QCOM:
@@ -1529,6 +1531,8 @@ GLenum ToGLenum(ShadingRate from)
 {
     switch (from)
     {
+        case ShadingRate::Undefined:
+            return GL_NONE;
         case ShadingRate::_1x1:
             return GL_SHADING_RATE_1X1_PIXELS_QCOM;
         case ShadingRate::_1x2:
@@ -1551,6 +1555,9 @@ std::ostream &operator<<(std::ostream &os, ShadingRate value)
 {
     switch (value)
     {
+        case ShadingRate::Undefined:
+            os << "GL_NONE";
+            break;
         case ShadingRate::_1x1:
             os << "GL_SHADING_RATE_1X1_PIXELS_QCOM";
             break;

src/common/PackedGLEnums_autogen.h

@@ -389,15 +389,16 @@ std::ostream &operator<<(std::ostream &os, ShadingModel value);
 
 enum class ShadingRate : uint8_t
 {
-    _1x1 = 0,
-    _1x2 = 1,
-    _2x1 = 2,
-    _2x2 = 3,
-    _4x2 = 4,
-    _4x4 = 5,
+    Undefined = 0,
+    _1x1      = 1,
+    _1x2      = 2,
+    _2x1      = 3,
+    _2x2      = 4,
+    _4x2      = 5,
+    _4x4      = 6,
 
-    InvalidEnum = 6,
-    EnumCount   = 6,
+    InvalidEnum = 7,
+    EnumCount   = 7,
 };
 
 template <>

src/common/packed_gl_enums.json

@@ -294,6 +294,7 @@
     },
     "ShadingRate":
     {
+        "Undefined": "GL_NONE",
         "_1x1": "GL_SHADING_RATE_1X1_PIXELS_QCOM",
         "_1x2": "GL_SHADING_RATE_1X2_PIXELS_QCOM",
         "_2x1": "GL_SHADING_RATE_2X1_PIXELS_QCOM",

src/libANGLE/State.cpp

@@ -420,7 +420,7 @@ State::State(const State *shareContextState,
       mBoundingBoxMaxZ(1.0f),
       mBoundingBoxMaxW(1.0f),
       mShadingRatePreserveAspectRatio(false),
-      mShadingRate(ShadingRate::_1x1)
+      mShadingRate(ShadingRate::Undefined)
 {}
 
 State::~State() {}

src/libANGLE/renderer/vulkan/ContextVk.cpp

@@ -2727,7 +2727,13 @@ angle::Result ContextVk::handleDirtyGraphicsDynamicFragmentShadingRate(
     DirtyBits::Iterator *dirtyBitsIterator,
     DirtyBits dirtyBitMask)
 {
-    gl::ShadingRate shadingRate     = getState().getShadingRate();
+    gl::ShadingRate shadingRate = getState().getShadingRate();
+    if (shadingRate == gl::ShadingRate::Undefined)
+    {
+        // Shading rate has not been set. Nothing to do, early return.
+        return angle::Result::Continue;
+    }
+
     const bool shadingRateSupported = mRenderer->isShadingRateSupported(shadingRate);
     VkExtent2D fragmentSize         = {};
     VkFragmentShadingRateCombinerOpKHR shadingRateCombinerOp[2] = {

src/libANGLE/validationESEXT.cpp

@@ -3039,7 +3039,8 @@ bool ValidateShadingRateQCOM(const Context *context, angle::EntryPoint entryPoin
         return false;
     }
 
-    if (gl::FromGLenum<gl::ShadingRate>(rate) == gl::ShadingRate::InvalidEnum)
+    gl::ShadingRate shadingRate = gl::FromGLenum<gl::ShadingRate>(rate);
+    if (shadingRate == gl::ShadingRate::Undefined || shadingRate == gl::ShadingRate::InvalidEnum)
     {
         context->validationError(entryPoint, GL_INVALID_ENUM, kInvalidShadingRate);
         return false;