Vulkan: Add OES_shader_multisample_interpolation support

Support OES_shader_multisample_interpolation extension if
maxInterpolationOffset >= 0.5

Bug: angleproject:3589
Tests: dEQP-GLES31.functional.shaders.multisample_interpolation.*
       dEQP-GLES31.functional.state_query.multisample_interpolation.*
Change-Id: I42997f10be82e3be8b63c56833cbbf791bf4be9b
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2477905
Commit-Queue: Mohan Maiya <m.maiya@samsung.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>

include/GLSLANG/ShaderVars.h

@@ -28,6 +28,7 @@ enum InterpolationType
 {
     INTERPOLATION_SMOOTH,
     INTERPOLATION_CENTROID,
+    INTERPOLATION_SAMPLE,
     INTERPOLATION_FLAT,
     INTERPOLATION_NOPERSPECTIVE
 };

src/compiler/translator/BaseTypes.h

@@ -981,10 +981,12 @@ enum TQualifier
     EvqFlatOut,
     EvqNoPerspectiveOut,
     EvqCentroidOut,  // Implies smooth
+    EvqSampleOut,
     EvqSmoothIn,
     EvqFlatIn,
     EvqNoPerspectiveIn,
     EvqCentroidIn,  // Implies smooth
+    EvqSampleIn,
 
     // GLSL ES 3.1 compute shader special variables
     EvqShared,
@@ -1042,6 +1044,7 @@ inline bool IsShaderIn(TQualifier qualifier)
         case EvqFlatIn:
         case EvqNoPerspectiveIn:
         case EvqCentroidIn:
+        case EvqSampleIn:
             return true;
         default:
             return false;
@@ -1060,6 +1063,7 @@ inline bool IsShaderOut(TQualifier qualifier)
         case EvqFlatOut:
         case EvqNoPerspectiveOut:
         case EvqCentroidOut:
+        case EvqSampleOut:
             return true;
         default:
             return false;
@@ -1333,6 +1337,9 @@ inline const char *getQualifierString(TQualifier q)
     case EvqPerVertexIn:            return "gl_in";
     case EvqPrecise:                return "precise";
     case EvqClipDistance:           return "ClipDistance";
+    case EvqSample:                 return "sample";
+    case EvqSampleIn:               return "sample in";
+    case EvqSampleOut:              return "sample out";
     default: UNREACHABLE();         return "unknown qualifier";
     }
     // clang-format on

src/compiler/translator/CollectVariables.cpp

@@ -732,6 +732,7 @@ ShaderVariable CollectVariablesTraverser::recordVarying(const TIntermSymbol &var
         case EvqNoPerspectiveOut:
         case EvqCentroidOut:
         case EvqGeometryOut:
+        case EvqSampleOut:
             if (mSymbolTable->isVaryingInvariant(variable.variable()) || type.isInvariant())
             {
                 varying.isInvariant = true;

src/compiler/translator/Compiler.cpp

@@ -1090,6 +1090,7 @@ void TCompiler::setResourceString()
         << ":OES_texture_cube_map_array:" << mResources.OES_texture_cube_map_array
         << ":EXT_texture_cube_map_array:" << mResources.EXT_texture_cube_map_array
         << ":EXT_shadow_samplers:" << mResources.EXT_shadow_samplers
+        << ":OES_shader_multisample_interpolation:" << mResources.OES_shader_multisample_interpolation
         << ":MinProgramTextureGatherOffset:" << mResources.MinProgramTextureGatherOffset
         << ":MaxProgramTextureGatherOffset:" << mResources.MaxProgramTextureGatherOffset
         << ":MaxImageUnits:" << mResources.MaxImageUnits

src/compiler/translator/Initialize.cpp

@@ -129,6 +129,10 @@ void InitExtensionBehavior(const ShBuiltInResources &resources, TExtensionBehavi
     {
         extBehavior[TExtension::EXT_shadow_samplers] = EBhUndefined;
     }
+    if (resources.OES_shader_multisample_interpolation)
+    {
+        extBehavior[TExtension::OES_shader_multisample_interpolation] = EBhUndefined;
+    }
 }
 
 void ResetExtensionBehavior(const ShBuiltInResources &resources,

src/compiler/translator/ParseContext.cpp

@@ -128,6 +128,26 @@ bool IsBufferOrSharedVariable(TIntermTyped *var)
     return false;
 }
 
+TIntermTyped *FindLValueBase(TIntermTyped *node)
+{
+    do
+    {
+        const TIntermBinary *binary = node->getAsBinaryNode();
+        if (binary == nullptr)
+        {
+            return node;
+        }
+
+        TOperator op = binary->getOp();
+        if (op != EOpIndexDirect && op != EOpIndexIndirect)
+        {
+            return static_cast<TIntermTyped *>(nullptr);
+        }
+
+        node = binary->getLeft();
+    } while (true);
+}
+
 }  // namespace
 
 // This tracks each binding point's current default offset for inheritance of subsequent
@@ -534,6 +554,7 @@ bool TParseContext::checkCanBeLValue(const TSourceLoc &line, const char *op, TIn
         case EvqNoPerspectiveIn:
         case EvqSmoothIn:
         case EvqCentroidIn:
+        case EvqSampleIn:
             message = "can't modify an input";
             break;
         case EvqUniform:
@@ -5983,6 +6004,41 @@ void TParseContext::checkSingleTextureOffset(const TSourceLoc &line,
     }
 }
 
+void TParseContext::checkInterpolationFS(TIntermAggregate *functionCall)
+{
+    const TFunction *func = functionCall->getFunction();
+    if (!BuiltInGroup::isInterpolationFS(func))
+    {
+        return;
+    }
+
+    TIntermTyped *arg0 = nullptr;
+
+    if (functionCall->getAsAggregate())
+    {
+        const TIntermSequence *argp = functionCall->getSequence();
+        if (argp->size() > 0)
+            arg0 = (*argp)[0]->getAsTyped();
+    }
+    else
+    {
+        assert(functionCall->getAsUnaryNode());
+        arg0 = functionCall->getAsUnaryNode()->getOperand();
+    }
+
+    // Make sure the first argument is an interpolant, or an array element of an interpolant
+    if (!IsVaryingIn(arg0->getType().getQualifier()))
+    {
+        // It might still be an array element.
+        const TIntermTyped *base = FindLValueBase(arg0);
+
+        if (base == nullptr || (!IsVaryingIn(base->getType().getQualifier())))
+            error(arg0->getLine(),
+                  "first argument must be an interpolant, or interpolant-array element",
+                  func->name());
+    }
+}
+
 void TParseContext::checkAtomicMemoryBuiltinFunctions(TIntermAggregate *functionCall)
 {
     const TFunction *func = functionCall->getFunction();
@@ -6248,6 +6304,7 @@ TIntermTyped *TParseContext::addNonConstructorFunctionCall(TFunctionLookup *fnCa
             callNode->setLine(loc);
             checkTextureOffset(callNode);
             checkTextureGather(callNode);
+            checkInterpolationFS(callNode);
             checkImageMemoryAccessForBuiltinFunctions(callNode);
             functionCallRValueLValueErrorCheck(fnCandidate, callNode);
             return callNode;

src/compiler/translator/ParseContext.h

@@ -441,6 +441,7 @@ class TParseContext : angle::NonCopyable
     void checkImageMemoryAccessForUserDefinedFunctions(const TFunction *functionDefinition,
                                                        const TIntermAggregate *functionCall);
     void checkAtomicMemoryBuiltinFunctions(TIntermAggregate *functionCall);
+    void checkInterpolationFS(TIntermAggregate *functionCall);
 
     // fnCall is only storing the built-in op, and function name or constructor type. arguments
     // has the arguments.

src/compiler/translator/QualifierTypes.cpp

@@ -440,6 +440,23 @@ bool JoinVariableStorageQualifier(TQualifier *joinedQualifier, TQualifier storag
             }
             break;
         }
+        case EvqSample:
+        {
+            switch (storageQualifier)
+            {
+                case EvqVertexOut:
+                case EvqGeometryOut:
+                    *joinedQualifier = EvqSampleOut;
+                    break;
+                case EvqFragmentIn:
+                case EvqGeometryIn:
+                    *joinedQualifier = EvqSampleIn;
+                    break;
+                default:
+                    return false;
+            }
+            break;
+        }
         default:
             return false;
     }

src/compiler/translator/UtilsHLSL.cpp

@@ -1063,6 +1063,8 @@ const char *InterpolationString(TQualifier qualifier)
             return "nointerpolation";
         case EvqCentroidOut:
             return "centroid";
+        case EvqSampleIn:
+            return "sample";
         default:
             UNREACHABLE();
     }
@@ -1083,6 +1085,8 @@ const char *QualifierString(TQualifier qualifier)
             return "inout";
         case EvqConstReadOnly:
             return "const";
+        case EvqSampleOut:
+            return "sample";
         default:
             UNREACHABLE();
     }

src/compiler/translator/util.cpp

@@ -35,6 +35,7 @@ bool IsInterpolationIn(TQualifier qualifier)
         case EvqFlatIn:
         case EvqNoPerspectiveIn:
         case EvqCentroidIn:
+        case EvqSampleIn:
             return true;
         default:
             return false;
@@ -538,6 +539,7 @@ bool IsVaryingOut(TQualifier qualifier)
         case EvqCentroidOut:
         case EvqVertexOut:
         case EvqGeometryOut:
+        case EvqSampleOut:
             return true;
 
         default:
@@ -558,6 +560,7 @@ bool IsVaryingIn(TQualifier qualifier)
         case EvqCentroidIn:
         case EvqFragmentIn:
         case EvqGeometryIn:
+        case EvqSampleIn:
             return true;
 
         default:
@@ -604,6 +607,9 @@ InterpolationType GetInterpolationType(TQualifier qualifier)
         case EvqCentroidOut:
             return INTERPOLATION_CENTROID;
 
+        case EvqSampleIn:
+        case EvqSampleOut:
+            return INTERPOLATION_SAMPLE;
         default:
             UNREACHABLE();
 #if !UNREACHABLE_IS_NORETURN

src/libANGLE/Caps.cpp

@@ -1036,6 +1036,7 @@ const ExtensionInfoMap &GetExtensionInfoMap()
         map["GL_EXT_buffer_storage"] = enableableExtension(&Extensions::bufferStorageEXT);
         map["GL_OES_texture_stencil8"] = enableableExtension(&Extensions::stencilIndex8);
         map["GL_OES_sample_shading"] = enableableExtension(&Extensions::sampleShadingOES);
+        map["GL_OES_shader_multisample_interpolation"] = enableableExtension(&Extensions::multisampleInterpolationOES);
         map["GL_NV_robustness_video_memory_purge"] = esOnlyExtension(&Extensions::robustnessVideoMemoryPurgeNV);
         map["GL_ANGLE_get_tex_level_parameter"] = enableableExtension(&Extensions::getTexLevelParameterANGLE);
         // GLES1 extensions

src/libANGLE/Caps.h

@@ -654,6 +654,9 @@ struct Extensions
     // GL_OES_sample_shading
     bool sampleShadingOES = false;
 
+    // OES_shader_multisample_interpolation
+    bool multisampleInterpolationOES = false;
+
     // GL_NV_robustness_video_memory_purge
     bool robustnessVideoMemoryPurgeNV = false;
 
@@ -746,6 +749,10 @@ struct Caps
     // be GLint instead of GLuint and call LimitToInt() to ensure
     // they will not overflow.
 
+    GLfloat minInterpolationOffset        = 0;
+    GLfloat maxInterpolationOffset        = 0;
+    GLint subPixelInterpolationOffsetBits = 0;
+
     // ES 3.1 (April 29, 2015) 20.39: implementation dependent values
     GLint64 maxElementIndex       = 0;
     GLint max3DTextureSize        = 0;

src/libANGLE/Compiler.cpp

@@ -110,7 +110,8 @@ Compiler::Compiler(rx::GLImplFactory *implFactory, const State &state, egl::Disp
     mResources.ANGLE_multi_draw                = extensions.multiDraw;
     mResources.ANGLE_base_vertex_base_instance = extensions.baseVertexBaseInstance;
     mResources.APPLE_clip_distance             = extensions.clipDistanceAPPLE;
-
+    // OES_shader_multisample_interpolation
+    mResources.OES_shader_multisample_interpolation = extensions.multisampleInterpolationOES;
     // TODO: use shader precision caps to determine if high precision is supported?
     mResources.FragmentPrecisionHigh = 1;
     mResources.EXT_frag_depth        = extensions.fragDepth;

src/libANGLE/Context.cpp

@@ -1419,6 +1419,12 @@ void Context::getFloatvImpl(GLenum pname, GLfloat *params) const
         case GL_MAX_TEXTURE_LOD_BIAS:
             *params = mState.mCaps.maxLODBias;
             break;
+        case GL_MIN_FRAGMENT_INTERPOLATION_OFFSET:
+            *params = mState.mCaps.minInterpolationOffset;
+            break;
+        case GL_MAX_FRAGMENT_INTERPOLATION_OFFSET:
+            *params = mState.mCaps.maxInterpolationOffset;
+            break;
         default:
             mState.getFloatv(pname, params);
             break;
@@ -1850,7 +1856,10 @@ void Context::getIntegervImpl(GLenum pname, GLint *params) const
         case GL_MAX_DUAL_SOURCE_DRAW_BUFFERS_EXT:
             *params = mState.mExtensions.maxDualSourceDrawBuffers;
             break;
-
+        // OES_shader_multisample_interpolation
+        case GL_FRAGMENT_INTERPOLATION_OFFSET_BITS_OES:
+            *params = mState.mCaps.subPixelInterpolationOffsetBits;
+            break;
         default:
             ANGLE_CONTEXT_TRY(mState.getIntegerv(this, pname, params));
             break;

src/libANGLE/queryutils.cpp

@@ -3567,6 +3567,7 @@ bool GetQueryParameterInfo(const State &glState,
         case GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS:
         case GL_UNPACK_IMAGE_HEIGHT:
         case GL_UNPACK_SKIP_IMAGES:
+        case GL_FRAGMENT_INTERPOLATION_OFFSET_BITS_OES:
         {
             *type      = GL_INT;
             *numParams = 1;
@@ -3595,6 +3596,8 @@ bool GetQueryParameterInfo(const State &glState,
         }
 
         case GL_MAX_TEXTURE_LOD_BIAS:
+        case GL_MIN_FRAGMENT_INTERPOLATION_OFFSET_OES:
+        case GL_MAX_FRAGMENT_INTERPOLATION_OFFSET_OES:
         {
             *type      = GL_FLOAT;
             *numParams = 1;

src/libANGLE/renderer/d3d/DynamicHLSL.cpp

@@ -435,6 +435,9 @@ void DynamicHLSL::generateVaryingLinkHLSL(const VaryingPacking &varyingPacking,
             case sh::INTERPOLATION_CENTROID:
                 hlslStream << "    centroid ";
                 break;
+            case sh::INTERPOLATION_SAMPLE:
+                hlslStream << "    sample ";
+                break;
             default:
                 UNREACHABLE();
         }

src/libANGLE/renderer/vulkan/vk_caps_utils.cpp

@@ -272,7 +272,29 @@ void RendererVk::ensureCapsInitialized() const
     // VkPipelineMultisampleStateCreateInfo structure must be set to VK_FALSE and the
     // minSampleShading member is ignored. This also specifies whether shader modules can declare
     // the SampleRateShading capability
-    mNativeExtensions.sampleShadingOES = (mPhysicalDeviceFeatures.sampleRateShading == VK_TRUE);
+    bool supportSampleRateShading      = (mPhysicalDeviceFeatures.sampleRateShading == VK_TRUE);
+    mNativeExtensions.sampleShadingOES = supportSampleRateShading;
+
+    mNativeCaps.minInterpolationOffset          = limitsVk.minInterpolationOffset;
+    mNativeCaps.maxInterpolationOffset          = limitsVk.maxInterpolationOffset;
+    mNativeCaps.subPixelInterpolationOffsetBits = limitsVk.subPixelInterpolationOffsetBits;
+
+    // From the Vulkan spec:
+    //
+    // > The values minInterpolationOffset and maxInterpolationOffset describe the closed interval
+    // > of supported interpolation offsets : [ minInterpolationOffset, maxInterpolationOffset ].
+    // > The ULP is determined by subPixelInterpolationOffsetBits. If
+    // > subPixelInterpolationOffsetBits is 4, this provides increments of(1 / 2^4) = 0.0625, and
+    // > thus the range of supported interpolation offsets would be[-0.5, 0.4375]
+    //
+    // OES_shader_multisample_interpolation requires a maximum value of -0.5 for
+    // MIN_FRAGMENT_INTERPOLATION_OFFSET_OES and minimum 0.5 for
+    // MAX_FRAGMENT_INTERPOLATION_OFFSET_OES.  Vulkan has an identical limit for
+    // minInterpolationOffset, but it's limit for maxInterpolationOffset is 0.5-(1/ULP).
+    // OES_shader_multisample_interpolation is therefore only supported if
+    // maxInterpolationOffset is at least 0.5.
+    mNativeExtensions.multisampleInterpolationOES =
+        supportSampleRateShading && (mNativeCaps.maxInterpolationOffset >= 0.5);
 
     // https://vulkan.lunarg.com/doc/view/1.0.30.0/linux/vkspec.chunked/ch31s02.html
     mNativeCaps.maxElementIndex  = std::numeric_limits<GLuint>::max() - 1;

src/tests/deqp_support/deqp_gles31_test_expectations.txt

@@ -187,6 +187,12 @@
 // Cannot create 2D (array) view of 3D texture.
 3886 VULKAN : dEQP-GLES31.functional.image_load_store.3d.*layer = FAIL
 
+// Conflict between "interpolateAtOffset()" and the viewport transformation for a default framebuffer
+3589 VULKAN : dEQP-GLES31.functional.shaders.multisample_interpolation.interpolate_at_offset.no_qualifiers.default_framebuffer = FAIL
+3589 VULKAN : dEQP-GLES31.functional.shaders.multisample_interpolation.interpolate_at_offset.centroid_qualifier.default_framebuffer = FAIL
+3589 VULKAN : dEQP-GLES31.functional.shaders.multisample_interpolation.interpolate_at_offset.sample_qualifier.default_framebuffer = FAIL
+3589 VULKAN : dEQP-GLES31.functional.shaders.multisample_interpolation.interpolate_at_offset.array_element.default_framebuffer = FAIL
+
 ////
 //// Android (i.e. Pixel*) Vulkan expectations
 ////