ES31: Support struct arrays as Geometry Shader inputs

src/compiler/translator/ParseContext.cpp

@@ -1054,8 +1054,13 @@ bool TParseContext::checkIsValidTypeAndQualifierForArray(const TSourceLoc &index
     // In ESSL1.00 shaders, structs cannot be varying (section 4.3.5). This is checked elsewhere.
     // In ESSL3.00 shaders, struct inputs/outputs are allowed but not arrays of structs (section
     // 4.3.4).
+    // Geometry shader requires each user-defined input be declared as arrays or inside input
+    // blocks declared as arrays (GL_EXT_geometry_shader section 11.1gs.4.3). For the purposes of
+    // interface matching, such variables and blocks are treated as though they were not declared
+    // as arrays (GL_EXT_geometry_shader section 7.4.1).
     if (mShaderVersion >= 300 && elementType.getBasicType() == EbtStruct &&
-        sh::IsVarying(elementType.qualifier))
+        sh::IsVarying(elementType.qualifier) &&
+        !IsGeometryShaderInput(mShaderType, elementType.qualifier))
     {
         error(indexLocation, "cannot declare arrays of structs of this qualifier",
               TType(elementType).getCompleteString().c_str());

src/tests/compiler_tests/GeometryShader_test.cpp

@@ -1571,3 +1571,55 @@ TEST_F(GeometryShaderOutputCodeTest, ValidateGLInMembersInOutputShaderString)
     compile(shaderString2);
     EXPECT_TRUE(foundInESSLCode("].gl_Position"));
 }
+
+// Verify that geometry shader inputs can be declared as struct arrays.
+TEST_F(GeometryShaderTest, StructArrayInput)
+{
+    const std::string &shaderString =
+        R"(#version 310 es
+        #extension GL_EXT_geometry_shader : require
+        layout (points) in;
+        layout (points, max_vertices = 2) out;
+        struct S
+        {
+            float value1;
+            vec4 value2;
+        };
+        in S gs_input[];
+        out S gs_output;
+        void main()
+        {
+            gs_output = gs_input[0];
+        })";
+
+    if (!compile(shaderString))
+    {
+        FAIL() << "Shader compilation failed, expecting success:\n" << mInfoLog;
+    }
+}
+
+// Verify that geometry shader outputs cannot be declared as struct arrays.
+TEST_F(GeometryShaderTest, StructArrayOutput)
+{
+    const std::string &shaderString =
+        R"(#version 310 es
+        #extension GL_EXT_geometry_shader : require
+        layout (points) in;
+        layout (points, max_vertices = 2) out;
+        struct S
+        {
+            float value1;
+            vec4 value2;
+        };
+        out S gs_output[1];
+        void main()
+        {
+            gs_output[0].value1 = 1.0;
+            gs_output[0].value2 = vec4(1.0, 0.0, 0.0, 1.0);
+        })";
+
+    if (compile(shaderString))
+    {
+        FAIL() << "Shader compilation succeeded, expecting failure:\n" << mInfoLog;
+    }
+}
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