Disallow active transform feedback with a multi-view draw framebuffer

src/libANGLE/validationES.cpp

@@ -2821,13 +2821,25 @@ bool ValidateDrawBase(ValidationContext *context, GLenum mode, GLsizei count)
 
     if (context->getExtensions().multiview)
     {
-        const int programNumViews = program->getNumViews();
-        if (programNumViews != -1 && framebuffer->getNumViews() != programNumViews)
+        const int programNumViews     = program->getNumViews();
+        const int framebufferNumViews = framebuffer->getNumViews();
+        if (programNumViews != -1 && framebufferNumViews != programNumViews)
         {
             context->handleError(InvalidOperation() << "The number of views in the active program "
                                                        "and draw framebuffer does not match.");
             return false;
         }
+
+        const TransformFeedback *transformFeedbackObject = state.getCurrentTransformFeedback();
+        if (transformFeedbackObject != nullptr && transformFeedbackObject->isActive() &&
+            framebufferNumViews > 1)
+        {
+            context->handleError(InvalidOperation()
+                                 << "There is an active transform feedback object "
+                                    "when the number of views in the active draw "
+                                    "framebuffer is greater than 1.");
+            return false;
+        }
     }
 
     // Uniform buffer validation

src/tests/gl_tests/MultiviewDrawTest.cpp

@@ -234,4 +234,59 @@ TEST_P(MultiviewDrawValidationTest, NumViewsMismatch)
     }
 }
 
+// The test verifies that glDraw*:
+// 1) generates an INVALID_OPERATION error if the number of views in the active draw framebuffer is
+// greater than 1 and there is an active transform feedback object.
+// 2) does not generate any error if the number of views in the draw framebuffer is 1.
+TEST_P(MultiviewDrawValidationTest, ActiveTransformFeedback)
+{
+    if (!requestMultiviewExtension())
+    {
+        return;
+    }
+
+    const GLint viewportOffsets[4] = {0, 0, 2, 0};
+
+    const std::string &vsSource =
+        "#version 300 es\n"
+        "void main()\n"
+        "{}\n";
+    const std::string &fsSource =
+        "#version 300 es\n"
+        "precision mediump float;\n"
+        "void main()\n"
+        "{}\n";
+    ANGLE_GL_PROGRAM(program, vsSource, fsSource);
+    glUseProgram(program);
+
+    GLBuffer tbo;
+    glBindBuffer(GL_TRANSFORM_FEEDBACK_BUFFER, tbo);
+    glBufferData(GL_TRANSFORM_FEEDBACK_BUFFER, sizeof(float) * 4u, nullptr, GL_STATIC_DRAW);
+
+    GLTransformFeedback transformFeedback;
+    glBindTransformFeedback(GL_TRANSFORM_FEEDBACK, transformFeedback);
+    glBeginTransformFeedback(GL_TRIANGLES);
+    ASSERT_GL_NO_ERROR();
+
+    // Check that drawArrays generates an error when there is an active transform feedback object
+    // and the number of views in the draw framebuffer is greater than 1.
+    {
+        glFramebufferTextureMultiviewSideBySideANGLE(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, mTex2d,
+                                                     0, 2, &viewportOffsets[0]);
+        glDrawArrays(GL_TRIANGLES, 0, 3);
+        EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    }
+
+    // Check that drawArrays does not generate an error when the number of views in the draw
+    // framebuffer is 1.
+    {
+        glFramebufferTextureMultiviewSideBySideANGLE(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, mTex2d,
+                                                     0, 1, &viewportOffsets[0]);
+        glDrawArrays(GL_TRIANGLES, 0, 3);
+        EXPECT_GL_NO_ERROR();
+    }
+
+    glEndTransformFeedback();
+}
+
 ANGLE_INSTANTIATE_TEST(MultiviewDrawValidationTest, ES31_OPENGL());
\ No newline at end of file

src/tests/test_utils/gl_raii.h

@@ -44,12 +44,13 @@ class GLWrapper
     GLuint mHandle = 0;
 };
 
-using GLVertexArray  = GLWrapper<glGenVertexArrays, glDeleteVertexArrays>;
-using GLBuffer       = GLWrapper<glGenBuffers, glDeleteBuffers>;
-using GLTexture      = GLWrapper<glGenTextures, glDeleteTextures>;
-using GLFramebuffer  = GLWrapper<glGenFramebuffers, glDeleteFramebuffers>;
-using GLRenderbuffer = GLWrapper<glGenRenderbuffers, glDeleteRenderbuffers>;
-using GLSampler      = GLWrapper<glGenSamplers, glDeleteSamplers>;
+using GLVertexArray       = GLWrapper<glGenVertexArrays, glDeleteVertexArrays>;
+using GLBuffer            = GLWrapper<glGenBuffers, glDeleteBuffers>;
+using GLTexture           = GLWrapper<glGenTextures, glDeleteTextures>;
+using GLFramebuffer       = GLWrapper<glGenFramebuffers, glDeleteFramebuffers>;
+using GLRenderbuffer      = GLWrapper<glGenRenderbuffers, glDeleteRenderbuffers>;
+using GLSampler           = GLWrapper<glGenSamplers, glDeleteSamplers>;
+using GLTransformFeedback = GLWrapper<glGenTransformFeedbacks, glDeleteTransformFeedbacks>;
 
 // Don't use GLProgram directly, use ANGLE_GL_PROGRAM.
 namespace priv