Disallow glReadPixels with multi-view read framebuffers

extensions/ANGLE_multiview.txt

@@ -161,7 +161,7 @@ Additions to Chapter 4 of the OpenGL ES 3.0 Specification
     Add to the end of the section:
 
     "   ReadPixels generates an INVALID_FRAMEBUFFER_OPERATION error if
-    the multi-view layout of the current read buffer is not NONE."
+    the multi-view layout of the current read framebuffer is not NONE."
 
     Modify section 4.3.3 (Copying pixels), p. 198
 

src/libANGLE/validationES.cpp

@@ -5456,6 +5456,16 @@ bool ValidateReadPixelsBase(Context *context,
         return false;
     }
 
+    // ANGLE_multiview, Revision 1:
+    // ReadPixels generates an INVALID_FRAMEBUFFER_OPERATION error if the multi-view layout of the
+    // current read framebuffer is not NONE.
+    if (readBuffer->getMultiviewLayout() != GL_NONE)
+    {
+        context->handleError(InvalidFramebufferOperation()
+                             << "Attempting to read from a multi-view framebuffer.");
+        return false;
+    }
+
     if (context->getExtensions().webglCompatibility)
     {
         // The ES 2.0 spec states that the format must be "among those defined in table 3.4,

src/tests/gl_tests/FramebufferMultiviewTest.cpp

@@ -458,4 +458,27 @@ TEST_P(FramebufferMultiviewTest, InvalidBlit)
     }
 }
 
+// Test that glReadPixels generates an invalid framebuffer operation error if the current read
+// framebuffer has a multi-view layout.
+TEST_P(FramebufferMultiviewTest, InvalidReadPixels)
+{
+    if (!requestMultiviewExtension())
+    {
+        return;
+    }
+
+    mTexture2D = CreateTexture2D(GL_RGBA8, GL_RGBA, GL_UNSIGNED_BYTE);
+    ASSERT_GL_NO_ERROR();
+
+    const GLint viewportOffsets[2] = {0};
+    glFramebufferTextureMultiviewSideBySideANGLE(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, mTexture2D,
+                                                 0, 1, &viewportOffsets[0]);
+    ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
+    ASSERT_GL_NO_ERROR();
+
+    GLColor pixelColor;
+    glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &pixelColor.R);
+    EXPECT_GL_ERROR(GL_INVALID_FRAMEBUFFER_OPERATION);
+}
+
 ANGLE_INSTANTIATE_TEST(FramebufferMultiviewTest, ES3_OPENGL());
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