Check depth-stencil attachment sample count.

src/libANGLE/Framebuffer.cpp

@@ -1081,11 +1081,11 @@ int Framebuffer::getSamples(const Context *context)
     {
         // For a complete framebuffer, all attachments must have the same sample count.
         // In this case return the first nonzero sample size.
-        const auto *firstColorAttachment = mState.getFirstColorAttachment();
-        if (firstColorAttachment)
+        const auto *firstNonNullAttachment = mState.getFirstNonNullAttachment();
+        if (firstNonNullAttachment)
         {
-            ASSERT(firstColorAttachment->isAttached());
-            return firstColorAttachment->getSamples();
+            ASSERT(firstNonNullAttachment->isAttached());
+            return firstNonNullAttachment->getSamples();
         }
     }
 

src/libANGLE/State.cpp

@@ -1822,19 +1822,19 @@ void State::getIntegerv(const Context *context, GLenum pname, GLint *params)
             {
                 switch (pname)
                 {
-                  case GL_SAMPLE_BUFFERS:
-                      if (framebuffer->getSamples(context) != 0)
-                      {
-                          *params = 1;
-                    }
-                    else
-                    {
-                        *params = 0;
-                    }
-                    break;
-                  case GL_SAMPLES:
-                      *params = framebuffer->getSamples(context);
-                      break;
+                    case GL_SAMPLE_BUFFERS:
+                        if (framebuffer->getSamples(context) != 0)
+                        {
+                            *params = 1;
+                        }
+                        else
+                        {
+                            *params = 0;
+                        }
+                        break;
+                    case GL_SAMPLES:
+                        *params = framebuffer->getSamples(context);
+                        break;
                 }
             }
             else

src/tests/gl_tests/FramebufferTest.cpp

@@ -498,6 +498,25 @@ TEST_P(FramebufferTest_ES3, ColorAttachmentIndexOutOfBounds)
     EXPECT_GL_ERROR(GL_INVALID_OPERATION);
 }
 
+// Check that depth-only attachments report the correct number of samples.
+TEST_P(FramebufferTest_ES3, MultisampleDepthOnly)
+{
+    GLRenderbuffer renderbuffer;
+    glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
+    glRenderbufferStorageMultisample(GL_RENDERBUFFER, 2, GL_DEPTH_COMPONENT24, 32, 32);
+
+    GLFramebuffer framebuffer;
+    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
+    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, renderbuffer);
+    ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
+    EXPECT_GL_NO_ERROR();
+
+    GLint samples = 0;
+    glGetIntegerv(GL_SAMPLES, &samples);
+    EXPECT_GL_NO_ERROR();
+    EXPECT_GE(samples, 2);
+}
+
 ANGLE_INSTANTIATE_TEST(FramebufferTest_ES3, ES3_D3D11(), ES3_OPENGL(), ES3_OPENGLES());
 
 class FramebufferTest_ES31 : public ANGLETest