From 15efb79d10f449fa98bd1dc7323b09af9331e449 Mon Sep 17 00:00:00 2001
From: Brandon DeRosier <bdero@google.com>
Date: Wed, 6 Apr 2022 21:46:03 -0700
Subject: [PATCH] Ignore the stencil in the imgui pipeline (flutter/engine#120)

---
 .../impeller/playground/imgui/imgui_impl_impeller.cc       | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/engine/src/flutter/impeller/playground/imgui/imgui_impl_impeller.cc b/engine/src/flutter/impeller/playground/imgui/imgui_impl_impeller.cc
index 682ee9bb381..b42696c4dc6 100644
--- a/engine/src/flutter/impeller/playground/imgui/imgui_impl_impeller.cc
+++ b/engine/src/flutter/impeller/playground/imgui/imgui_impl_impeller.cc
@@ -89,6 +89,13 @@ bool ImGui_ImplImpeller_Init(std::shared_ptr<impeller::Context> context) {
                                           impeller::ImguiRasterFragmentShader>::
         MakeDefaultPipelineDescriptor(*context);
     desc->SetSampleCount(impeller::SampleCount::kCount4);
+    auto stencil = desc->GetFrontStencilAttachmentDescriptor();
+    if (stencil.has_value()) {
+      stencil->stencil_compare = impeller::CompareFunction::kAlways;
+      stencil->depth_stencil_pass = impeller::StencilOperation::kKeep;
+      desc->SetStencilAttachmentDescriptors(stencil.value());
+    }
+
     bd->pipeline =
         context->GetPipelineLibrary()->GetRenderPipeline(std::move(desc)).get();
     IM_ASSERT(bd->pipeline != nullptr && "Could not create ImGui pipeline.");