Fix offset, add tests

Author: bdero

impeller/aiks/aiks_unittests.cc

@@ -2174,5 +2174,52 @@ TEST_P(AiksTest, CanRenderDestructiveSaveLayer) {
   ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
 }
 
+TEST_P(AiksTest, CanRenderBackdropBlurInteractive) {
+  auto callback = [&](AiksContext& renderer, RenderTarget& render_target) {
+    auto [a, b] = IMPELLER_PLAYGROUND_LINE(Point(50, 50), Point(300, 200), 30,
+                                           Color::White(), Color::White());
+
+    Canvas canvas;
+    canvas.DrawCircle({100, 100}, 50, {.color = Color::CornflowerBlue()});
+    canvas.DrawCircle({300, 200}, 100, {.color = Color::GreenYellow()});
+    canvas.DrawCircle({140, 170}, 75, {.color = Color::DarkMagenta()});
+    canvas.DrawCircle({180, 120}, 100, {.color = Color::OrangeRed()});
+    canvas.ClipRRect(Rect::MakeLTRB(a.x, a.y, b.x, b.y), 20);
+    canvas.SaveLayer({.blend_mode = BlendMode::kSource}, std::nullopt,
+                     [](const FilterInput::Ref& input,
+                        const Matrix& effect_transform, bool is_subpass) {
+                       return FilterContents::MakeGaussianBlur(
+                           input, Sigma(20.0), Sigma(20.0),
+                           FilterContents::BlurStyle::kNormal,
+                           Entity::TileMode::kClamp, effect_transform);
+                     });
+    canvas.Restore();
+
+    return renderer.Render(canvas.EndRecordingAsPicture(), render_target);
+  };
+
+  ASSERT_TRUE(OpenPlaygroundHere(callback));
+}
+
+TEST_P(AiksTest, CanRenderBackdropBlur) {
+  Canvas canvas;
+  canvas.DrawCircle({100, 100}, 50, {.color = Color::CornflowerBlue()});
+  canvas.DrawCircle({300, 200}, 100, {.color = Color::GreenYellow()});
+  canvas.DrawCircle({140, 170}, 75, {.color = Color::DarkMagenta()});
+  canvas.DrawCircle({180, 120}, 100, {.color = Color::OrangeRed()});
+  canvas.ClipRRect(Rect::MakeLTRB(75, 50, 375, 275), 20);
+  canvas.SaveLayer({.blend_mode = BlendMode::kSource}, std::nullopt,
+                   [](const FilterInput::Ref& input,
+                      const Matrix& effect_transform, bool is_subpass) {
+                     return FilterContents::MakeGaussianBlur(
+                         input, Sigma(30.0), Sigma(30.0),
+                         FilterContents::BlurStyle::kNormal,
+                         Entity::TileMode::kClamp, effect_transform);
+                   });
+  canvas.Restore();
+
+  ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
+}
+
 }  // namespace testing
 }  // namespace impeller

impeller/entity/entity_pass.cc

@@ -481,6 +481,9 @@ EntityPass::EntityResult EntityPass::GetEntityForElement(
       return EntityPass::EntityResult::Failure();
     }
 
+    FML_LOG(ERROR) << "Origin: " << subpass_coverage->origin
+                   << " Size: " << subpass_coverage->size;
+
     // Stencil textures aren't shared between EntityPasses (as much of the
     // time they are transient).
     if (!subpass->OnRender(renderer,                  // renderer
@@ -688,13 +691,18 @@ bool EntityPass::OnRender(
     // Tell the backdrop contents which portion of the rendered output will
     // actually be used. The contents may optionally use this hint to avoid
     // unnecessary rendering work.
-    backdrop_filter_contents->SetCoverageHint(
-        stencil_coverage_stack.back().coverage);
+    if (!stencil_coverage_stack.empty() &&
+        stencil_coverage_stack.back().coverage.has_value()) {
+      auto coverage_hint = Rect(
+          stencil_coverage_stack.back().coverage->origin - global_pass_position,
+          stencil_coverage_stack.back().coverage->size);
+      backdrop_filter_contents->SetCoverageHint(coverage_hint);
+    }
 
     Entity backdrop_entity;
     backdrop_entity.SetContents(std::move(backdrop_filter_contents));
     backdrop_entity.SetTransformation(
-        Matrix::MakeTranslation(Vector3(local_pass_position)));
+        Matrix::MakeTranslation(Vector3(-local_pass_position)));
     backdrop_entity.SetStencilDepth(stencil_depth_floor);
 
     render_element(backdrop_entity);

impeller/golden_tests/golden_playground_test_mac.cc

@@ -23,6 +23,8 @@ static const std::vector<std::string> kSkipTests = {
     "impeller_Play_AiksTest_CanRenderRadialGradient_Vulkan",
     "impeller_Play_AiksTest_CanRenderRadialGradientManyColors_Metal",
     "impeller_Play_AiksTest_CanRenderRadialGradientManyColors_Vulkan",
+    "impeller_Play_AiksTest_CanRenderBackdropBlurInteractive_Metal",
+    "impeller_Play_AiksTest_CanRenderBackdropBlurInteractive_Vulkan",
     "impeller_Play_AiksTest_TextFrameSubpixelAlignment_Metal",
     "impeller_Play_AiksTest_TextFrameSubpixelAlignment_Vulkan",
     "impeller_Play_AiksTest_ColorWheel_Metal",