Transform clips by the entity's transform (flutter#87)

Author: bdero

impeller/aiks/aiks_unittests.cc

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <array>
 #include "flutter/testing/testing.h"
 #include "impeller/aiks/aiks_playground.h"
 #include "impeller/aiks/canvas.h"
@@ -122,6 +123,26 @@ TEST_F(AiksTest, CanRenderNestedClips) {
   ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
 }
 
+TEST_F(AiksTest, ClipsUseCurrentTransform) {
+  std::array<Color, 5> colors = {Color::White(), Color::Black(),
+                                 Color::SkyBlue(), Color::Red(),
+                                 Color::Yellow()};
+  Canvas canvas;
+  Paint paint;
+
+  canvas.Translate(Vector3(300, 300));
+  for (int i = 0; i < 15; i++) {
+    canvas.Translate(-Vector3(300, 300));
+    canvas.Scale(Vector3(0.8, 0.8));
+    canvas.Translate(Vector3(300, 300));
+
+    paint.color = colors[i % colors.size()];
+    canvas.ClipPath(PathBuilder{}.AddCircle({0, 0}, 300).TakePath());
+    canvas.DrawRect(Rect(-300, -300, 600, 600), paint);
+  }
+  ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
+}
+
 TEST_F(AiksTest, CanSaveLayerStandalone) {
   Canvas canvas;
 

impeller/entity/contents/clip_contents.cc

@@ -35,7 +35,8 @@ bool ClipContents::Render(const ContentContext& renderer,
   VS::FrameInfo info;
   // The color really doesn't matter.
   info.color = Color::SkyBlue();
-  info.mvp = Matrix::MakeOrthographic(pass.GetRenderTargetSize());
+  info.mvp = Matrix::MakeOrthographic(pass.GetRenderTargetSize()) *
+             entity.GetTransformation();
 
   VS::BindFrameInfo(cmd, pass.GetTransientsBuffer().EmplaceUniform(info));