disabled mipmap generation for vulkan

Author: gaaclarke

impeller/aiks/aiks_unittests.cc

@@ -3819,8 +3819,13 @@ TEST_P(AiksTest, GaussianBlurMipMapNestedLayer) {
         std::max(it->texture->GetTextureDescriptor().mip_count, max_mip_count);
   }
   EXPECT_EQ(max_mip_count, blur_required_mip_count);
-  EXPECT_EQ(log_capture.str().find(GaussianBlurFilterContents::kNoMipsError),
-            std::string::npos);
+  if (GetParam() == PlaygroundBackend::kMetal) {
+    EXPECT_EQ(log_capture.str().find(GaussianBlurFilterContents::kNoMipsError),
+              std::string::npos);
+  } else {
+    EXPECT_NE(log_capture.str().find(GaussianBlurFilterContents::kNoMipsError),
+              std::string::npos);
+  }
 }
 
 TEST_P(AiksTest, GaussianBlurMipMapImageFilter) {
@@ -3847,8 +3852,13 @@ TEST_P(AiksTest, GaussianBlurMipMapImageFilter) {
         std::max(it->texture->GetTextureDescriptor().mip_count, max_mip_count);
   }
   EXPECT_EQ(max_mip_count, blur_required_mip_count);
-  EXPECT_EQ(log_capture.str().find(GaussianBlurFilterContents::kNoMipsError),
-            std::string::npos);
+  if (GetParam() == PlaygroundBackend::kMetal) {
+    EXPECT_EQ(log_capture.str().find(GaussianBlurFilterContents::kNoMipsError),
+              std::string::npos);
+  } else {
+    EXPECT_NE(log_capture.str().find(GaussianBlurFilterContents::kNoMipsError),
+              std::string::npos);
+  }
 }
 
 }  // namespace testing

impeller/entity/entity_pass.cc

@@ -256,6 +256,12 @@ static EntityPassTarget CreateRenderTarget(ContentContext& renderer,
   /// What's important is the `StorageMode` of the textures, which cannot be
   /// changed for the lifetime of the textures.
 
+  if (context->GetBackendType() != Context::BackendType::kMetal) {
+    // TODO(tbd): Implement mip map generation on vulkan.
+    // TODO(tbd): Implement mip map generation on opengles.
+    mip_count = 1;
+  }
+
   RenderTarget target;
   if (context->GetCapabilities()->SupportsOffscreenMSAA()) {
     target = RenderTarget::CreateOffscreenMSAA(