Wire up asset resolution.

engine/src/flutter/impeller/host/BUILD.gn

@@ -4,12 +4,17 @@
 
 import("//flutter/common/config.gni")
 import("//flutter/impeller/tools/metal/metal_library.gni")
+import("//flutter/testing/testing.gni")
 
 metal_library("impeller_host_shaders") {
   name = "impeller_host"
   sources = [ "shaders.metal" ]
 }
 
+test_fixtures("impeller_host_fixtures") {
+  fixtures = [ "assets/ColorMap.png" ]
+}
+
 executable("host") {
   cflags_objc = flutter_cflags_objc_arc
   cflags_objcc = flutter_cflags_objcc_arc
@@ -20,6 +25,8 @@ executable("host") {
 
   sources = [
     "ShaderTypes.h",
+    "assets_location.cc",
+    "assets_location.h",
     "impeller_host_view_controller.h",
     "impeller_host_view_controller.mm",
     "impeller_renderer.h",
@@ -38,6 +45,7 @@ executable("host") {
   ]
 
   deps = [
+    ":impeller_host_fixtures",
     ":impeller_host_shaders",
     "//flutter/fml",
     "//flutter/impeller/impeller",

engine/src/flutter/impeller/host/assets_location.cc

@@ -0,0 +1,31 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/impeller/host/assets_location.h"
+
+#include "flutter/fml/paths.h"
+
+namespace flutter::testing {
+
+//------------------------------------------------------------------------------
+/// @brief      Returns the directory containing the test fixture for the target
+///             if this target has fixtures configured. If there are no
+///             fixtures, this is a link error. If you see a linker error on
+///             this symbol, the unit-test target needs to depend on a
+///             `test_fixtures` target.
+///
+/// @return     The fixtures path.
+///
+const char* GetFixturesPath();
+
+}  // namespace flutter::testing
+
+namespace impeller {
+
+std::string GetAssetLocation(const char* asset_path) {
+  return fml::paths::JoinPaths(
+      {flutter::testing::GetFixturesPath(), std::string{asset_path}});
+}
+
+}  // namespace impeller

engine/src/flutter/impeller/host/assets_location.h

@@ -0,0 +1,11 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <string>
+
+namespace impeller {
+
+std::string GetAssetLocation(const char* asset_path);
+
+}  // namespace  impeller

engine/src/flutter/impeller/host/impeller_renderer.mm

@@ -5,6 +5,7 @@
 #import <ModelIO/ModelIO.h>
 #import <simd/simd.h>
 
+#import "assets_location.h"
 #include "flutter/fml/logging.h"
 #import "impeller_renderer.h"
 #import "shaders_location.h"
@@ -178,9 +179,11 @@ static const size_t kAlignedUniformsSize = (sizeof(Uniforms) & ~0xFF) + 0x100;
     MTKTextureLoaderOptionTextureStorageMode : @(MTLStorageModePrivate)
   };
 
-  _colorMap = [textureLoader newTextureWithName:@"ColorMap"
-                                    scaleFactor:1.0
-                                         bundle:nil
+  auto color_map_data = [NSData
+      dataWithContentsOfFile:@(impeller::GetAssetLocation("ColorMap.png")
+                                   .c_str())];
+
+  _colorMap = [textureLoader newTextureWithData:color_map_data
                                         options:textureLoaderOptions
                                           error:&error];