add support for desktop examples on MacOS (Apple Silicon M1=arm64/ x86_64/ i386)

.bazelrc

@@ -83,10 +83,16 @@ build:ios_fat --config=ios
 build:ios_fat --ios_multi_cpus=armv7,arm64
 build:ios_fat --watchos_cpus=armv7k
 
+# MacOS configs.
 build:darwin_x86_64 --apple_platform_type=macos
 build:darwin_x86_64 --macos_minimum_os=10.12
 build:darwin_x86_64 --cpu=darwin_x86_64
 
+# MacOS Big Sur with Apple Silicon M1
+build:darwin_arm64 --apple_platform_type=macos
+build:darwin_arm64 --macos_minimum_os=10.16
+build:darwin_arm64 --cpu=darwin_arm64
+
 # This bazelrc file is meant to be written by a setup script.
 try-import %workspace%/.configure.bazelrc
 

README.md

@@ -77,6 +77,113 @@ The source code is hosted in the
 run code search using
 [Google Open Source Code Search](https://cs.opensource.google/mediapipe/mediapipe).
 
+### Build on MacOS
+
+#### Prepare
+1. install bazel/opencv/ffmpeg:
+```bash
+brew install bazel
+brew install opencv@3
+brew install ffmpeg
+```
+
+2. Set .bazelversion:
+Run 
+```bash
+brew list bazel
+```
+to get bazel version, which may print: 
+```
+/opt/homebrew/Cellar/bazel/4.1.0/bin/bazel
+/opt/homebrew/Cellar/bazel/4.1.0/bin/bazel-4.1.0
+/opt/homebrew/Cellar/bazel/4.1.0/etc/bash_completion.d/bazel-complete.bash
+/opt/homebrew/Cellar/bazel/4.1.0/libexec/bin/ (3 files)
+/opt/homebrew/Cellar/bazel/4.1.0/share/zsh/site-functions/_bazel```
+```
+
+Update .bazelversion:
+```bash
+echo 4.1.0 > .bazelversion
+```
+
+1. Set the right paths to opencv/ffmpeg in WORKSPACE (line 212~222), for example:
+```
+new_local_repository(
+    name = "macos_opencv",
+    build_file = "@//third_party:opencv_macos.BUILD",
+    path = "/opt/homebrew/Cellar/opencv@3/3.4.14_3",
+)
+
+new_local_repository(
+    name = "macos_ffmpeg",
+    build_file = "@//third_party:ffmpeg_macos.BUILD",
+    path = "/opt/homebrew/Cellar/ffmpeg/4.4_2",
+)
+```
+
+#### CPU: Apple Silicon M1
+1. Build "hello_world":
+```bash
+bazel build -c opt --define MEDIAPIPE_DISABLE_GPU=1 --cpu darwin_arm64 mediapipe/examples/desktop/hello_world:hello_world
+```
+and run:
+```bash
+export GLOG_logtostderr=1
+bazel-bin/mediapipe/examples/desktop/hello_world/hello_world
+```
+2. Build all available examples under mediapipe/examples/desktop:
+```bash
+bash build_macos_desktop_examples.sh --cpu m1 -b
+```
+
+3. Build and run one example app (e.g. mediapipe/examples/desktop/face_detection):
+```
+bash build_macos_desktop_examples.sh --cpu m1 --app face_detection -r
+```
+
+#### CPU: x86_64
+1. Build "hello_world":
+```bash
+bazel build -c opt --define MEDIAPIPE_DISABLE_GPU=1 --cpu darwin_x86_64 mediapipe/examples/desktop/hello_world:hello_world
+```
+and run:
+```bash
+export GLOG_logtostderr=1
+bazel-bin/mediapipe/examples/desktop/hello_world/hello_world
+```
+
+2. Build all available examples under mediapipe/examples/desktop:
+```bash
+bash build_macos_desktop_examples.sh --cpu x86_64 -b
+```
+
+3. Build and run one example app (e.g. mediapipe/examples/desktop/face_detection):
+```
+bash build_macos_desktop_examples.sh --cpu x86_64 --app face_detection -r
+```
+
+#### CPU: i386
+1. Build "hello_world":
+```bash
+bazel build -c opt --define MEDIAPIPE_DISABLE_GPU=1 --cpu darwin_i386 mediapipe/examples/desktop/hello_world:hello_world
+```
+
+and run:
+```bash
+export GLOG_logtostderr=1
+bazel-bin/mediapipe/examples/desktop/hello_world/hello_world
+```
+
+2. Build all available examples under mediapipe/examples/desktop:
+```bash
+bash build_macos_desktop_examples.sh --cpu i386 -b
+```
+
+3. Build and run one example app (e.g. mediapipe/examples/desktop/face_detection):
+```
+bash build_macos_desktop_examples.sh --cpu i386 --app face_detection -r
+```
+
 ## Publications
 
 *   [Bringing artworks to life with AR](https://developers.googleblog.com/2021/07/bringing-artworks-to-life-with-ar.html)

WORKSPACE

@@ -1,5 +1,17 @@
 workspace(name = "mediapipe")
 
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+http_archive(
+    name = "bazel_skylib",
+    urls = [
+        "https://github.com/bazelbuild/bazel-skylib/releases/download/1.0.3/bazel-skylib-1.0.3.tar.gz",
+        "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.0.3/bazel-skylib-1.0.3.tar.gz",
+    ],
+    sha256 = "1c531376ac7e5a180e0237938a2536de0c54d93f5c278634818e0efc952dd56c",
+)
+load("@bazel_skylib//:workspace.bzl", "bazel_skylib_workspace")
+bazel_skylib_workspace()
+
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 http_archive(

build_macos_desktop_examples.sh

@@ -0,0 +1,149 @@
+#!/bin/bash
+# Copyright 2020 The MediaPipe Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# =========================================================================
+#
+# Script to build/run all MediaPipe desktop example apps (with webcam input).
+#
+# CPU options: [arm64/m1/M1, x86_64, i386]
+# To only build "face_detection" app and store it in out_dir for MacOS with M1 CPU:
+#   $ ./build_desktop_examples.sh -c m1 -d out_dir -a face_detection
+#   Omitting -d and the associated directory saves all generated apps in the
+#   current directory.
+# To build and run all apps and store them in out_dir for MacOS with M1 CPU:
+#   $ ./build_desktop_examples.sh -c m1 -d out_dir
+#   Omitting -d and the associated directory saves all generated apps in the
+#   current directory.
+# To build all apps and store them in out_dir for MacOS with x86_64 CPU:
+#   $ ./build_desktop_examples.sh -c x86_64 -d out_dir -b
+#   Omitting -d and the associated directory saves all generated apps in the
+#   current directory.
+# To run all apps already stored in out_dir:
+#   $ ./build_desktop_examples.sh -d out_dir -r
+#   Omitting -d and the associated directory assumes all apps are in the current
+#   directory.
+
+set -e
+
+out_dir="."
+build_only=false
+run_only=false
+# cpu options: [arm64/m1/M1, x86_64, i386]
+# corresponding bazel cpu options: [darwin_arm64, darwin_x86_64, darwin]
+cpu="arm64"
+app_dir="mediapipe/examples/desktop"
+app_name=""
+bin_dir="bazel-bin"
+
+while [[ -n $1 ]]; do
+  case $1 in
+    -d)
+      shift
+      out_dir=$1
+      ;;
+    -c | --cpu)
+      shift
+      cpu=$1
+      ;;
+    -a | --app)
+      shift
+      app_name=$1
+      ;;
+    -b)
+      build_only=true
+      ;;
+    -r)
+      run_only=true
+      ;;
+    *)
+      echo "Unsupported input argument $1."
+      exit 1
+      ;;
+  esac
+  shift
+done
+
+case $cpu in
+    x86_64 | i386)
+      cpu="darwin_$cpu"
+      ;;
+    arm64 | m1 | M1)
+      cpu="darwin_arm64"
+      ;;
+    *)
+      echo "Unsupported cpu argument $1."
+      exit 1
+      ;;
+  esac
+
+echo "app_dir: $app_dir"
+echo "out_dir: $out_dir"
+echo "cpu: $cpu"
+echo "app_name: $app_name"
+
+declare -a default_bazel_flags=(build -c opt --define MEDIAPIPE_DISABLE_GPU=1 --cpu $cpu)
+declare -a bazel_flags
+
+if [[ ! -z "${app_name}" ]]; then
+  echo "Only build app: ${app_dir}/${app_name}"
+  declare -a apps=("${app_dir}/${app_name}")
+else
+  echo "Build all available apps under $app_dir"
+  apps="${app_dir}/*"
+fi
+
+for app in ${apps}; do
+  if [[ -d "${app}" ]]; then
+    target_name=${app##*/}
+    if [[ "${target_name}" == "autoflip" ||
+          "${target_name}" == "hello_world" ||
+          "${target_name}" == "media_sequence" ||
+          "${target_name}" == "object_detection_3d" ||
+          "${target_name}" == "template_matching" ||
+          "${target_name}" == "youtube8m" ]]; then
+      echo "Skip ${target_name}"
+      continue
+    fi
+    target="${app}:${target_name}_cpu"
+
+    echo "=== Target: ${target}"
+
+    if [[ $run_only == false ]]; then
+      bazel_flags=("${default_bazel_flags[@]}")
+      bazel_flags+=(${target})
+
+      bazel "${bazel_flags[@]}"
+      cp -f "${bin_dir}/${app}/"*"_cpu" "${out_dir}"
+    fi
+    if [[ $build_only == false ]]; then
+      if  [[ ${target_name} == "object_tracking" ]]; then
+        graph_name="tracking/object_detection_tracking"
+      elif [[ ${target_name} == "upper_body_pose_tracking" ]]; then
+        graph_name="pose_tracking/upper_body_pose_tracking"
+      else
+        graph_name="${target_name}/${target_name}"
+      fi
+      if [[ ${target_name} == "holistic_tracking" ||
+            ${target_name} == "iris_tracking" ||
+            ${target_name} == "pose_tracking" ||
+            ${target_name} == "upper_body_pose_tracking" ]]; then
+        graph_suffix="cpu"
+      else
+        graph_suffix="desktop_live"
+      fi
+      GLOG_logtostderr=1 "${out_dir}/${target_name}_cpu" \
+        --calculator_graph_config_file=mediapipe/graphs/"${graph_name}_${graph_suffix}.pbtxt"
+    fi
+  fi
+done

mediapipe/BUILD

@@ -75,7 +75,8 @@ alias(
     actual = select({
         ":macos_i386": ":macos_i386",
         ":macos_x86_64": ":macos_x86_64",
-        "//conditions:default": ":macos_i386",  # Arbitrarily chosen from above.
+        ":macos_arm64": ":macos_arm64",
+        "//conditions:default": ":macos_x86_64",  # Arbitrarily chosen from above.
     }),
     visibility = ["//visibility:public"],
 )
@@ -119,6 +120,15 @@ config_setting(
     visibility = ["//visibility:public"],
 )
 
+config_setting(
+    name = "macos_arm64",
+    values = {
+        "apple_platform_type": "macos",
+        "cpu": "darwin_arm64",
+    },
+    visibility = ["//visibility:public"],
+)
+
 [
     config_setting(
         name = arch,