Allow Linux users to build Android even if Python 2 is their default Python

After this commit, users who have the `python` executable as Python 2 can do simply:

    cd android/
    ./build-all.py
    ./build.py

Previously, the following would fail:

    python3 build-all.py

since build-all.py did subcalls to `python build.py`.

Remove install-all.py as it is redundant with `build-all.py -deploy`,
instead of fixing it as well.

Introduce argparse since we are separating argument parsing out of
the `main()` function.

Tested in Ubuntu 16.04, behaviour should be unchanged for Windows.

android/README.md

@@ -39,7 +39,7 @@ This will build all apks and puts them into the **bin** folder.
 #### Build and deploy
 
 ```
-install-all.py
+build-all.py -deploy
 ```
 
 This will build all apks and deploys them to the currently attached android device.

android/build-all.py

@@ -1,8 +1,11 @@
-# Build all examples
-# Pass -deploy to also install on connected device
+#!/usr/bin/env python3
+
+import argparse
 import subprocess
 import sys
 
+import build
+
 EXAMPLES = [
     "bloom",
     "computecullandlod",
@@ -64,18 +67,16 @@ COLOR_END = '\033[0m'
 
 CURR_INDEX = 0
 
-BUILD_ARGUMENTS = ""
-for arg in sys.argv[1:]:
-    if arg == "-deploy":
-        BUILD_ARGUMENTS += "-deploy"
-    if arg == "-validation":
-        BUILD_ARGUMENTS += "-validation"
+parser = argparse.ArgumentParser()
+parser.add_argument('-deploy', default=False, action='store_true', help="install examples on device")
+parser.add_argument('-validation', default=False, action='store_true')
+args = parser.parse_args()
 
 print("Building all examples...")
 
 for example in EXAMPLES:
     print(COLOR_GREEN + "Building %s (%d/%d)" % (example, CURR_INDEX, len(EXAMPLES)) + COLOR_END)
-    if subprocess.call(("python build.py %s %s" % (example, BUILD_ARGUMENTS)).split(' ')) != 0:
+    if not build.main(example, args.deploy, args.validation):
         print("Error during build process for %s" % example)
         sys.exit(-1)
     CURR_INDEX += 1

android/build.py

@@ -1,94 +1,86 @@
-# Single example build and deploy script
+#!/usr/bin/env python3
+
 import os
 import subprocess
 import sys
 import shutil
 import glob
 import json
+import argparse
 
-# Android SDK version used
-SDK_VERSION = "android-23"
+def main(project_folder, deploy=False, validation=False):
 
-PROJECT_FOLDER = ""
+    # Android SDK version used
+    SDK_VERSION = "android-23"
 
-# Check if python 3, python 2 not supported
-if sys.version_info <= (3, 0):
+    # Check if python 3, python 2 not supported
+    if sys.version_info <= (3, 0):
         print("Sorry, requires Python 3.x, not Python 2.x")
-    sys.exit(-1)
+        return False
 
-# Name/folder of the project to build
-if len(sys.argv) > 1:
-    PROJECT_FOLDER = sys.argv[1]
-if not os.path.exists(PROJECT_FOLDER):
-    print("Please specify a valid project folder to build!")
-    sys.exit(-1)
+    # Definitions (apk name, folders, etc.) will be taken from a json definition
+    if not os.path.isfile(os.path.join(project_folder, "example.json")):
+        print("Could not find json definition for example %s" % project_folder)
+        return False
 
-# Definitions (apk name, folders, etc.) will be taken from a json definition
-if not os.path.isfile(os.path.join(PROJECT_FOLDER, "example.json")):
-    print("Could not find json definition for example %s" % PROJECT_FOLDER)
-    sys.exit(-1)
-
-# Check if a build file is present, if not create one using the android SDK version specified
-if not os.path.isfile(os.path.join(PROJECT_FOLDER, "build.xml")):
+    # Check if a build file is present, if not create one using the android SDK version specified
+    if not os.path.isfile(os.path.join(project_folder, "build.xml")):
         print("Build.xml not present, generating with %s " % SDK_VERSION)
         ANDROID_CMD = "android"
         if os.name == 'nt':
             ANDROID_CMD += ".bat"
-    if subprocess.call(("%s update project -p ./%s -t %s" % (ANDROID_CMD, PROJECT_FOLDER, SDK_VERSION)).split(' ')) != 0:
+        if subprocess.call(("%s update project -p ./%s -t %s" % (ANDROID_CMD, project_folder, SDK_VERSION)).split(' ')) != 0:
             print("Error: Project update failed!")
-        sys.exit(-1)
+            return False
 
-# Load example definition from json file
-with open(os.path.join(PROJECT_FOLDER, "example.json")) as json_file:
+    # Load example definition from json file
+    with open(os.path.join(project_folder, "example.json")) as json_file:
         EXAMPLE_JSON = json.load(json_file)
 
-APK_NAME = EXAMPLE_JSON["apkname"]
-SHADER_DIR = EXAMPLE_JSON["directories"]["shaders"]
+    APK_NAME = EXAMPLE_JSON["apkname"]
+    SHADER_DIR = EXAMPLE_JSON["directories"]["shaders"]
 
-# Additional
-ADDITIONAL_DIRS = []
-ADDITIONAL_FILES = []
-if "assets" in EXAMPLE_JSON and "additional" in EXAMPLE_JSON["assets"]:
+    # Additional
+    ADDITIONAL_DIRS = []
+    ADDITIONAL_FILES = []
+    if "assets" in EXAMPLE_JSON and "additional" in EXAMPLE_JSON["assets"]:
         ADDITIONAL = EXAMPLE_JSON["assets"]["additional"]
         if "directories" in ADDITIONAL:
             ADDITIONAL_DIRS = ADDITIONAL["directories"]
         if "files" in ADDITIONAL:
             ADDITIONAL_FILES = ADDITIONAL["files"]
 
-# Get assets to be copied
-ASSETS_MODELS = []
-ASSETS_TEXTURES = []
-if "assets" in EXAMPLE_JSON:
+    # Get assets to be copied
+    ASSETS_MODELS = []
+    ASSETS_TEXTURES = []
+    if "assets" in EXAMPLE_JSON:
         ASSETS = EXAMPLE_JSON["assets"]
         if "models" in ASSETS:
             ASSETS_MODELS = EXAMPLE_JSON["assets"]["models"]
         if "textures" in ASSETS:
             ASSETS_TEXTURES = EXAMPLE_JSON["assets"]["textures"]
 
-# Enable validation
-VALIDATION = False
-BUILD_ARGS = ""
+    # Enable validation
+    BUILD_ARGS = ""
 
-for arg in sys.argv[1:]:
-    if arg == "-validation":
-        VALIDATION = True
+    if validation:
         # Use a define to force validation in code
         BUILD_ARGS = "APP_CFLAGS=-D_VALIDATION"
-        break
 
-# Verify submodules are loaded in external folder
-if not os.listdir("../external/glm/") or not os.listdir("../external/gli/"):
+    # Verify submodules are loaded in external folder
+    if not os.listdir("../external/glm/") or not os.listdir("../external/gli/"):
         print("External submodules not loaded. Clone them using:")
         print("\tgit submodule init\n\tgit submodule update")
-    sys.exit(-1)
+        return False
 
-# Build
-os.chdir(PROJECT_FOLDER)
+    # Build
+    old_cwd = os.getcwd()
+    os.chdir(project_folder)
 
-if subprocess.call("ndk-build %s" %BUILD_ARGS, shell=True) == 0:
+    if subprocess.call("ndk-build %s" %BUILD_ARGS, shell=True) == 0:
         print("Build successful")
 
-    if VALIDATION:
+        if validation:
             # Copy validation layers
             # todo: Currently only arm v7
             print("Validation enabled, copying validation layers...")
@@ -125,18 +117,37 @@ if subprocess.call("ndk-build %s" %BUILD_ARGS, shell=True) == 0:
         shutil.copy("../../android/images/icon.png", "./res/drawable")
 
         if subprocess.call("ant debug -Dout.final.file=%s.apk" % APK_NAME, shell=True) == 0:
-        # Deploy to device
-        for arg in sys.argv[1:]:
-            if arg == "-deploy":
-                if subprocess.call("adb install -r %s.apk" % APK_NAME, shell=True) != 0:
+            if deploy and subprocess.call("adb install -r %s.apk" % APK_NAME, shell=True) != 0:
                 print("Could not deploy to device!")
         else:
             print("Error during build process!")
-        sys.exit(-1)
-else:
+            return False
+    else:
         print("Error building project!")
-    sys.exit(-1)
+        return False
 
-# Copy apk to bin folder
-os.makedirs("../bin", exist_ok=True)
-shutil.move('%s.apk' % APK_NAME, "../bin/%s.apk" % APK_NAME)
+    # Copy apk to bin folder
+    os.makedirs("../bin", exist_ok=True)
+    shutil.move('%s.apk' % APK_NAME, "../bin/%s.apk" % APK_NAME)
+    os.chdir(old_cwd)
+    return True
+
+class ReadableDir(argparse.Action):
+    def __call__(self, parser, namespace, values, option_string=None):
+        if not os.path.isdir(values):
+            raise argparse.ArgumentTypeError("{0} is not a valid path".format(values))
+        if not os.access(values, os.R_OK):
+            raise argparse.ArgumentTypeError("{0} is not a readable dir".format(values))
+        setattr(namespace, self.dest,values)
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description="Build and deploy a single example")
+    parser.add_argument('-deploy', default=False, action='store_true', help="install example on device")
+    parser.add_argument('-validation', default=False, action='store_true')
+    parser.add_argument('project_folder', action=ReadableDir)
+    try:
+        args = parser.parse_args()
+    except SystemExit:
+        sys.exit(1)
+    ok = main(args.project_folder, args.deploy, args.validation)
+    sys.exit(0 if ok else 1)

android/install-all.py

@@ -1,13 +0,0 @@
-# Install all examples to connected device(s)
-import subprocess
-import sys
-
-answer = input("Install all vulkan examples to attached device, this may take some time! (Y/N)").lower() == 'y'
-if answer:
-    BUILD_ARGUMENTS = ""
-    for arg in sys.argv[1:]:
-        if arg == "-validation":
-            BUILD_ARGUMENTS += "-validation"
-    if subprocess.call(("python build-all.py -deploy %s" % BUILD_ARGUMENTS).split(' ')) != 0:
-        print("Error: Not all examples may have been installed!")
-        sys.exit(-1)

android/uninstall-all.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 # Remove all examples from connected device(s)
 import subprocess
 import sys

download_assets.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 import sys
 from urllib.request import urlretrieve
 from zipfile import ZipFile