Add automatic ANGLE downloads

.gitignore

@@ -26,3 +26,4 @@ sdk/orca_surface.c
 .vscode/settings.json
 
 __pycache__
+scripts/files

scripts/build_runtime.py

@@ -1,7 +1,11 @@
 import argparse
+import glob
 import os
 import platform
+import urllib.request
+import shutil
 import subprocess
+from zipfile import ZipFile
 
 import checksum
 from log import *
@@ -173,4 +177,40 @@ def ensure_angle():
             exit(1)
 
     if not angle_exists:
-        pass
+        download_angle()
+
+
+def download_angle():
+    print("Downloading ANGLE...")
+    if platform.system() == "Windows":
+        build = "win"
+        checksumkey = "angle.zip-win"
+        extension = "dll"
+    elif platform.system() == "Darwin":
+        extension = "dylib"
+        build = "macos-12"
+        checksumkey = "angle.zip-mac"
+
+        # TODO(ben): make universal dylibs
+        if platform.machine() == "arm64":
+            log_error(f"automated ANGLE builds are not yet available for Apple silicon")
+            return
+    else:
+        log_error(f"could not automatically download ANGLE for unknown platform {platform.system()}")
+        return
+
+    url = f"https://github.com/HandmadeNetwork/build-angle/releases/download/{ANGLE_VERSION}/angle-{build}-{ANGLE_VERSION}.zip"
+    with urllib.request.urlopen(url) as response:
+        os.makedirs("scripts/files", exist_ok=True)
+        with open("scripts/files/angle.zip", "wb") as out:
+            shutil.copyfileobj(response, out)
+
+    if not checksum.checkfile(checksumkey, "scripts/files/angle.zip"):
+        log_error(f"ANGLE download did not match checksum")
+        exit(1)
+
+    with ZipFile("scripts/files/angle.zip", "r") as anglezip:
+        anglezip.extractall(path="scripts/files")
+
+    for filepath in glob.glob(f"scripts/files/angle/bin/*.{extension}"):
+        shutil.copy(filepath, "milepost/lib")

scripts/checksums.json

@@ -1,6 +1,8 @@
 {
+    "angle.zip-win": "pizza",
+    "angle.zip-mac-x64": "a3422c456278ff037ef89a7808e0ba256d972d4832d5272fc3d4aa4f7912c1e0",
     "libEGL-win": "3c8b22317664650deba704dd40bbd56447c579ee3a3de18a9c114449a883a36d",
     "libGLESv2-win": "a10e0ce850a981b11d3d0f01a7efbf8ce46ac74e5fa763b5c43a80c4238da389",
-    "libEGL-mac-arm64": "227445d896047207d1dcef91a8182d886692bc470f402033a6f0831eacb82592",
-    "libGLESv2-mac-arm64": "c814948060494796cda4a3febd8652e1bbf0787a69c2f7e9afd41fc666dc91fe"
+    "libEGL-mac": "227445d896047207d1dcef91a8182d886692bc470f402033a6f0831eacb82592",
+    "libGLESv2-mac": "c814948060494796cda4a3febd8652e1bbf0787a69c2f7e9afd41fc666dc91fe"
 }