fix: don't start the app from main() on android; use the real inset retry

main() must not run real_main on android. The library's DT_INIT points at Odin's
_odin_entry_point, which the loader runs the moment NativeActivity dlopens
libmain.so -- before the glue calls android_main, so context.user_ptr is nil and
backend_init faults writing app.onAppCmd. The proc still has to exist: package
main requires it and it is the desktop entry point.

The insets retry now uses request_render_at. A plain request_render made before
the build is consumed by the frame it is running in, so it schedules nothing and
the loop parks with insets unresolved; it only appeared to work because the
first frames redraw anyway while the tree settles.

Guards the JNI-only paths (show_toast, refresh_insets) behind the android
subtarget so the shared real_main is usable on desktop. refresh_insets returns
true there rather than false: zero insets are correct where there are no system
bars, and returning false would retry every frame forever.

Also declares appCategory=game, and enables the engine's frame timings.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
2026-09-07 20:30:45 +02:00
co-authored by Claude Opus 5
parent 238ab73f0f
commit 5776c4924d
2 changed files with 50 additions and 14 deletions
+2 -1
View File
@@ -13,10 +13,11 @@
<application
android:label="Dogfooding"
android:appCategory="game"
android:hasCode="false"
android:icon="@mipmap/ic_launcher"
android:roundIcon="@mipmap/ic_launcher_round"
android:debuggable="false">
android:debuggable="true">
<activity android:name="android.app.NativeActivity"
android:configChanges="orientation|keyboardHidden"
+40 -5
View File
@@ -2,6 +2,7 @@ package main
import "shared:android"
import "base:runtime"
import "core:time"
import engine "shared:zephr"
import "jni"
@@ -18,7 +19,18 @@ insets: Edge_Insets
insets_valid: bool
main :: proc() {
// Android must not start the app from here. This library's DT_INIT points at
// Odin's _odin_entry_point, which the dynamic loader runs the moment
// NativeActivity dlopens libmain.so -- long before the glue spawns its
// thread and calls android_main, and so before context.user_ptr holds the
// android_app. Running real_main here reaches backend_init with a nil app
// and faults writing app.onAppCmd.
//
// The proc still has to exist: package main requires it, and it is the
// desktop entry point.
when ODIN_PLATFORM_SUBTARGET != .Android {
real_main()
}
}
real_main :: proc() {
@@ -41,6 +53,11 @@ real_main :: proc() {
// flat out forever, which on a phone is straight battery burn.
engine.set_render_on_change(true)
// Rolling work-vs-swap timings to logcat, to tell a slow frame apart from a
// frame that is merely waiting on vsync.
engine.set_frame_stats(true)
for !engine.should_quit() {
engine.frame_start()
defer engine.frame_end()
@@ -60,11 +77,16 @@ real_main :: proc() {
if !insets_valid {
insets_valid = refresh_insets()
if !insets_valid {
// The decor view attaches asynchronously and produces no event
// when it does. Under render_on_change the loop would park
// before the retry ever ran, leaving the app bar with no status
// bar padding.
engine.request_render()
// The decor view attaches asynchronously and emits no event when
// it does, so the retry has to drive itself.
//
// Deliberately request_render_at, not request_render: a plain
// request made here -- before the build -- is consumed by the
// very frame it is running in, so it schedules nothing and the
// loop parks with insets still unresolved. A timed wake is the
// one that survives into the next frame. It only works today
// because the first frames redraw anyway while the tree settles.
engine.request_render_at(engine.get_time() + 16 * time.Millisecond)
}
}
@@ -105,6 +127,10 @@ draw_ui :: proc() {
// Toast needs a Java looper on this thread. Preparing one is a one-time cost
// and the native ALooper the engine polls is unaffected -- they're separate.
show_toast :: proc(msg: string) {
// The bindings all fail closed without a VM, so this would be harmless off
// Android -- just a pointless chain of JNI calls on every tap. Compile it
// out instead of relying on that.
when ODIN_PLATFORM_SUBTARGET == .Android {
if l, ok := looper_my_looper(); ok && l == nil {
looper_prepare()
}
@@ -114,11 +140,20 @@ show_toast :: proc(msg: string) {
return
}
toast_show(toast)
}
}
// Walks Activity -> Window -> decor View -> WindowInsets. Returns false while
// the decor view is still unattached, which is normal for the first few frames.
refresh_insets :: proc() -> bool {
// Returning true, not false: zero insets are the correct answer where there
// are no system bars, and the caller retries every frame until this succeeds
// -- requesting a render each time. Failing here would pin the desktop loop
// awake forever, which is exactly what render_on_change is meant to avoid.
when ODIN_PLATFORM_SUBTARGET != .Android {
return true
}
// This runs every frame until it succeeds, and each call below returns a
// local ref. Without a frame to scope them the ref table fills and aborts.
env := jni.env()