Nazi Zombies: Portable FTEQW for Android

The engine behind the Android port, and the changes that got it onto a phone.

Upstream is nzp-team/fteqw, NZ:P's fork of Spike's FTEQW. FTEQW has had an Android backend for years, but nothing was driving it: no modern build, no touch input, no way to reach the servers.

This branch is what closed that gap. It is a fork rather than a patch file because engine work needs history. A ten-thousand-line diff regenerated after every edit has no blame, nothing to bisect, and no way to offer a single fix upstream.

Used by nzportable-android, which is where the game code, the data and the APK live.

What this fork changes

Area	Change
Build	CMake wiring for an arm64 build driven by Gradle and a current NDK, instead of the dead make droid path
Vulkan	Ask for an IDENTITY pre-transform where the surface allows it
Audio	Output through the low-latency AudioTrack path
Input	Touchscreen, controller and system keys plumbed through the Android glue
Images	stb_image vendored, so the PNG menu artwork decodes
Network	ICE always takes the DTLS server role
Network	GnuTLS wired in for the TLS and DTLS the ICE broker requires

Android panels report a rotated currentTransform, and using it as the pre-transform without rotating the rendering to match leaves the image sideways. Asking for IDENTITY makes the compositor present it upright instead. The SUBOPTIMAL result that follows is expected rather than a problem, so it counts as success. Treating it as a failure rebuilt the swapchain every single frame.

The DTLS change is what lets an Android client join a Windows host. FTE's SChannel backend cannot act as a DTLS server, and the roles are negotiated separately from who is hosting the game, so the Android side always offers a=setup:passive and forces the peer to be the client.

Touch input also brought two fixes that are not Android-specific. The dispatcher had no case for ACTION_CANCEL, so pointers taken away by a system gesture were never released and stayed held down. Separately, two use-after-frees were found by running under ARM memory tagging, one in the Vulkan sampler teardown and one in the download handler, both of which had gone unnoticed because a freed block usually still holds the value being read.

Building

Not built on its own. It is compiled as part of the Android app, which drives CMake and the NDK through Gradle. See nzportable-android.

The build config is engine/common/config_nzportable.h, which is where RTLIGHTS is switched on.

Upstream's other platforms are untouched and should still build the way they always did, though nothing here tests them.

Licence

GPL-2.0, the same as FTEQW, see LICENSE. engine/libs/stb_image.h and stb_image_write.h are public domain.