feat(native): add Windows ARM64 support (#443)

Add a windowsarm64 target to generateLibs using the LLVM-MinGW clang
wrappers, with a shared createWindowsTarget() helper keeping the
existing x86_64 path intact.

LLVM-MinGW builds against libc++, which does not pull <exception>
transitively, so patch imgui-node-editor's crude_json.cpp through the
existing vendor patch flow.

Bundle the LWJGL natives-windows-arm64 classifiers in imgui-app and
document the direct Gradle build path.

Co-authored-by: DeepSeek <noreply@deepseek.com>

Author: Enaium

README.md

@@ -421,6 +421,15 @@ If you don't need FreeType or want a stock build under the project tree, call `g
 - Build: `./gradlew imgui-binding:generateLibs -Denvs=windows -Dlocal`
 - Run example: `./gradlew example:run -PlibPath="../imgui-binding/build/libsNative/windows64"`
 
+### Windows ARM64
+
+- Required on PATH: Ant, [LLVM-MinGW](https://github.com/mstorsjo/llvm-mingw) (the `aarch64-w64-mingw32-*`
+  wrappers).
+- Build: `./gradlew imgui-binding:generateLibs -Denvs=windowsarm64 -Dlocal`
+- Output: `imgui-binding/build/libsNative/windowsarm64/imgui-java64.dll`
+- Run example: `./gradlew example:run -PlibPath="../imgui-binding/build/libsNative/windowsarm64"`
+- The direct Gradle path builds without FreeType by default, matching the other platforms.
+
 ### Linux
 
 - Install dependencies: `mingw-w64-gcc`, `ant`. (Package names vary by distro.)
@@ -439,7 +448,7 @@ If you don't need FreeType or want a stock build under the project tree, call `g
 
 | Flag              | Effect                                                                                                                        |
 |-------------------|-------------------------------------------------------------------------------------------------------------------------------|
-| `-Denvs=<csv>`    | Target platforms — any of `windows`, `linux`, `macos`, `macosarm64`                                                           |
+| `-Denvs=<csv>`    | Target platforms — any of `windows`, `windowsarm64`, `linux`, `linuxarm64`, `macos`, `macosarm64`                             |
 | `-Dlocal`         | Output to `imgui-binding/build/libsNative/` instead of `/tmp/imgui/`                                                          |
 | `-Dfreetype=true` | Compile FreeType statically into the binary (requires `vendor_freetype.sh` to have been run; `build.sh` handles this for you) |
 

buildSrc/scripts/apply_vendor_patches.sh

@@ -30,3 +30,9 @@ apply_patch_idempotent() {
 apply_patch_idempotent \
     "$(pwd)/patches/imgui-node-editor-imgui-1.92-operator-star.patch" \
     include/imgui-node-editor
+
+# LLVM-MinGW's libc++ does not transitively include <exception>, so the
+# Windows ARM64 build needs the explicit include for std::terminate().
+apply_patch_idempotent \
+    "$(pwd)/patches/imgui-node-editor-libcxx-exception.patch" \
+    include/imgui-node-editor

buildSrc/src/main/groovy/tool/generator/GenerateLibs.groovy

@@ -31,6 +31,7 @@ class GenerateLibs extends DefaultTask {
 
     private final String[] buildEnvs = System.getProperty('envs')?.split(',')
     private final boolean forWindows = buildEnvs?.contains('windows')
+    private final boolean forWindowsArm64 = buildEnvs?.contains('windowsarm64')
     private final boolean forLinux = buildEnvs?.contains('linux')
     private final boolean forLinuxArm64 = buildEnvs?.contains('linuxarm64')
     private final boolean forMac = buildEnvs?.contains('macos')
@@ -114,10 +115,11 @@ class GenerateLibs extends DefaultTask {
         BuildTarget[] buildTargets = []
 
         if (forWindows) {
-            def win64 = BuildTarget.newDefaultTarget(Os.Windows, Architecture.Bitness._64)
-            requireCpp17(win64)
-            addFreeTypeIfEnabled(win64)
-            buildTargets += win64
+            buildTargets += createWindowsTarget(Architecture.x86)
+        }
+
+        if (forWindowsArm64) {
+            buildTargets += createWindowsTarget(Architecture.ARM)
         }
 
         if (forLinux) {
@@ -145,6 +147,8 @@ class GenerateLibs extends DefaultTask {
 
         if (forWindows)
             BuildExecutor.executeAnt(jniDir + '/build-windows64.xml', commonParams)
+        if (forWindowsArm64)
+            BuildExecutor.executeAnt(jniDir + '/build-windowsarm64.xml', commonParams)
         if (forLinux)
             BuildExecutor.executeAnt(jniDir + '/build-linux64.xml', commonParams)
         if (forLinuxArm64)
@@ -158,6 +162,8 @@ class GenerateLibs extends DefaultTask {
 
         if (forWindows)
             checkLibExist("windows64/imgui-java64.dll")
+        if (forWindowsArm64)
+            checkLibExist("windowsarm64/imgui-java64.dll")
         if (forLinux)
             checkLibExist("linux64/libimgui-java64.so")
         if (forLinuxArm64)
@@ -191,6 +197,20 @@ class GenerateLibs extends DefaultTask {
         return linuxTarget
     }
 
+    BuildTarget createWindowsTarget(Architecture arch) {
+        def windowsTarget = BuildTarget.newDefaultTarget(Os.Windows, Architecture.Bitness._64, arch)
+        windowsTarget.libName = "imgui-java64.dll" // Lib for arm64 will be named the same for consistency.
+        if (arch == Architecture.ARM) {
+            // Windows on ARM needs an LLVM/Clang based MinGW toolchain; GCC does not ship a
+            // Windows ARM64 target. LLVM-MinGW provides the aarch64-w64-mingw32- wrappers.
+            windowsTarget.cCompiler = "clang"
+            windowsTarget.cppCompiler = "clang++"
+        }
+        requireCpp17(windowsTarget)
+        addFreeTypeIfEnabled(windowsTarget)
+        return windowsTarget
+    }
+
     BuildTarget createMacTarget(Architecture arch) {
         def minMacOsVersion = '10.15'
         def macTarget = BuildTarget.newDefaultTarget(Os.MacOsX, Architecture.Bitness._64, arch)

imgui-app/build.gradle

@@ -24,7 +24,7 @@ dependencies {
     api 'org.lwjgl:lwjgl-opengl'
     api 'org.lwjgl:lwjgl-sdl'
 
-    ['natives-linux', 'natives-windows', 'natives-macos', 'natives-macos-arm64'].each {
+    ['natives-linux', 'natives-windows', 'natives-windows-arm64', 'natives-macos', 'natives-macos-arm64'].each {
         api "org.lwjgl:lwjgl::$it"
         api "org.lwjgl:lwjgl-glfw::$it"
         api "org.lwjgl:lwjgl-opengl::$it"

patches/imgui-node-editor-libcxx-exception.patch

@@ -0,0 +1,10 @@
+--- a/crude_json.cpp
++++ b/crude_json.cpp
+@@ -6,6 +6,7 @@
+ // CREDITS
+ //   Written by Michal Cichon
+ # include "crude_json.h"
++# include <exception>
+ # include <iomanip>
+ # include <limits>
+ # include <cstdlib>