OpenRoyale/native/include/engine.h

// engine.h - interface for the Titan engine core (the reconstruction target inside libg.so).
//
// The JNI boundary (native/src/libg/jni/titan_jni.cpp) forwards lifecycle / input / GL-config calls
// into this interface. The real implementation is recovered from the stripped ARMv7 libg.so.
//
// 64-bit note: the Java side hands the engine a `jlong` handle in createGameMain(...) and
// locationChanged(...). Store native pointers in that jlong (NOT jint) - it is already 64-bit-wide,
// which is what makes this boundary arm64-safe. See analysis/JNI_MAP.md.
#pragma once

#include <jni.h>
#include <cstdint>
#include <string>

namespace titan {

// Pixel/surface configuration the Java GLSurfaceView queries before creating the EGL context.
struct SurfaceConfig {
    int surfaceFormat = 4;   // getSurfaceFormat()  (RGBA_8888-ish; placeholder)
    int depthBits     = 16;  // getDepthBits()
    int stencilBits   = 8;   // getStencilBits()
    int allowedRotations = 0;// getAllowedScreenRotations()
};

class Engine {
public:
    static Engine& instance();

    // Called from JNI_OnLoad; caches the JavaVM for engine->Java up-calls.
    void onJniLoad(JavaVM* vm);

    // --- lifecycle (GameApp native methods) ---
    // createGameMain(AssetManager, docPath, ..., handle, w, h, ...): boots the engine and returns a
    // status/config string. Returns "" from the stub. `handle` is the 64-bit native handle carrier.
    std::string createGameMain(JNIEnv* env, jobject assetManager,
                               const std::string& docPath, const std::string& a2,
                               const std::string& a3, jlong handle,
                               int w, int h, int i2, int i3);
    bool init(int w, int h, const std::string& path);
    void start(const std::string& arg);
    void stop();
    void deinit();
    bool update();               // per-frame tick

    // --- input ---
    void setTouch(int id, int action, int x, int y);
    void clearTouches();

    // --- GL surface config queries ---
    SurfaceConfig surfaceConfig() const;

private:
    Engine() = default;
    JavaVM* vm_ = nullptr;
    bool booted_ = false;
};

} // namespace titan

// Exposed to the JNI layer (defined in titan_jni.cpp): the cached JavaVM.
extern "C" JavaVM* titan_get_vm();