android - 我是否必须创建一个 native Activity 来获取窗口，或者我可以从 Android 设备上的窗口管理器为 vulkan 应用程序提供一个？

Question

无论我在 Internet 上找到什么资源，从创建 native Activity 并提供 android_app->window 来创建 vkAndroidSurfaceKHR 进行初始化。所以，我只想知道我们能否有一个窗口管理器来提供这个窗口来创建表面。

Answer 1

要从简单的 Java 应用程序创建 vkAndroidSurfaceKHR，您需要获取 android.view.View 的实例并执行对 ANativeWindow_fromSurface(env, win) 的 native 调用。注意 View 及其子类能够从 GPU 绘制 3D 内容，如 OpenGL 和 Vulkan。

我在 api 中就是这样做的9100行左右，

 /**
 * Get display handles for Android and AWT Canvas
 * @param win - a java.awt.Canvas instance or a android.view.Surface
 * @param displayHandles - return native surface handle
 * 
 * @return true if all goes Ok.
 */
protected static native boolean getDisplayHandles0(Object win, long[] displayHandles);/*

 #ifdef VK_USE_PLATFORM_ANDROID_KHR 
   ANativeWindow* window;       
   // Return the ANativeWindow associated with a Java Surface object,
   // for interacting with it through native code.  This acquires a reference
   // on the ANativeWindow that is returned; be sure to use ANativeWindow_release()
   // when done with it so that it doesn't leak.
   window = ANativeWindow_fromSurface(env, win);
   displayHandles[0] = reinterpret_cast<jlong>(window);
   return JNI_TRUE;
 #else  
 ...
 #endif
*/
}

我还以另一种方式实现了这一点，大约在第 10370 行，来源相同:

/**
 * 
 * @see http://www.javaworld.com/article/2075263/core-java/embed-java-code-into-your-native-apps.html
 * 
 * @param instance - Vulkan instance 
 * @param nativeWindow - instance of android.view.Surface or java.awt.Canvas
 * @param pAllocatorHandle - native handle to a VkAllocationCallbacks
 * @param pSurface
 * @return
 */
protected static native int vkCreateWindowSurface0(long instance, 
                                                   Object nativeWindow, 
                                                   long pAllocatorHandle, 
                                                   long[] pSurface,
                                                   long[] awtDrawingSurface);/*

VkAllocationCallbacks* pAllocator = reinterpret_cast<VkAllocationCallbacks*>(pAllocatorHandle);
VkInstance vkInstance = reinterpret_cast<VkInstance>(instance);
VkSurfaceKHR* _pSurface = new VkSurfaceKHR[1];
VkResult res = VkResult::VK_ERROR_NATIVE_WINDOW_IN_USE_KHR;

#ifdef VK_USE_PLATFORM_ANDROID_KHR       
    ANativeWindow* window = NULL;  
    window = ANativeWindow_fromSurface(env, nativeWindow);
    if (window == NULL) 
         return VkResult::VK_ERROR_NATIVE_WINDOW_IN_USE_KHR;

    VkAndroidSurfaceCreateInfoKHR info;
     info.sType = VkStructureType::VK_STRUCTURE_TYPE_ANDROID_SURFACE_CREATE_INFO_KHR;
     info.pNext = NULL;
     info.flags = 0;
     info.window = window; 
     res =  vkCreateAndroidSurfaceKHR(vkInstance, &info, pAllocator, _pSurface);
 #else 
 ...
 #endif

 if(res >= 0){
   pSurface[0] = reinterpret_cast<jlong>(_pSurface[0]);           
}else{
   pSurface[0] = (jlong)0;
   fprintf(stderr,"Failed to create Vulkan SurfaceKHR.");
}

 delete[] _pSurface;         
 return res;
 }