Vulkan Development

When to Use

Vulkan is a set of graphics APIs for 2D and 3D rendering. To start with, you need to create a VkSurfaceKHR instance, which works with the OHNativeWindow module to implement buffer recycling.

A VkSurfaceKHR instance is obtained through an OHNativeWindow, which is obtained from the <XComponent>. Therefore, the OHNativeWindow module must be used together with the XComponent and NativeWindow modules.

Available APIs

For details about the APIs, see Vulkan.

How to Develop

The following steps illustrate how to create a VkSurfaceKHR instance.

To use the extended APIs, define the macro VK_USE_PLATFORM_OHOS in the CMakeLists.txt file.

ADD_DEFINITIONS(-DVK_USE_PLATFORM_OHOS=1)

Adding Dynamic Link Libraries

Add the following libraries to CMakeLists.txt:

libace_ndk.z.so
libnative_window.so
libvulkan.so

Including Header Files

#include <ace/xcomponent/native_interface_xcomponent.h>
#include <native_window/external_window.h>
#include <vulkan/vulkan.h>

1. Create a Vulkan instance.

   VkInstance instance = VK_NULL_HANDLE;
   
   VkApplicationInfo appInfo = {};
   appInfo.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
   appInfo.pApplicationName = "vulkanExample";
   appInfo.pEngineName = "vulkanExample";
   appInfo.apiVersion = VK_API_VERSION_1_3;
   
   VkInstanceCreateInfo instanceCreateInfo = {};
   instanceCreateInfo.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
   instanceCreateInfo.pNext = NULL;
   instanceCreateInfo.pApplicationInfo = &appInfo;
   
   std::vector<const char *> instanceExtensions = {
       VK_KHR_SURFACE_EXTENSION_NAME,
       VK_OHOS_SURFACE_EXTENSION_NAME // Surface extension.
   };
   instanceCreateInfo.enabledExtensionCount = static_cast<uint32_t>(instanceExtensions.size());
   instanceCreateInfo.ppEnabledExtensionNames = instanceExtensions.data();
   
   vkCreateInstance(&instanceCreateInfo, nullptr, &instance);
   

2. Obtain an OHNativeWindow instance.

   The OHNativeWindow instance is obtained from the <XComponent>. For details about how to use the <XComponent>, see XComponent and XComponent Development.

   1. Add an <XComponent> to ets/pages/Index.ets.

      XComponent({
          id: 'xcomponentId',
          type: 'surface',
          libraryname: 'entry'
      })
      .margin({ bottom: 20 })
      .width(360)
      .height(360)
      

   2. Obtain an OHNativeWindow instance from the <XComponent>.

      // Callback function of the \<XComponent> triggered when a surface is created.
      void OnSurfaceCreatedCB(OH_NativeXComponent *component, void *window) {
          // You can obtain an OHNativeWindow instance from the callback function.
          OHNativeWindow *nativeWindow = static_cast<OHNativeWindow *>(window);
      }
      
      static napi_value Init(napi_env env, napi_value exports) {
          napi_property_descriptor desc[] = {{"add", nullptr, Add, nullptr, nullptr, nullptr, napi_default, nullptr}};
          napi_define_properties(env, exports, sizeof(desc) / sizeof(desc[0]), desc);
      
          napi_value exportInstance = nullptr;
          OH_NativeXComponent *nativeXComponent = nullptr;
          // Obtain a native XComponent.
          napi_get_named_property(env, exports, OH_NATIVE_XCOMPONENT_OBJ, &exportInstance);
          napi_unwrap(env, exportInstance, reinterpret_cast<void **>(&nativeXComponent));
          // Obtain the XComponent ID.
          char idStr[OH_XCOMPONENT_ID_LEN_MAX + 1] = {};
          uint64_t idSize = OH_XCOMPONENT_ID_LEN_MAX + 1;
          OH_NativeXComponent_GetXComponentId(nativeXComponent, idStr, &idSize);
      
          // Declare an XComponent callback.
          OH_NativeXComponent_Callback callback;
          // Register the OnSurfaceCreated callback function.
          callback.OnSurfaceCreated = OnSurfaceCreatedCB;
          // Register the callback function for the native XComponent.
          OH_NativeXComponent_RegisterCallback(nativeXComponent, &callback);
      
          return exports;
      }
      

3. Create a VkSurfaceKHR instance.

   VkSurfaceKHR surface = VK_NULL_HANDLE;
   VkSurfaceCreateInfoOHOS surfaceCreateInfo = {};
   surfaceCreateInfo.sType = VK_STRUCTURE_TYPE_SURFACE_CREATE_INFO_OHOS;
   surfaceCreateInfo.window = nativeWindow; // nativeWindow is obtained from the OnSurfaceCreatedCB callback function in the previous step.
   int err = vkCreateSurfaceOHOS(instance, &surfaceCreateInfo, NULL, &surface);
   if (err != VK_SUCCESS) {
       // Creating the surface failed.
   }
   

For details about how to use Vulkan, visit the Vulkan official website.