Files
cup_edit/windows/include/filament/backend/PresentCallable.h

105 lines
3.9 KiB
C++

/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
//! \file
#ifndef TNT_FILAMENT_BACKEND_PRESENTCALLABLE
#define TNT_FILAMENT_BACKEND_PRESENTCALLABLE
#include <utils/compiler.h>
namespace filament {
namespace backend {
/**
* A PresentCallable is a callable object that, when called, schedules a frame for presentation on
* a SwapChain.
*
* Typically, Filament's backend is responsible scheduling a frame's presentation. However, there
* are certain cases where the application might want to control when a frame is scheduled for
* presentation.
*
* For example, on iOS, UIKit elements can be synchronized to 3D content by scheduling a present
* within a CATransation:
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* void myFrameScheduledCallback(PresentCallable presentCallable, void* user) {
* [CATransaction begin];
* // Update other UI elements...
* presentCallable();
* [CATransaction commit];
* }
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* To obtain a PresentCallable, set a SwapChain::FrameScheduledCallback on a SwapChain with the
* SwapChain::setFrameScheduledCallback method. The callback is called with a PresentCallable object
* and optional user data:
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* swapChain->setFrameScheduledCallback(myFrameScheduledCallback, nullptr);
* if (renderer->beginFrame(swapChain)) {
* renderer->render(view);
* renderer->endFrame();
* }
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* @remark Only Filament's Metal backend supports PresentCallables and frame callbacks. Other
* backends ignore the callback (which will never be called) and proceed normally.
*
* @remark The SwapChain::FrameScheduledCallback is called on an arbitrary thread.
*
* Applications *must* call each PresentCallable they receive. Each PresentCallable represents a
* frame that is waiting to be presented. If an application fails to call a PresentCallable, a
* memory leak could occur. To "cancel" the presentation of a frame, pass false to the
* PresentCallable, which will cancel the presentation of the frame and release associated memory.
*
* @see Renderer, SwapChain::setFrameScheduledCallback
*/
class UTILS_PUBLIC PresentCallable {
public:
using PresentFn = void(*)(bool presentFrame, void* user);
PresentCallable(PresentFn fn, void* user) noexcept;
~PresentCallable() noexcept = default;
PresentCallable(const PresentCallable& rhs) = default;
PresentCallable& operator=(const PresentCallable& rhs) = default;
/**
* Call this PresentCallable, scheduling the associated frame for presentation. Pass false for
* presentFrame to effectively "cancel" the presentation of the frame.
*
* @param presentFrame if false, will not present the frame but releases associated memory
*/
void operator()(bool presentFrame = true) noexcept;
private:
PresentFn mPresentFn;
void* mUser = nullptr;
};
/**
* @deprecated, FrameFinishedCallback has been renamed to SwapChain::FrameScheduledCallback.
*/
using FrameFinishedCallback UTILS_DEPRECATED = void(*)(PresentCallable callable, void* user);
} // namespace backend
} // namespace filament
#endif // TNT_FILAMENT_BACKEND_PRESENTCALLABLE