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/*
* Copyright 2013 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.
*/
#ifndef ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
#define ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
#include "BufferQueueInterposer.h"
#include "DisplaySurface.h"
// ---------------------------------------------------------------------------
namespace android {
// ---------------------------------------------------------------------------
class HWComposer;
/* This DisplaySurface implementation uses a BufferQueueInterposer to pass
* partially- or fully-composited buffers from the OpenGL ES driver to
* HWComposer to use as the output buffer for virtual displays. Allowing HWC
* to compose into the same buffer that contains GLES results saves bandwidth
* compared to having two separate BufferQueues for frames with at least some
* GLES composition.
*
* The alternative would be to have two complete BufferQueues, one from GLES
* to HWC and one from HWC to the virtual display sink (e.g. video encoder).
* For GLES-only frames, the same bandwidth saving could be achieved if buffers
* could be acquired from the GLES->HWC queue and inserted into the HWC->sink
* queue. That would be complicated and doesn't help the mixed GLES+HWC case.
*
* On frames with no GLES composition, the VirtualDisplaySurface dequeues a
* buffer directly from the sink IGraphicBufferProducer and passes it to HWC,
* bypassing the GLES driver. This is only guaranteed to work if
* eglSwapBuffers doesn't immediately dequeue a buffer for the next frame,
* since we can't rely on being able to dequeue more than one buffer at a time.
*
* TODO(jessehall): Add a libgui test that ensures that EGL/GLES do lazy
* dequeBuffers; we've wanted to require that for other reasons anyway.
*/
class VirtualDisplaySurface : public DisplaySurface {
public:
VirtualDisplaySurface(HWComposer& hwc, int disp,
const sp<IGraphicBufferProducer>& sink,
const String8& name);
virtual sp<IGraphicBufferProducer> getIGraphicBufferProducer() const;
virtual status_t compositionComplete();
virtual status_t advanceFrame();
virtual void onFrameCommitted(int fenceFd);
virtual void dump(String8& result) const;
private:
virtual ~VirtualDisplaySurface();
// immutable after construction
HWComposer& mHwc;
int mDisplayId;
sp<BufferQueueInterposer> mSource;
String8 mName;
// mutable, must be synchronized with mMutex
Mutex mMutex;
sp<GraphicBuffer> mAcquiredBuffer;
};
// ---------------------------------------------------------------------------
} // namespace android
// ---------------------------------------------------------------------------
#endif // ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
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