VirtualDisplaySurface.h revision 13f01cbdbd34779a234bc674df79e23672fd5c0b
1/* 2 * Copyright 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#ifndef ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H 18#define ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H 19 20#include "BufferQueueInterposer.h" 21#include "DisplaySurface.h" 22 23// --------------------------------------------------------------------------- 24namespace android { 25// --------------------------------------------------------------------------- 26 27class HWComposer; 28 29/* This DisplaySurface implementation uses a BufferQueueInterposer to pass 30 * partially- or fully-composited buffers from the OpenGL ES driver to 31 * HWComposer to use as the output buffer for virtual displays. Allowing HWC 32 * to compose into the same buffer that contains GLES results saves bandwidth 33 * compared to having two separate BufferQueues for frames with at least some 34 * GLES composition. 35 * 36 * The alternative would be to have two complete BufferQueues, one from GLES 37 * to HWC and one from HWC to the virtual display sink (e.g. video encoder). 38 * For GLES-only frames, the same bandwidth saving could be achieved if buffers 39 * could be acquired from the GLES->HWC queue and inserted into the HWC->sink 40 * queue. That would be complicated and doesn't help the mixed GLES+HWC case. 41 * 42 * On frames with no GLES composition, the VirtualDisplaySurface dequeues a 43 * buffer directly from the sink IGraphicBufferProducer and passes it to HWC, 44 * bypassing the GLES driver. This is only guaranteed to work if 45 * eglSwapBuffers doesn't immediately dequeue a buffer for the next frame, 46 * since we can't rely on being able to dequeue more than one buffer at a time. 47 * 48 * TODO(jessehall): Add a libgui test that ensures that EGL/GLES do lazy 49 * dequeBuffers; we've wanted to require that for other reasons anyway. 50 */ 51class VirtualDisplaySurface : public DisplaySurface { 52public: 53 VirtualDisplaySurface(HWComposer& hwc, int disp, 54 const sp<IGraphicBufferProducer>& sink, 55 const String8& name); 56 57 virtual sp<IGraphicBufferProducer> getIGraphicBufferProducer() const; 58 59 virtual status_t compositionComplete(); 60 virtual status_t advanceFrame(); 61 virtual void onFrameCommitted(const sp<Fence>& fence); 62 virtual void dump(String8& result) const; 63 64private: 65 virtual ~VirtualDisplaySurface(); 66 67 // immutable after construction 68 HWComposer& mHwc; 69 int mDisplayId; 70 sp<BufferQueueInterposer> mSource; 71 String8 mName; 72 73 // mutable, must be synchronized with mMutex 74 Mutex mMutex; 75 sp<GraphicBuffer> mAcquiredBuffer; 76}; 77 78// --------------------------------------------------------------------------- 79} // namespace android 80// --------------------------------------------------------------------------- 81 82#endif // ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H 83 84