VirtualDisplaySurface.h revision 399184a4cd728ea1421fb0bc1722274a29e38f4a
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 <gui/ConsumerBase.h> 21#include <gui/IGraphicBufferProducer.h> 22 23#include "DisplaySurface.h" 24 25// --------------------------------------------------------------------------- 26namespace android { 27// --------------------------------------------------------------------------- 28 29class HWComposer; 30 31/* This DisplaySurface implementation supports virtual displays, where GLES 32 * and/or HWC compose into a buffer that is then passed to an arbitrary 33 * consumer (the sink) running in another process. 34 * 35 * The simplest case is when the virtual display will never use the h/w 36 * composer -- either the h/w composer doesn't support writing to buffers, or 37 * there are more virtual displays than it supports simultaneously. In this 38 * case, the GLES driver works directly with the output buffer queue, and 39 * calls to the VirtualDisplay from SurfaceFlinger and DisplayHardware do 40 * nothing. 41 * 42 * If h/w composer might be used, then each frame will fall into one of three 43 * configurations: GLES-only, HWC-only, and MIXED composition. In all of these, 44 * we must provide a FB target buffer and output buffer for the HWC set() call. 45 * 46 * In GLES-only composition, the GLES driver is given a buffer from the sink to 47 * render into. When the GLES driver queues the buffer to the 48 * VirtualDisplaySurface, the VirtualDisplaySurface holds onto it instead of 49 * immediately queueing it to the sink. The buffer is used as both the FB 50 * target and output buffer for HWC, though on these frames the HWC doesn't 51 * do any work for this display and doesn't write to the output buffer. After 52 * composition is complete, the buffer is queued to the sink. 53 * 54 * In HWC-only composition, the VirtualDisplaySurface dequeues a buffer from 55 * the sink and passes it to HWC as both the FB target buffer and output 56 * buffer. The HWC doesn't need to read from the FB target buffer, but does 57 * write to the output buffer. After composition is complete, the buffer is 58 * queued to the sink. 59 * 60 * On MIXED frames, things become more complicated, since some h/w composer 61 * implementations can't read from and write to the same buffer. This class has 62 * an internal BufferQueue that it uses as a scratch buffer pool. The GLES 63 * driver is given a scratch buffer to render into. When it finishes rendering, 64 * the buffer is queued and then immediately acquired by the 65 * VirtualDisplaySurface. The scratch buffer is then used as the FB target 66 * buffer for HWC, and a separate buffer is dequeued from the sink and used as 67 * the HWC output buffer. When HWC composition is complete, the scratch buffer 68 * is released and the output buffer is queued to the sink. 69 */ 70class VirtualDisplaySurface : public DisplaySurface, 71 public BnGraphicBufferProducer, 72 private ConsumerBase { 73public: 74 VirtualDisplaySurface(HWComposer& hwc, int32_t dispId, 75 const sp<IGraphicBufferProducer>& sink, 76 const sp<BufferQueue>& bq, 77 const String8& name); 78 79 // 80 // DisplaySurface interface 81 // 82 virtual status_t beginFrame(bool mustRecompose); 83 virtual status_t prepareFrame(CompositionType compositionType); 84 virtual status_t compositionComplete(); 85 virtual status_t advanceFrame(); 86 virtual void onFrameCommitted(); 87 virtual void dump(String8& result) const; 88 89private: 90 enum Source {SOURCE_SINK = 0, SOURCE_SCRATCH = 1}; 91 92 virtual ~VirtualDisplaySurface(); 93 94 // 95 // IGraphicBufferProducer interface, used by the GLES driver. 96 // 97 virtual status_t requestBuffer(int pslot, sp<GraphicBuffer>* outBuf); 98 virtual status_t setBufferCount(int bufferCount); 99 virtual status_t dequeueBuffer(int* pslot, sp<Fence>* fence, bool async, 100 uint32_t w, uint32_t h, uint32_t format, uint32_t usage); 101 virtual status_t queueBuffer(int pslot, 102 const QueueBufferInput& input, QueueBufferOutput* output); 103 virtual void cancelBuffer(int pslot, const sp<Fence>& fence); 104 virtual int query(int what, int* value); 105 virtual status_t connect(const sp<IBinder>& token, 106 int api, bool producerControlledByApp, QueueBufferOutput* output); 107 virtual status_t disconnect(int api); 108 virtual status_t setSidebandStream(const sp<NativeHandle>& stream); 109 110 // 111 // Utility methods 112 // 113 static Source fbSourceForCompositionType(CompositionType type); 114 status_t dequeueBuffer(Source source, uint32_t format, uint32_t usage, 115 int* sslot, sp<Fence>* fence); 116 void updateQueueBufferOutput(const QueueBufferOutput& qbo); 117 void resetPerFrameState(); 118 status_t refreshOutputBuffer(); 119 120 // Both the sink and scratch buffer pools have their own set of slots 121 // ("source slots", or "sslot"). We have to merge these into the single 122 // set of slots used by the GLES producer ("producer slots" or "pslot") and 123 // internally in the VirtualDisplaySurface. To minimize the number of times 124 // a producer slot switches which source it comes from, we map source slot 125 // numbers to producer slot numbers differently for each source. 126 static int mapSource2ProducerSlot(Source source, int sslot); 127 static int mapProducer2SourceSlot(Source source, int pslot); 128 129 // 130 // Immutable after construction 131 // 132 HWComposer& mHwc; 133 const int32_t mDisplayId; 134 const String8 mDisplayName; 135 sp<IGraphicBufferProducer> mSource[2]; // indexed by SOURCE_* 136 uint32_t mDefaultOutputFormat; 137 138 // 139 // Inter-frame state 140 // 141 142 // To avoid buffer reallocations, we track the buffer usage and format 143 // we used on the previous frame and use it again on the new frame. If 144 // the composition type changes or the GLES driver starts requesting 145 // different usage/format, we'll get a new buffer. 146 uint32_t mOutputFormat; 147 uint32_t mOutputUsage; 148 149 // Since we present a single producer interface to the GLES driver, but 150 // are internally muxing between the sink and scratch producers, we have 151 // to keep track of which source last returned each producer slot from 152 // dequeueBuffer. Each bit in mLastSlotSource corresponds to a producer 153 // slot. Both mProducerSlotSource and mProducerBuffers are indexed by a 154 // "producer slot"; see the mapSlot*() functions. 155 uint32_t mProducerSlotSource; 156 sp<GraphicBuffer> mProducerBuffers[BufferQueue::NUM_BUFFER_SLOTS]; 157 158 // The QueueBufferOutput with the latest info from the sink, and with the 159 // transform hint cleared. Since we defer queueBuffer from the GLES driver 160 // to the sink, we have to return the previous version. 161 QueueBufferOutput mQueueBufferOutput; 162 163 // 164 // Intra-frame state 165 // 166 167 // Composition type and GLES buffer source for the current frame. 168 // Valid after prepareFrame(), cleared in onFrameCommitted. 169 CompositionType mCompositionType; 170 171 // Details of the current sink buffer. These become valid when a buffer is 172 // dequeued from the sink, and are used when queueing the buffer. 173 uint32_t mSinkBufferWidth, mSinkBufferHeight; 174 175 // mFbFence is the fence HWC should wait for before reading the framebuffer 176 // target buffer. 177 sp<Fence> mFbFence; 178 179 // mOutputFence is the fence HWC should wait for before writing to the 180 // output buffer. 181 sp<Fence> mOutputFence; 182 183 // Producer slot numbers for the buffers to use for HWC framebuffer target 184 // and output. 185 int mFbProducerSlot; 186 int mOutputProducerSlot; 187 188 // Debug only -- track the sequence of events in each frame so we can make 189 // sure they happen in the order we expect. This class implicitly models 190 // a state machine; this enum/variable makes it explicit. 191 // 192 // +-----------+-------------------+-------------+ 193 // | State | Event || Next State | 194 // +-----------+-------------------+-------------+ 195 // | IDLE | beginFrame || BEGUN | 196 // | BEGUN | prepareFrame || PREPARED | 197 // | PREPARED | dequeueBuffer [1] || GLES | 198 // | PREPARED | advanceFrame [2] || HWC | 199 // | GLES | queueBuffer || GLES_DONE | 200 // | GLES_DONE | advanceFrame || HWC | 201 // | HWC | onFrameCommitted || IDLE | 202 // +-----------+-------------------++------------+ 203 // [1] COMPOSITION_GLES and COMPOSITION_MIXED frames. 204 // [2] COMPOSITION_HWC frames. 205 // 206 enum DbgState { 207 // no buffer dequeued, don't know anything about the next frame 208 DBG_STATE_IDLE, 209 // output buffer dequeued, framebuffer source not yet known 210 DBG_STATE_BEGUN, 211 // output buffer dequeued, framebuffer source known but not provided 212 // to GLES yet. 213 DBG_STATE_PREPARED, 214 // GLES driver has a buffer dequeued 215 DBG_STATE_GLES, 216 // GLES driver has queued the buffer, we haven't sent it to HWC yet 217 DBG_STATE_GLES_DONE, 218 // HWC has the buffer for this frame 219 DBG_STATE_HWC, 220 }; 221 DbgState mDbgState; 222 CompositionType mDbgLastCompositionType; 223 224 const char* dbgStateStr() const; 225 static const char* dbgSourceStr(Source s); 226 227 bool mMustRecompose; 228}; 229 230// --------------------------------------------------------------------------- 231} // namespace android 232// --------------------------------------------------------------------------- 233 234#endif // ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H 235 236