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 // --------------------------------------------------------------------------- 26 namespace android { 27 // --------------------------------------------------------------------------- 28 29 class 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 */ 70 class VirtualDisplaySurface : public DisplaySurface, 71 public BnGraphicBufferProducer, 72 private ConsumerBase { 73 public: 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(); 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 89 private: 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); 108 109 // 110 // Utility methods 111 // 112 static Source fbSourceForCompositionType(CompositionType type); 113 status_t dequeueBuffer(Source source, uint32_t format, uint32_t usage, 114 int* sslot, sp<Fence>* fence); 115 void updateQueueBufferOutput(const QueueBufferOutput& qbo); 116 void resetPerFrameState(); 117 status_t refreshOutputBuffer(); 118 119 // Both the sink and scratch buffer pools have their own set of slots 120 // ("source slots", or "sslot"). We have to merge these into the single 121 // set of slots used by the GLES producer ("producer slots" or "pslot") and 122 // internally in the VirtualDisplaySurface. To minimize the number of times 123 // a producer slot switches which source it comes from, we map source slot 124 // numbers to producer slot numbers differently for each source. 125 static int mapSource2ProducerSlot(Source source, int sslot); 126 static int mapProducer2SourceSlot(Source source, int pslot); 127 128 // 129 // Immutable after construction 130 // 131 HWComposer& mHwc; 132 const int32_t mDisplayId; 133 const String8 mDisplayName; 134 sp<IGraphicBufferProducer> mSource[2]; // indexed by SOURCE_* 135 uint32_t mDefaultOutputFormat; 136 137 // 138 // Inter-frame state 139 // 140 141 // To avoid buffer reallocations, we track the buffer usage and format 142 // we used on the previous frame and use it again on the new frame. If 143 // the composition type changes or the GLES driver starts requesting 144 // different usage/format, we'll get a new buffer. 145 uint32_t mOutputFormat; 146 uint32_t mOutputUsage; 147 148 // Since we present a single producer interface to the GLES driver, but 149 // are internally muxing between the sink and scratch producers, we have 150 // to keep track of which source last returned each producer slot from 151 // dequeueBuffer. Each bit in mLastSlotSource corresponds to a producer 152 // slot. Both mProducerSlotSource and mProducerBuffers are indexed by a 153 // "producer slot"; see the mapSlot*() functions. 154 uint32_t mProducerSlotSource; 155 sp<GraphicBuffer> mProducerBuffers[BufferQueue::NUM_BUFFER_SLOTS]; 156 157 // The QueueBufferOutput with the latest info from the sink, and with the 158 // transform hint cleared. Since we defer queueBuffer from the GLES driver 159 // to the sink, we have to return the previous version. 160 QueueBufferOutput mQueueBufferOutput; 161 162 // 163 // Intra-frame state 164 // 165 166 // Composition type and GLES buffer source for the current frame. 167 // Valid after prepareFrame(), cleared in onFrameCommitted. 168 CompositionType mCompositionType; 169 170 // Details of the current sink buffer. These become valid when a buffer is 171 // dequeued from the sink, and are used when queueing the buffer. 172 uint32_t mSinkBufferWidth, mSinkBufferHeight; 173 174 // mFbFence is the fence HWC should wait for before reading the framebuffer 175 // target buffer. 176 sp<Fence> mFbFence; 177 178 // mOutputFence is the fence HWC should wait for before writing to the 179 // output buffer. 180 sp<Fence> mOutputFence; 181 182 // Producer slot numbers for the buffers to use for HWC framebuffer target 183 // and output. 184 int mFbProducerSlot; 185 int mOutputProducerSlot; 186 187 // Debug only -- track the sequence of events in each frame so we can make 188 // sure they happen in the order we expect. This class implicitly models 189 // a state machine; this enum/variable makes it explicit. 190 // 191 // +-----------+-------------------+-------------+ 192 // | State | Event || Next State | 193 // +-----------+-------------------+-------------+ 194 // | IDLE | beginFrame || BEGUN | 195 // | BEGUN | prepareFrame || PREPARED | 196 // | PREPARED | dequeueBuffer [1] || GLES | 197 // | PREPARED | advanceFrame [2] || HWC | 198 // | GLES | queueBuffer || GLES_DONE | 199 // | GLES_DONE | advanceFrame || HWC | 200 // | HWC | onFrameCommitted || IDLE | 201 // +-----------+-------------------++------------+ 202 // [1] COMPOSITION_GLES and COMPOSITION_MIXED frames. 203 // [2] COMPOSITION_HWC frames. 204 // 205 enum DbgState { 206 // no buffer dequeued, don't know anything about the next frame 207 DBG_STATE_IDLE, 208 // output buffer dequeued, framebuffer source not yet known 209 DBG_STATE_BEGUN, 210 // output buffer dequeued, framebuffer source known but not provided 211 // to GLES yet. 212 DBG_STATE_PREPARED, 213 // GLES driver has a buffer dequeued 214 DBG_STATE_GLES, 215 // GLES driver has queued the buffer, we haven't sent it to HWC yet 216 DBG_STATE_GLES_DONE, 217 // HWC has the buffer for this frame 218 DBG_STATE_HWC, 219 }; 220 DbgState mDbgState; 221 CompositionType mDbgLastCompositionType; 222 223 const char* dbgStateStr() const; 224 static const char* dbgSourceStr(Source s); 225 }; 226 227 // --------------------------------------------------------------------------- 228 } // namespace android 229 // --------------------------------------------------------------------------- 230 231 #endif // ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H 232 233