2 * Copyright 2013 The Android Open Source Project
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 #ifndef ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
18 #define ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
20 #include <gui/ConsumerBase.h>
21 #include <gui/IGraphicBufferProducer.h>
23 #include "DisplaySurface.h"
25 // ---------------------------------------------------------------------------
27 // ---------------------------------------------------------------------------
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.
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
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.
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.
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
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.
70 class VirtualDisplaySurface : public DisplaySurface,
71 public BnGraphicBufferProducer,
72 private ConsumerBase {
74 VirtualDisplaySurface(HWComposer& hwc, int32_t dispId,
75 const sp<IGraphicBufferProducer>& sink,
76 const sp<BufferQueue>& bq,
80 // DisplaySurface interface
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;
90 enum Source {SOURCE_SINK = 0, SOURCE_SCRATCH = 1};
92 virtual ~VirtualDisplaySurface();
95 // IGraphicBufferProducer interface, used by the GLES driver.
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);
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();
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);
129 // Immutable after construction
132 const int32_t mDisplayId;
133 const String8 mDisplayName;
134 sp<IGraphicBufferProducer> mSource[2]; // indexed by SOURCE_*
140 // To avoid buffer reallocations, we track the buffer usage and format
141 // we used on the previous frame and use it again on the new frame. If
142 // the composition type changes or the GLES driver starts requesting
143 // different usage/format, we'll get a new buffer.
144 uint32_t mOutputFormat;
145 uint32_t mOutputUsage;
147 // Since we present a single producer interface to the GLES driver, but
148 // are internally muxing between the sink and scratch producers, we have
149 // to keep track of which source last returned each producer slot from
150 // dequeueBuffer. Each bit in mLastSlotSource corresponds to a producer
151 // slot. Both mProducerSlotSource and mProducerBuffers are indexed by a
152 // "producer slot"; see the mapSlot*() functions.
153 uint32_t mProducerSlotSource;
154 sp<GraphicBuffer> mProducerBuffers[BufferQueue::NUM_BUFFER_SLOTS];
156 // The QueueBufferOutput with the latest info from the sink, and with the
157 // transform hint cleared. Since we defer queueBuffer from the GLES driver
158 // to the sink, we have to return the previous version.
159 QueueBufferOutput mQueueBufferOutput;
165 // Composition type and GLES buffer source for the current frame.
166 // Valid after prepareFrame(), cleared in onFrameCommitted.
167 CompositionType mCompositionType;
169 // Details of the current sink buffer. These become valid when a buffer is
170 // dequeued from the sink, and are used when queueing the buffer.
171 uint32_t mSinkBufferWidth, mSinkBufferHeight;
173 // mFbFence is the fence HWC should wait for before reading the framebuffer
177 // mOutputFence is the fence HWC should wait for before writing to the
179 sp<Fence> mOutputFence;
181 // Producer slot numbers for the buffers to use for HWC framebuffer target
184 int mOutputProducerSlot;
186 // Debug only -- track the sequence of events in each frame so we can make
187 // sure they happen in the order we expect. This class implicitly models
188 // a state machine; this enum/variable makes it explicit.
190 // +-----------+-------------------+-------------+
191 // | State | Event || Next State |
192 // +-----------+-------------------+-------------+
193 // | IDLE | beginFrame || BEGUN |
194 // | BEGUN | prepareFrame || PREPARED |
195 // | PREPARED | dequeueBuffer [1] || GLES |
196 // | PREPARED | advanceFrame [2] || HWC |
197 // | GLES | queueBuffer || GLES_DONE |
198 // | GLES_DONE | advanceFrame || HWC |
199 // | HWC | onFrameCommitted || IDLE |
200 // +-----------+-------------------++------------+
201 // [1] COMPOSITION_GLES and COMPOSITION_MIXED frames.
202 // [2] COMPOSITION_HWC frames.
205 // no buffer dequeued, don't know anything about the next frame
207 // output buffer dequeued, framebuffer source not yet known
209 // output buffer dequeued, framebuffer source known but not provided
212 // GLES driver has a buffer dequeued
214 // GLES driver has queued the buffer, we haven't sent it to HWC yet
216 // HWC has the buffer for this frame
220 CompositionType mDbgLastCompositionType;
222 const char* dbgStateStr() const;
223 static const char* dbgSourceStr(Source s);
226 // ---------------------------------------------------------------------------
227 } // namespace android
228 // ---------------------------------------------------------------------------
230 #endif // ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H