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1 // Copyright 2011 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "config.h" | |
6 | |
7 #if USE(ACCELERATED_COMPOSITING) | |
8 | |
9 #include "CCDamageTracker.h" | |
10 | |
11 #include "CCLayerImpl.h" | |
12 #include "CCLayerTreeHostCommon.h" | |
13 #include "CCMathUtil.h" | |
14 #include "CCRenderSurface.h" | |
15 #include <public/WebFilterOperations.h> | |
16 | |
17 using WebKit::WebTransformationMatrix; | |
18 | |
19 namespace cc { | |
20 | |
21 scoped_ptr<CCDamageTracker> CCDamageTracker::create() | |
22 { | |
23 return make_scoped_ptr(new CCDamageTracker()); | |
24 } | |
25 | |
26 CCDamageTracker::CCDamageTracker() | |
27 : m_forceFullDamageNextUpdate(false), | |
28 m_currentRectHistory(new RectMap), | |
29 m_nextRectHistory(new RectMap) | |
30 { | |
31 } | |
32 | |
33 CCDamageTracker::~CCDamageTracker() | |
34 { | |
35 } | |
36 | |
37 static inline void expandRectWithFilters(FloatRect& rect, const WebKit::WebFilte
rOperations& filters) | |
38 { | |
39 int top, right, bottom, left; | |
40 filters.getOutsets(top, right, bottom, left); | |
41 rect.move(-left, -top); | |
42 rect.expand(left + right, top + bottom); | |
43 } | |
44 | |
45 static inline void expandDamageRectInsideRectWithFilters(FloatRect& damageRect,
const FloatRect& preFilterRect, const WebKit::WebFilterOperations& filters) | |
46 { | |
47 FloatRect expandedDamageRect = damageRect; | |
48 expandRectWithFilters(expandedDamageRect, filters); | |
49 FloatRect filterRect = preFilterRect; | |
50 expandRectWithFilters(filterRect, filters); | |
51 | |
52 expandedDamageRect.intersect(filterRect); | |
53 damageRect.unite(expandedDamageRect); | |
54 } | |
55 | |
56 void CCDamageTracker::updateDamageTrackingState(const std::vector<CCLayerImpl*>&
layerList, int targetSurfaceLayerID, bool targetSurfacePropertyChangedOnlyFromD
escendant, const IntRect& targetSurfaceContentRect, CCLayerImpl* targetSurfaceMa
skLayer, const WebKit::WebFilterOperations& filters) | |
57 { | |
58 // | |
59 // This function computes the "damage rect" of a target surface, and updates
the state | |
60 // that is used to correctly track damage across frames. The damage rect is
the region | |
61 // of the surface that may have changed and needs to be redrawn. This can be
used to | |
62 // scissor what is actually drawn, to save GPU computation and bandwidth. | |
63 // | |
64 // The surface's damage rect is computed as the union of all possible change
s that | |
65 // have happened to the surface since the last frame was drawn. This include
s: | |
66 // - any changes for existing layers/surfaces that contribute to the targe
t surface | |
67 // - layers/surfaces that existed in the previous frame, but no longer exi
st. | |
68 // | |
69 // The basic algorithm for computing the damage region is as follows: | |
70 // | |
71 // 1. compute damage caused by changes in active/new layers | |
72 // for each layer in the layerList: | |
73 // if the layer is actually a renderSurface: | |
74 // add the surface's damage to our target surface. | |
75 // else | |
76 // add the layer's damage to the target surface. | |
77 // | |
78 // 2. compute damage caused by the target surface's mask, if it exists. | |
79 // | |
80 // 3. compute damage caused by old layers/surfaces that no longer exist | |
81 // for each leftover layer: | |
82 // add the old layer/surface bounds to the target surface damage. | |
83 // | |
84 // 4. combine all partial damage rects to get the full damage rect. | |
85 // | |
86 // Additional important points: | |
87 // | |
88 // - This algorithm is implicitly recursive; it assumes that descendant surf
aces have | |
89 // already computed their damage. | |
90 // | |
91 // - Changes to layers/surfaces indicate "damage" to the target surface; If
a layer is | |
92 // not changed, it does NOT mean that the layer can skip drawing. All laye
rs that | |
93 // overlap the damaged region still need to be drawn. For example, if a la
yer | |
94 // changed its opacity, then layers underneath must be re-drawn as well, e
ven if | |
95 // they did not change. | |
96 // | |
97 // - If a layer/surface property changed, the old bounds and new bounds may
overlap... | |
98 // i.e. some of the exposed region may not actually be exposing anything.
But this | |
99 // does not artificially inflate the damage rect. If the layer changed, it
s entire | |
100 // old bounds would always need to be redrawn, regardless of how much it o
verlaps | |
101 // with the layer's new bounds, which also need to be entirely redrawn. | |
102 // | |
103 // - See comments in the rest of the code to see what exactly is considered
a "change" | |
104 // in a layer/surface. | |
105 // | |
106 // - To correctly manage exposed rects, two RectMaps are maintained: | |
107 // | |
108 // 1. The "current" map contains all the layer bounds that contributed
to the | |
109 // previous frame (even outside the previous damaged area). If a lay
er changes | |
110 // or does not exist anymore, those regions are then exposed and dam
age the | |
111 // target surface. As the algorithm progresses, entries are removed
from the | |
112 // map until it has only leftover layers that no longer exist. | |
113 // | |
114 // 2. The "next" map starts out empty, and as the algorithm progresses,
every | |
115 // layer/surface that contributes to the surface is added to the map
. | |
116 // | |
117 // 3. After the damage rect is computed, the two maps are swapped, so t
hat the | |
118 // damage tracker is ready for the next frame. | |
119 // | |
120 | |
121 // These functions cannot be bypassed with early-exits, even if we know what
the | |
122 // damage will be for this frame, because we need to update the damage track
er state | |
123 // to correctly track the next frame. | |
124 FloatRect damageFromActiveLayers = trackDamageFromActiveLayers(layerList, ta
rgetSurfaceLayerID); | |
125 FloatRect damageFromSurfaceMask = trackDamageFromSurfaceMask(targetSurfaceMa
skLayer); | |
126 FloatRect damageFromLeftoverRects = trackDamageFromLeftoverRects(); | |
127 | |
128 FloatRect damageRectForThisUpdate; | |
129 | |
130 if (m_forceFullDamageNextUpdate || targetSurfacePropertyChangedOnlyFromDesce
ndant) { | |
131 damageRectForThisUpdate = targetSurfaceContentRect; | |
132 m_forceFullDamageNextUpdate = false; | |
133 } else { | |
134 // FIXME: can we clamp this damage to the surface's content rect? (affec
ts performance, but not correctness) | |
135 damageRectForThisUpdate = damageFromActiveLayers; | |
136 damageRectForThisUpdate.uniteIfNonZero(damageFromSurfaceMask); | |
137 damageRectForThisUpdate.uniteIfNonZero(damageFromLeftoverRects); | |
138 | |
139 if (filters.hasFilterThatMovesPixels()) | |
140 expandRectWithFilters(damageRectForThisUpdate, filters); | |
141 } | |
142 | |
143 // Damage accumulates until we are notified that we actually did draw on tha
t frame. | |
144 m_currentDamageRect.uniteIfNonZero(damageRectForThisUpdate); | |
145 | |
146 // The next history map becomes the current map for the next frame. Note thi
s must | |
147 // happen every frame to correctly track changes, even if damage accumulates
over | |
148 // multiple frames before actually being drawn. | |
149 swap(m_currentRectHistory, m_nextRectHistory); | |
150 } | |
151 | |
152 FloatRect CCDamageTracker::removeRectFromCurrentFrame(int layerID, bool& layerIs
New) | |
153 { | |
154 layerIsNew = !m_currentRectHistory->contains(layerID); | |
155 | |
156 // take() will remove the entry from the map, or if not found, return a defa
ult (empty) rect. | |
157 return m_currentRectHistory->take(layerID); | |
158 } | |
159 | |
160 void CCDamageTracker::saveRectForNextFrame(int layerID, const FloatRect& targetS
paceRect) | |
161 { | |
162 // This layer should not yet exist in next frame's history. | |
163 ASSERT(layerID > 0); | |
164 ASSERT(m_nextRectHistory->find(layerID) == m_nextRectHistory->end()); | |
165 m_nextRectHistory->set(layerID, targetSpaceRect); | |
166 } | |
167 | |
168 FloatRect CCDamageTracker::trackDamageFromActiveLayers(const std::vector<CCLayer
Impl*>& layerList, int targetSurfaceLayerID) | |
169 { | |
170 FloatRect damageRect = FloatRect(); | |
171 | |
172 for (unsigned layerIndex = 0; layerIndex < layerList.size(); ++layerIndex) { | |
173 // Visit layers in back-to-front order. | |
174 CCLayerImpl* layer = layerList[layerIndex]; | |
175 | |
176 if (CCLayerTreeHostCommon::renderSurfaceContributesToTarget<CCLayerImpl>
(layer, targetSurfaceLayerID)) | |
177 extendDamageForRenderSurface(layer, damageRect); | |
178 else | |
179 extendDamageForLayer(layer, damageRect); | |
180 } | |
181 | |
182 return damageRect; | |
183 } | |
184 | |
185 FloatRect CCDamageTracker::trackDamageFromSurfaceMask(CCLayerImpl* targetSurface
MaskLayer) | |
186 { | |
187 FloatRect damageRect = FloatRect(); | |
188 | |
189 if (!targetSurfaceMaskLayer) | |
190 return damageRect; | |
191 | |
192 // Currently, if there is any change to the mask, we choose to damage the en
tire | |
193 // surface. This could potentially be optimized later, but it is not expecte
d to be a | |
194 // common case. | |
195 if (targetSurfaceMaskLayer->layerPropertyChanged() || !targetSurfaceMaskLaye
r->updateRect().isEmpty()) | |
196 damageRect = FloatRect(FloatPoint::zero(), FloatSize(targetSurfaceMaskLa
yer->bounds())); | |
197 | |
198 return damageRect; | |
199 } | |
200 | |
201 FloatRect CCDamageTracker::trackDamageFromLeftoverRects() | |
202 { | |
203 // After computing damage for all active layers, any leftover items in the c
urrent | |
204 // rect history correspond to layers/surfaces that no longer exist. So, thes
e regions | |
205 // are now exposed on the target surface. | |
206 | |
207 FloatRect damageRect = FloatRect(); | |
208 | |
209 for (RectMap::iterator it = m_currentRectHistory->begin(); it != m_currentRe
ctHistory->end(); ++it) | |
210 #if WTF_NEW_HASHMAP_ITERATORS_INTERFACE | |
211 damageRect.unite(it->value); | |
212 #else | |
213 damageRect.unite(it->second); | |
214 #endif | |
215 | |
216 m_currentRectHistory->clear(); | |
217 | |
218 return damageRect; | |
219 } | |
220 | |
221 static bool layerNeedsToRedrawOntoItsTargetSurface(CCLayerImpl* layer) | |
222 { | |
223 // If the layer does NOT own a surface but has SurfacePropertyChanged, | |
224 // this means that its target surface is affected and needs to be redrawn. | |
225 // However, if the layer DOES own a surface, then the SurfacePropertyChanged
| |
226 // flag should not be used here, because that flag represents whether the | |
227 // layer's surface has changed. | |
228 if (layer->renderSurface()) | |
229 return layer->layerPropertyChanged(); | |
230 return layer->layerPropertyChanged() || layer->layerSurfacePropertyChanged()
; | |
231 } | |
232 | |
233 void CCDamageTracker::extendDamageForLayer(CCLayerImpl* layer, FloatRect& target
DamageRect) | |
234 { | |
235 // There are two ways that a layer can damage a region of the target surface
: | |
236 // 1. Property change (e.g. opacity, position, transforms): | |
237 // - the entire region of the layer itself damages the surface. | |
238 // - the old layer region also damages the surface, because this regi
on is now exposed. | |
239 // - note that in many cases the old and new layer rects may overlap,
which is fine. | |
240 // | |
241 // 2. Repaint/update: If a region of the layer that was repainted/updated,
that | |
242 // region damages the surface. | |
243 // | |
244 // Property changes take priority over update rects. | |
245 // | |
246 // This method is called when we want to consider how a layer contributes to
its | |
247 // targetRenderSurface, even if that layer owns the targetRenderSurface itse
lf. | |
248 // To consider how a layer's targetSurface contributes to the ancestorSurfac
e, | |
249 // extendDamageForRenderSurface() must be called instead. | |
250 | |
251 bool layerIsNew = false; | |
252 FloatRect oldRectInTargetSpace = removeRectFromCurrentFrame(layer->id(), lay
erIsNew); | |
253 | |
254 FloatRect rectInTargetSpace = CCMathUtil::mapClippedRect(layer->drawTransfor
m(), FloatRect(FloatPoint::zero(), layer->contentBounds())); | |
255 saveRectForNextFrame(layer->id(), rectInTargetSpace); | |
256 | |
257 if (layerIsNew || layerNeedsToRedrawOntoItsTargetSurface(layer)) { | |
258 // If a layer is new or has changed, then its entire layer rect affects
the target surface. | |
259 targetDamageRect.uniteIfNonZero(rectInTargetSpace); | |
260 | |
261 // The layer's old region is now exposed on the target surface, too. | |
262 // Note oldRectInTargetSpace is already in target space. | |
263 targetDamageRect.uniteIfNonZero(oldRectInTargetSpace); | |
264 } else if (!layer->updateRect().isEmpty()) { | |
265 // If the layer properties havent changed, then the the target surface i
s only | |
266 // affected by the layer's update area, which could be empty. | |
267 FloatRect updateContentRect = layer->updateRect(); | |
268 float widthScale = layer->contentBounds().width() / static_cast<float>(l
ayer->bounds().width()); | |
269 float heightScale = layer->contentBounds().height() / static_cast<float>
(layer->bounds().height()); | |
270 updateContentRect.scale(widthScale, heightScale); | |
271 | |
272 FloatRect updateRectInTargetSpace = CCMathUtil::mapClippedRect(layer->dr
awTransform(), updateContentRect); | |
273 targetDamageRect.uniteIfNonZero(updateRectInTargetSpace); | |
274 } | |
275 } | |
276 | |
277 void CCDamageTracker::extendDamageForRenderSurface(CCLayerImpl* layer, FloatRect
& targetDamageRect) | |
278 { | |
279 // There are two ways a "descendant surface" can damage regions of the "targ
et surface": | |
280 // 1. Property change: | |
281 // - a surface's geometry can change because of | |
282 // - changes to descendants (i.e. the subtree) that affect the su
rface's content rect | |
283 // - changes to ancestor layers that propagate their property cha
nges to their entire subtree. | |
284 // - just like layers, both the old surface rect and new surface rect
will | |
285 // damage the target surface in this case. | |
286 // | |
287 // 2. Damage rect: This surface may have been damaged by its own layerList
as well, and that damage | |
288 // should propagate to the target surface. | |
289 // | |
290 | |
291 CCRenderSurface* renderSurface = layer->renderSurface(); | |
292 | |
293 bool surfaceIsNew = false; | |
294 FloatRect oldSurfaceRect = removeRectFromCurrentFrame(layer->id(), surfaceIs
New); | |
295 | |
296 FloatRect surfaceRectInTargetSpace = renderSurface->drawableContentRect(); /
/ already includes replica if it exists. | |
297 saveRectForNextFrame(layer->id(), surfaceRectInTargetSpace); | |
298 | |
299 FloatRect damageRectInLocalSpace; | |
300 if (surfaceIsNew || renderSurface->surfacePropertyChanged() || layer->layerS
urfacePropertyChanged()) { | |
301 // The entire surface contributes damage. | |
302 damageRectInLocalSpace = renderSurface->contentRect(); | |
303 | |
304 // The surface's old region is now exposed on the target surface, too. | |
305 targetDamageRect.uniteIfNonZero(oldSurfaceRect); | |
306 } else { | |
307 // Only the surface's damageRect will damage the target surface. | |
308 damageRectInLocalSpace = renderSurface->damageTracker()->currentDamageRe
ct(); | |
309 } | |
310 | |
311 // If there was damage, transform it to target space, and possibly contribut
e its reflection if needed. | |
312 if (!damageRectInLocalSpace.isEmpty()) { | |
313 const WebTransformationMatrix& drawTransform = renderSurface->drawTransf
orm(); | |
314 FloatRect damageRectInTargetSpace = CCMathUtil::mapClippedRect(drawTrans
form, damageRectInLocalSpace); | |
315 targetDamageRect.uniteIfNonZero(damageRectInTargetSpace); | |
316 | |
317 if (layer->replicaLayer()) { | |
318 const WebTransformationMatrix& replicaDrawTransform = renderSurface-
>replicaDrawTransform(); | |
319 targetDamageRect.uniteIfNonZero(CCMathUtil::mapClippedRect(replicaDr
awTransform, damageRectInLocalSpace)); | |
320 } | |
321 } | |
322 | |
323 // If there was damage on the replica's mask, then the target surface receiv
es that damage as well. | |
324 if (layer->replicaLayer() && layer->replicaLayer()->maskLayer()) { | |
325 CCLayerImpl* replicaMaskLayer = layer->replicaLayer()->maskLayer(); | |
326 | |
327 bool replicaIsNew = false; | |
328 removeRectFromCurrentFrame(replicaMaskLayer->id(), replicaIsNew); | |
329 | |
330 const WebTransformationMatrix& replicaDrawTransform = renderSurface->rep
licaDrawTransform(); | |
331 FloatRect replicaMaskLayerRect = CCMathUtil::mapClippedRect(replicaDrawT
ransform, FloatRect(FloatPoint::zero(), FloatSize(replicaMaskLayer->bounds().wid
th(), replicaMaskLayer->bounds().height()))); | |
332 saveRectForNextFrame(replicaMaskLayer->id(), replicaMaskLayerRect); | |
333 | |
334 // In the current implementation, a change in the replica mask damages t
he entire replica region. | |
335 if (replicaIsNew || replicaMaskLayer->layerPropertyChanged() || !replica
MaskLayer->updateRect().isEmpty()) | |
336 targetDamageRect.uniteIfNonZero(replicaMaskLayerRect); | |
337 } | |
338 | |
339 // If the layer has a background filter, this may cause pixels in our surfac
e to be expanded, so we will need to expand any damage | |
340 // at or below this layer. We expand the damage from this layer too, as we n
eed to readback those pixels from the surface with only | |
341 // the contents of layers below this one in them. This means we need to redr
aw any pixels in the surface being used for the blur in | |
342 // this layer this frame. | |
343 if (layer->backgroundFilters().hasFilterThatMovesPixels()) | |
344 expandDamageRectInsideRectWithFilters(targetDamageRect, surfaceRectInTar
getSpace, layer->backgroundFilters()); | |
345 } | |
346 | |
347 } // namespace cc | |
348 | |
349 #endif // USE(ACCELERATED_COMPOSITING) | |
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