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Side by Side Diff: cc/CCDamageTracker.cpp

Issue 11122003: [cc] Rename all cc/ filenames to Chromium style (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: Created 8 years, 2 months ago
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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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