src/gpu/graphite/DrawAtlas.cpp - skia - Git at Google

 /*
  * Copyright 2022 Google LLC
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "src/gpu/graphite/DrawAtlas.h"

 #include <memory>

 #include "include/gpu/graphite/Recorder.h"
 #include "include/private/SkTPin.h"
 #include "src/core/SkMathPriv.h"
 #include "src/core/SkOpts.h"
 #include "src/core/SkTraceEvent.h"
 #include "src/gpu/AtlasTypes.h"
 #include "src/gpu/graphite/Caps.h"
 #include "src/gpu/graphite/CommandTypes.h"
 #include "src/gpu/graphite/DrawContext.h"
 #include "src/gpu/graphite/RecorderPriv.h"
 #include "src/gpu/graphite/TextureProxy.h"

 namespace skgpu::graphite {

 #if defined(DUMP_ATLAS_DATA)
 static const constexpr bool kDumpAtlasData = true;
 #else
 static const constexpr bool kDumpAtlasData = false;
 #endif

 #ifdef SK_DEBUG
 void DrawAtlas::validate(const AtlasLocator& atlasLocator) const {
     // Verify that the plotIndex stored in the PlotLocator is consistent with the glyph rectangle
     int numPlotsX = fTextureWidth / fPlotWidth;
     int numPlotsY = fTextureHeight / fPlotHeight;

     int plotIndex = atlasLocator.plotIndex();
     auto topLeft = atlasLocator.topLeft();
     int plotX = topLeft.x() / fPlotWidth;
     int plotY = topLeft.y() / fPlotHeight;
     SkASSERT(plotIndex == (numPlotsY - plotY - 1) * numPlotsX + (numPlotsX - plotX - 1));
 }
 #endif

 std::unique_ptr<DrawAtlas> DrawAtlas::Make(SkColorType colorType, size_t bpp, int width,
                                            int height, int plotWidth, int plotHeight,
                                            AtlasGenerationCounter* generationCounter,
                                            AllowMultitexturing allowMultitexturing,
                                            PlotEvictionCallback* evictor,
                                            std::string_view label) {
     std::unique_ptr<DrawAtlas> atlas(new DrawAtlas(colorType, bpp, width, height,
                                                    plotWidth, plotHeight, generationCounter,
                                                    allowMultitexturing, label));

     if (evictor != nullptr) {
         atlas->fEvictionCallbacks.emplace_back(evictor);
     }
     return atlas;
 }

 ///////////////////////////////////////////////////////////////////////////////

 DrawAtlas::DrawAtlas(SkColorType colorType, size_t bpp, int width, int height,
                      int plotWidth, int plotHeight, AtlasGenerationCounter* generationCounter,
                      AllowMultitexturing allowMultitexturing, std::string_view label)
         : fColorType(colorType)
         , fBytesPerPixel(bpp)
         , fTextureWidth(width)
         , fTextureHeight(height)
         , fPlotWidth(plotWidth)
         , fPlotHeight(plotHeight)
         , fLabel(label)
         , fGenerationCounter(generationCounter)
         , fAtlasGeneration(fGenerationCounter->next())
         , fPrevFlushToken(DrawToken::AlreadyFlushedToken())
         , fFlushesSinceLastUse(0)
         , fMaxPages(AllowMultitexturing::kYes == allowMultitexturing ?
                             PlotLocator::kMaxMultitexturePages : 1)
         , fNumActivePages(0) {
     int numPlotsX = width/plotWidth;
     int numPlotsY = height/plotHeight;
     SkASSERT(numPlotsX * numPlotsY <= PlotLocator::kMaxPlots);
     SkASSERT(fPlotWidth * numPlotsX == fTextureWidth);
     SkASSERT(fPlotHeight * numPlotsY == fTextureHeight);

     fNumPlots = numPlotsX * numPlotsY;

     this->createPages(generationCounter);
 }

 inline void DrawAtlas::processEviction(PlotLocator plotLocator) {
     for (PlotEvictionCallback* evictor : fEvictionCallbacks) {
         evictor->evict(plotLocator);
     }

     fAtlasGeneration = fGenerationCounter->next();
 }

 inline bool DrawAtlas::updatePlot(AtlasLocator* atlasLocator, Plot* plot) {
     int pageIdx = plot->pageIndex();
     this->makeMRU(plot, pageIdx);

     // The actual upload will be created in recordUploads().

     atlasLocator->updatePlotLocator(plot->plotLocator());
     SkDEBUGCODE(this->validate(*atlasLocator);)
     return true;
 }

 bool DrawAtlas::addToPage(unsigned int pageIdx, int width, int height, const void* image,
                           AtlasLocator* atlasLocator) {
     SkASSERT(fProxies[pageIdx]);

     // look through all allocated plots for one we can share, in Most Recently Refed order
     PlotList::Iter plotIter;
     plotIter.init(fPages[pageIdx].fPlotList, PlotList::Iter::kHead_IterStart);

     for (Plot* plot = plotIter.get(); plot; plot = plotIter.next()) {
         if (plot->addSubImage(width, height, image, atlasLocator)) {
             return this->updatePlot(atlasLocator, plot);
         }
     }

     return false;
 }

 bool DrawAtlas::recordUploads(DrawContext* dc, Recorder* recorder) {
     TRACE_EVENT0("skia.gpu", TRACE_FUNC);
     for (uint32_t pageIdx = 0; pageIdx < fNumActivePages; ++pageIdx) {
         PlotList::Iter plotIter;
         plotIter.init(fPages[pageIdx].fPlotList, PlotList::Iter::kHead_IterStart);
         for (Plot* plot = plotIter.get(); plot; plot = plotIter.next()) {
             if (plot->needsUpload()) {
                 TextureProxy* proxy = fProxies[pageIdx].get();
                 SkASSERT(proxy);

                 const void* dataPtr;
                 SkIRect dstRect;
                 std::tie(dataPtr, dstRect) = plot->prepareForUpload();

                 std::vector<MipLevel> levels;
                 levels.push_back({dataPtr, fBytesPerPixel*fPlotWidth});

                 if (!dc->recordUpload(recorder, sk_ref_sp(proxy), fColorType, levels, dstRect)) {
                     return false;
                 }
             }
         }
     }
     return true;
 }

 // Number of atlas-related flushes beyond which we consider a plot to no longer be in use.
 //
 // This value is somewhat arbitrary -- the idea is to keep it low enough that
 // a page with unused plots will get removed reasonably quickly, but allow it
 // to hang around for a bit in case it's needed. The assumption is that flushes
 // are rare; i.e., we are not continually refreshing the frame.
 static constexpr auto kPlotRecentlyUsedCount = 32;
 static constexpr auto kAtlasRecentlyUsedCount = 128;

 DrawAtlas::ErrorCode DrawAtlas::addToAtlas(Recorder* recorder,
                                            int width, int height, const void* image,
                                            AtlasLocator* atlasLocator) {
     if (width > fPlotWidth || height > fPlotHeight) {
         return ErrorCode::kError;
     }

     // Look through each page to see if we can upload without having to flush
     // We prioritize this upload to the first pages, not the most recently used, to make it easier
     // to remove unused pages in reverse page order.
     for (unsigned int pageIdx = 0; pageIdx < fNumActivePages; ++pageIdx) {
         if (this->addToPage(pageIdx, width, height, image, atlasLocator)) {
             return ErrorCode::kSucceeded;
         }
     }

     // If the above fails, then see if the least recently used plot per page has already been
     // queued for upload if we're at max page allocation, or if the plot has aged out otherwise.
     // We wait until we've grown to the full number of pages to begin evicting already queued
     // plots so that we can maximize the opportunity for reuse.
     // As before we prioritize this upload to the first pages, not the most recently used.
     if (fNumActivePages == this->maxPages()) {
         for (unsigned int pageIdx = 0; pageIdx < fNumActivePages; ++pageIdx) {
             Plot* plot = fPages[pageIdx].fPlotList.tail();
             SkASSERT(plot);
             if (plot->lastUseToken() < recorder->priv().tokenTracker()->nextTokenToFlush()) {
                 this->processEvictionAndResetRects(plot);
                 SkDEBUGCODE(bool verify = )plot->addSubImage(width, height, image, atlasLocator);
                 SkASSERT(verify);
                 if (!this->updatePlot(atlasLocator, plot)) {
                     return ErrorCode::kError;
                 }
                 return ErrorCode::kSucceeded;
             }
         }
     } else {
         // If we haven't activated all the available pages, try to create a new one and add to it
         if (!this->activateNewPage(recorder)) {
             return ErrorCode::kError;
         }

         if (this->addToPage(fNumActivePages-1, width, height, image, atlasLocator)) {
             return ErrorCode::kSucceeded;
         } else {
             // If we fail to upload to a newly activated page then something has gone terribly
             // wrong - return an error
             return ErrorCode::kError;
         }
     }

     if (!fNumActivePages) {
         return ErrorCode::kError;
     }

     // All plots are currently in use by the current set of draws, so we need to fail. This
     // gives the Device a chance to snap the current set of uploads and draws, advance the draw
     // token, and call back into this function. The subsequent call will have plots available
     // for fresh uploads.
     return ErrorCode::kTryAgain;
 }

 void DrawAtlas::compact(DrawToken startTokenForNextFlush) {
     if (fNumActivePages < 1) {
         fPrevFlushToken = startTokenForNextFlush;
         return;
     }

     // For all plots, reset number of flushes since used if used this frame.
     PlotList::Iter plotIter;
     bool atlasUsedThisFlush = false;
     for (uint32_t pageIndex = 0; pageIndex < fNumActivePages; ++pageIndex) {
         plotIter.init(fPages[pageIndex].fPlotList, PlotList::Iter::kHead_IterStart);
         while (Plot* plot = plotIter.get()) {
             // Reset number of flushes since used
             if (plot->lastUseToken().inInterval(fPrevFlushToken, startTokenForNextFlush)) {
                 plot->resetFlushesSinceLastUsed();
                 atlasUsedThisFlush = true;
             }

             plotIter.next();
         }
     }

     if (atlasUsedThisFlush) {
         fFlushesSinceLastUse = 0;
     } else {
         ++fFlushesSinceLastUse;
     }

     // We only try to compact if the atlas was used in the recently completed flush or
     // hasn't been used in a long time.
     // This is to handle the case where a lot of text or path rendering has occurred but then just
     // a blinking cursor is drawn.
     if (atlasUsedThisFlush || fFlushesSinceLastUse > kAtlasRecentlyUsedCount) {
         SkTArray<Plot*> availablePlots;
         uint32_t lastPageIndex = fNumActivePages - 1;

         // For all plots but the last one, update number of flushes since used, and check to see
         // if there are any in the first pages that the last page can safely upload to.
         for (uint32_t pageIndex = 0; pageIndex < lastPageIndex; ++pageIndex) {
             if constexpr (kDumpAtlasData) {
                 SkDebugf("page %d: ", pageIndex);
             }

             plotIter.init(fPages[pageIndex].fPlotList, PlotList::Iter::kHead_IterStart);
             while (Plot* plot = plotIter.get()) {
                 // Update number of flushes since plot was last used
                 // We only increment the 'sinceLastUsed' count for flushes where the atlas was used
                 // to avoid deleting everything when we return to text drawing in the blinking
                 // cursor case
                 if (!plot->lastUseToken().inInterval(fPrevFlushToken, startTokenForNextFlush)) {
                     plot->incFlushesSinceLastUsed();
                 }

                 if constexpr (kDumpAtlasData) {
                     SkDebugf("%d ", plot->flushesSinceLastUsed());
                 }

                 // Count plots we can potentially upload to in all pages except the last one
                 // (the potential compactee).
                 if (plot->flushesSinceLastUsed() > kPlotRecentlyUsedCount) {
                     availablePlots.push_back() = plot;
                 }

                 plotIter.next();
             }

             if constexpr (kDumpAtlasData) {
                 SkDebugf("\n");
             }
         }

         // Count recently used plots in the last page and evict any that are no longer in use.
         // Since we prioritize uploading to the first pages, this will eventually
         // clear out usage of this page unless we have a large need.
         plotIter.init(fPages[lastPageIndex].fPlotList, PlotList::Iter::kHead_IterStart);
         unsigned int usedPlots = 0;
         if constexpr (kDumpAtlasData) {
             SkDebugf("page %d: ", lastPageIndex);
         }
         while (Plot* plot = plotIter.get()) {
             // Update number of flushes since plot was last used
             if (!plot->lastUseToken().inInterval(fPrevFlushToken, startTokenForNextFlush)) {
                 plot->incFlushesSinceLastUsed();
             }

             if constexpr (kDumpAtlasData) {
                 SkDebugf("%d ", plot->flushesSinceLastUsed());
             }

             // If this plot was used recently
             if (plot->flushesSinceLastUsed() <= kPlotRecentlyUsedCount) {
                 usedPlots++;
             } else if (plot->lastUseToken() != DrawToken::AlreadyFlushedToken()) {
                 // otherwise if aged out just evict it.
                 this->processEvictionAndResetRects(plot);
             }
             plotIter.next();
         }

         if constexpr (kDumpAtlasData) {
             SkDebugf("\n");
         }

         // If recently used plots in the last page are using less than a quarter of the page, try
         // to evict them if there's available space in lower index pages. Since we prioritize
         // uploading to the first pages, this will eventually clear out usage of this page unless
         // we have a large need.
         if (availablePlots.count() && usedPlots && usedPlots <= fNumPlots / 4) {
             plotIter.init(fPages[lastPageIndex].fPlotList, PlotList::Iter::kHead_IterStart);
             while (Plot* plot = plotIter.get()) {
                 // If this plot was used recently
                 if (plot->flushesSinceLastUsed() <= kPlotRecentlyUsedCount) {
                     // See if there's room in an lower index page and if so evict.
                     // We need to be somewhat harsh here so that a handful of plots that are
                     // consistently in use don't end up locking the page in memory.
                     if (availablePlots.count() > 0) {
                         this->processEvictionAndResetRects(plot);
                         this->processEvictionAndResetRects(availablePlots.back());
                         availablePlots.pop_back();
                         --usedPlots;
                     }
                     if (!usedPlots || !availablePlots.count()) {
                         break;
                     }
                 }
                 plotIter.next();
             }
         }

         // If none of the plots in the last page have been used recently, delete it.
         if (!usedPlots) {
             if constexpr (kDumpAtlasData) {
                 SkDebugf("delete %d\n", fNumActivePages-1);
             }

             this->deactivateLastPage();
             fFlushesSinceLastUse = 0;
         }
     }

     fPrevFlushToken = startTokenForNextFlush;
 }

 bool DrawAtlas::createPages(AtlasGenerationCounter* generationCounter) {
     SkASSERT(SkIsPow2(fTextureWidth) && SkIsPow2(fTextureHeight));

     int numPlotsX = fTextureWidth/fPlotWidth;
     int numPlotsY = fTextureHeight/fPlotHeight;

     for (uint32_t i = 0; i < this->maxPages(); ++i) {
         // Proxies are uncreated at first
         fProxies[i] = nullptr;

         // set up allocated plots
         fPages[i].fPlotArray = std::make_unique<sk_sp<Plot>[]>(numPlotsX * numPlotsY);

         sk_sp<Plot>* currPlot = fPages[i].fPlotArray.get();
         for (int y = numPlotsY - 1, r = 0; y >= 0; --y, ++r) {
             for (int x = numPlotsX - 1, c = 0; x >= 0; --x, ++c) {
                 uint32_t plotIndex = r * numPlotsX + c;
                 currPlot->reset(new Plot(
                     i, plotIndex, generationCounter, x, y, fPlotWidth, fPlotHeight, fColorType,
                     fBytesPerPixel));

                 // build LRU list
                 fPages[i].fPlotList.addToHead(currPlot->get());
                 ++currPlot;
             }
         }

     }

     return true;
 }

 bool DrawAtlas::activateNewPage(Recorder* recorder) {
     SkASSERT(fNumActivePages < this->maxPages());
     SkASSERT(!fProxies[fNumActivePages]);

     auto textureInfo = recorder->priv().caps()->getDefaultSampledTextureInfo(fColorType,
                                                                              /*levelCount=*/1,
                                                                              Protected::kNo,
                                                                              Renderable::kNo);
     fProxies[fNumActivePages].reset(new TextureProxy({fTextureWidth, fTextureHeight}, textureInfo,
                                                      SkBudgeted::kYes));
     if (!fProxies[fNumActivePages]) {
         return false;
     }

     if constexpr (kDumpAtlasData) {
         SkDebugf("activated page#: %d\n", fNumActivePages);
     }

     ++fNumActivePages;
     return true;
 }

 inline void DrawAtlas::deactivateLastPage() {
     SkASSERT(fNumActivePages);

     uint32_t lastPageIndex = fNumActivePages - 1;

     int numPlotsX = fTextureWidth/fPlotWidth;
     int numPlotsY = fTextureHeight/fPlotHeight;

     fPages[lastPageIndex].fPlotList.reset();
     for (int r = 0; r < numPlotsY; ++r) {
         for (int c = 0; c < numPlotsX; ++c) {
             uint32_t plotIndex = r * numPlotsX + c;

             Plot* currPlot = fPages[lastPageIndex].fPlotArray[plotIndex].get();
             currPlot->resetRects();
             currPlot->resetFlushesSinceLastUsed();

             // rebuild the LRU list
             SkDEBUGCODE(currPlot->resetListPtrs());
             fPages[lastPageIndex].fPlotList.addToHead(currPlot);
         }
     }

     // remove ref to the texture proxy
     fProxies[lastPageIndex].reset();
     --fNumActivePages;
 }

 void DrawAtlas::evictAllPlots() {
     PlotList::Iter plotIter;
     for (uint32_t pageIndex = 0; pageIndex < fNumActivePages; ++pageIndex) {
         plotIter.init(fPages[pageIndex].fPlotList, PlotList::Iter::kHead_IterStart);
         while (Plot* plot = plotIter.get()) {
             this->processEvictionAndResetRects(plot);
             plotIter.next();
         }
     }
 }

 DrawAtlasConfig::DrawAtlasConfig(int maxTextureSize, size_t maxBytes) {
     static const SkISize kARGBDimensions[] = {
         {256, 256},   // maxBytes < 2^19
         {512, 256},   // 2^19 <= maxBytes < 2^20
         {512, 512},   // 2^20 <= maxBytes < 2^21
         {1024, 512},  // 2^21 <= maxBytes < 2^22
         {1024, 1024}, // 2^22 <= maxBytes < 2^23
         {2048, 1024}, // 2^23 <= maxBytes
     };

     // Index 0 corresponds to maxBytes of 2^18, so start by dividing it by that
     maxBytes >>= 18;
     // Take the floor of the log to get the index
     int index = maxBytes > 0
         ? SkTPin<int>(SkPrevLog2(maxBytes), 0, std::size(kARGBDimensions) - 1)
         : 0;

     SkASSERT(kARGBDimensions[index].width() <= kMaxAtlasDim);
     SkASSERT(kARGBDimensions[index].height() <= kMaxAtlasDim);
     fARGBDimensions.set(std::min<int>(kARGBDimensions[index].width(), maxTextureSize),
                         std::min<int>(kARGBDimensions[index].height(), maxTextureSize));
     fMaxTextureSize = std::min<int>(maxTextureSize, kMaxAtlasDim);
 }

 SkISize DrawAtlasConfig::atlasDimensions(MaskFormat type) const {
     if (MaskFormat::kA8 == type) {
         // A8 is always 2x the ARGB dimensions, clamped to the max allowed texture size
         return { std::min<int>(2 * fARGBDimensions.width(), fMaxTextureSize),
                  std::min<int>(2 * fARGBDimensions.height(), fMaxTextureSize) };
     } else {
         return fARGBDimensions;
     }
 }

 SkISize DrawAtlasConfig::plotDimensions(MaskFormat type) const {
     if (MaskFormat::kA8 == type) {
         SkISize atlasDimensions = this->atlasDimensions(type);
         // For A8 we want to grow the plots at larger texture sizes to accept more of the
         // larger SDF glyphs. Since the largest SDF glyph can be 170x170 with padding, this
         // allows us to pack 3 in a 512x256 plot, or 9 in a 512x512 plot.

         // This will give us 512x256 plots for 2048x1024, 512x512 plots for 2048x2048,
         // and 256x256 plots otherwise.
         int plotWidth = atlasDimensions.width() >= 2048 ? 512 : 256;
         int plotHeight = atlasDimensions.height() >= 2048 ? 512 : 256;

         return { plotWidth, plotHeight };
     } else {
         // ARGB and LCD always use 256x256 plots -- this has been shown to be faster
         return { 256, 256 };
     }
 }

 }  // namespace skgpu::graphite
	/*
	* Copyright 2022 Google LLC
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "src/gpu/graphite/DrawAtlas.h"

	#include <memory>

	#include "include/gpu/graphite/Recorder.h"
	#include "include/private/SkTPin.h"
	#include "src/core/SkMathPriv.h"
	#include "src/core/SkOpts.h"
	#include "src/core/SkTraceEvent.h"
	#include "src/gpu/AtlasTypes.h"
	#include "src/gpu/graphite/Caps.h"
	#include "src/gpu/graphite/CommandTypes.h"
	#include "src/gpu/graphite/DrawContext.h"
	#include "src/gpu/graphite/RecorderPriv.h"
	#include "src/gpu/graphite/TextureProxy.h"

	namespace skgpu::graphite {

	#if defined(DUMP_ATLAS_DATA)
	static const constexpr bool kDumpAtlasData = true;
	#else
	static const constexpr bool kDumpAtlasData = false;
	#endif

	#ifdef SK_DEBUG
	void DrawAtlas::validate(const AtlasLocator& atlasLocator) const {
	// Verify that the plotIndex stored in the PlotLocator is consistent with the glyph rectangle
	int numPlotsX = fTextureWidth / fPlotWidth;
	int numPlotsY = fTextureHeight / fPlotHeight;

	int plotIndex = atlasLocator.plotIndex();
	auto topLeft = atlasLocator.topLeft();
	int plotX = topLeft.x() / fPlotWidth;
	int plotY = topLeft.y() / fPlotHeight;
	SkASSERT(plotIndex == (numPlotsY - plotY - 1) * numPlotsX + (numPlotsX - plotX - 1));
	}
	#endif

	std::unique_ptr<DrawAtlas> DrawAtlas::Make(SkColorType colorType, size_t bpp, int width,
	int height, int plotWidth, int plotHeight,
	AtlasGenerationCounter* generationCounter,
	AllowMultitexturing allowMultitexturing,
	PlotEvictionCallback* evictor,
	std::string_view label) {
	std::unique_ptr<DrawAtlas> atlas(new DrawAtlas(colorType, bpp, width, height,
	plotWidth, plotHeight, generationCounter,
	allowMultitexturing, label));

	if (evictor != nullptr) {
	atlas->fEvictionCallbacks.emplace_back(evictor);
	}
	return atlas;
	}

	///////////////////////////////////////////////////////////////////////////////

	DrawAtlas::DrawAtlas(SkColorType colorType, size_t bpp, int width, int height,
	int plotWidth, int plotHeight, AtlasGenerationCounter* generationCounter,
	AllowMultitexturing allowMultitexturing, std::string_view label)
	: fColorType(colorType)
	, fBytesPerPixel(bpp)
	, fTextureWidth(width)
	, fTextureHeight(height)
	, fPlotWidth(plotWidth)
	, fPlotHeight(plotHeight)
	, fLabel(label)
	, fGenerationCounter(generationCounter)
	, fAtlasGeneration(fGenerationCounter->next())
	, fPrevFlushToken(DrawToken::AlreadyFlushedToken())
	, fFlushesSinceLastUse(0)
	, fMaxPages(AllowMultitexturing::kYes == allowMultitexturing ?
	PlotLocator::kMaxMultitexturePages : 1)
	, fNumActivePages(0) {
	int numPlotsX = width/plotWidth;
	int numPlotsY = height/plotHeight;
	SkASSERT(numPlotsX * numPlotsY <= PlotLocator::kMaxPlots);
	SkASSERT(fPlotWidth * numPlotsX == fTextureWidth);
	SkASSERT(fPlotHeight * numPlotsY == fTextureHeight);

	fNumPlots = numPlotsX * numPlotsY;

	this->createPages(generationCounter);
	}

	inline void DrawAtlas::processEviction(PlotLocator plotLocator) {
	for (PlotEvictionCallback* evictor : fEvictionCallbacks) {
	evictor->evict(plotLocator);
	}

	fAtlasGeneration = fGenerationCounter->next();
	}

	inline bool DrawAtlas::updatePlot(AtlasLocator* atlasLocator, Plot* plot) {
	int pageIdx = plot->pageIndex();
	this->makeMRU(plot, pageIdx);

	// The actual upload will be created in recordUploads().

	atlasLocator->updatePlotLocator(plot->plotLocator());
	SkDEBUGCODE(this->validate(*atlasLocator);)
	return true;
	}

	bool DrawAtlas::addToPage(unsigned int pageIdx, int width, int height, const void* image,
	AtlasLocator* atlasLocator) {
	SkASSERT(fProxies[pageIdx]);

	// look through all allocated plots for one we can share, in Most Recently Refed order
	PlotList::Iter plotIter;
	plotIter.init(fPages[pageIdx].fPlotList, PlotList::Iter::kHead_IterStart);

	for (Plot* plot = plotIter.get(); plot; plot = plotIter.next()) {
	if (plot->addSubImage(width, height, image, atlasLocator)) {
	return this->updatePlot(atlasLocator, plot);
	}
	}

	return false;
	}

	bool DrawAtlas::recordUploads(DrawContext* dc, Recorder* recorder) {
	TRACE_EVENT0("skia.gpu", TRACE_FUNC);
	for (uint32_t pageIdx = 0; pageIdx < fNumActivePages; ++pageIdx) {
	PlotList::Iter plotIter;
	plotIter.init(fPages[pageIdx].fPlotList, PlotList::Iter::kHead_IterStart);
	for (Plot* plot = plotIter.get(); plot; plot = plotIter.next()) {
	if (plot->needsUpload()) {
	TextureProxy* proxy = fProxies[pageIdx].get();
	SkASSERT(proxy);

	const void* dataPtr;
	SkIRect dstRect;
	std::tie(dataPtr, dstRect) = plot->prepareForUpload();

	std::vector<MipLevel> levels;
	levels.push_back({dataPtr, fBytesPerPixel*fPlotWidth});

	if (!dc->recordUpload(recorder, sk_ref_sp(proxy), fColorType, levels, dstRect)) {
	return false;
	}
	}
	}
	}
	return true;
	}

	// Number of atlas-related flushes beyond which we consider a plot to no longer be in use.
	//
	// This value is somewhat arbitrary -- the idea is to keep it low enough that
	// a page with unused plots will get removed reasonably quickly, but allow it
	// to hang around for a bit in case it's needed. The assumption is that flushes
	// are rare; i.e., we are not continually refreshing the frame.
	static constexpr auto kPlotRecentlyUsedCount = 32;
	static constexpr auto kAtlasRecentlyUsedCount = 128;

	DrawAtlas::ErrorCode DrawAtlas::addToAtlas(Recorder* recorder,
	int width, int height, const void* image,
	AtlasLocator* atlasLocator) {
	if (width > fPlotWidth \|\| height > fPlotHeight) {
	return ErrorCode::kError;
	}

	// Look through each page to see if we can upload without having to flush
	// We prioritize this upload to the first pages, not the most recently used, to make it easier
	// to remove unused pages in reverse page order.
	for (unsigned int pageIdx = 0; pageIdx < fNumActivePages; ++pageIdx) {
	if (this->addToPage(pageIdx, width, height, image, atlasLocator)) {
	return ErrorCode::kSucceeded;
	}
	}

	// If the above fails, then see if the least recently used plot per page has already been
	// queued for upload if we're at max page allocation, or if the plot has aged out otherwise.
	// We wait until we've grown to the full number of pages to begin evicting already queued
	// plots so that we can maximize the opportunity for reuse.
	// As before we prioritize this upload to the first pages, not the most recently used.
	if (fNumActivePages == this->maxPages()) {
	for (unsigned int pageIdx = 0; pageIdx < fNumActivePages; ++pageIdx) {
	Plot* plot = fPages[pageIdx].fPlotList.tail();
	SkASSERT(plot);
	if (plot->lastUseToken() < recorder->priv().tokenTracker()->nextTokenToFlush()) {
	this->processEvictionAndResetRects(plot);
	SkDEBUGCODE(bool verify = )plot->addSubImage(width, height, image, atlasLocator);
	SkASSERT(verify);
	if (!this->updatePlot(atlasLocator, plot)) {
	return ErrorCode::kError;
	}
	return ErrorCode::kSucceeded;
	}
	}
	} else {
	// If we haven't activated all the available pages, try to create a new one and add to it
	if (!this->activateNewPage(recorder)) {
	return ErrorCode::kError;
	}

	if (this->addToPage(fNumActivePages-1, width, height, image, atlasLocator)) {
	return ErrorCode::kSucceeded;
	} else {
	// If we fail to upload to a newly activated page then something has gone terribly
	// wrong - return an error
	return ErrorCode::kError;
	}
	}

	if (!fNumActivePages) {
	return ErrorCode::kError;
	}

	// All plots are currently in use by the current set of draws, so we need to fail. This
	// gives the Device a chance to snap the current set of uploads and draws, advance the draw
	// token, and call back into this function. The subsequent call will have plots available
	// for fresh uploads.
	return ErrorCode::kTryAgain;
	}

	void DrawAtlas::compact(DrawToken startTokenForNextFlush) {
	if (fNumActivePages < 1) {
	fPrevFlushToken = startTokenForNextFlush;
	return;
	}

	// For all plots, reset number of flushes since used if used this frame.
	PlotList::Iter plotIter;
	bool atlasUsedThisFlush = false;
	for (uint32_t pageIndex = 0; pageIndex < fNumActivePages; ++pageIndex) {
	plotIter.init(fPages[pageIndex].fPlotList, PlotList::Iter::kHead_IterStart);
	while (Plot* plot = plotIter.get()) {
	// Reset number of flushes since used
	if (plot->lastUseToken().inInterval(fPrevFlushToken, startTokenForNextFlush)) {
	plot->resetFlushesSinceLastUsed();
	atlasUsedThisFlush = true;
	}

	plotIter.next();
	}
	}

	if (atlasUsedThisFlush) {
	fFlushesSinceLastUse = 0;
	} else {
	++fFlushesSinceLastUse;
	}

	// We only try to compact if the atlas was used in the recently completed flush or
	// hasn't been used in a long time.
	// This is to handle the case where a lot of text or path rendering has occurred but then just
	// a blinking cursor is drawn.
	if (atlasUsedThisFlush \|\| fFlushesSinceLastUse > kAtlasRecentlyUsedCount) {
	SkTArray<Plot*> availablePlots;
	uint32_t lastPageIndex = fNumActivePages - 1;

	// For all plots but the last one, update number of flushes since used, and check to see
	// if there are any in the first pages that the last page can safely upload to.
	for (uint32_t pageIndex = 0; pageIndex < lastPageIndex; ++pageIndex) {
	if constexpr (kDumpAtlasData) {
	SkDebugf("page %d: ", pageIndex);
	}

	plotIter.init(fPages[pageIndex].fPlotList, PlotList::Iter::kHead_IterStart);
	while (Plot* plot = plotIter.get()) {
	// Update number of flushes since plot was last used
	// We only increment the 'sinceLastUsed' count for flushes where the atlas was used
	// to avoid deleting everything when we return to text drawing in the blinking
	// cursor case
	if (!plot->lastUseToken().inInterval(fPrevFlushToken, startTokenForNextFlush)) {
	plot->incFlushesSinceLastUsed();
	}

	if constexpr (kDumpAtlasData) {
	SkDebugf("%d ", plot->flushesSinceLastUsed());
	}

	// Count plots we can potentially upload to in all pages except the last one
	// (the potential compactee).
	if (plot->flushesSinceLastUsed() > kPlotRecentlyUsedCount) {
	availablePlots.push_back() = plot;
	}

	plotIter.next();
	}

	if constexpr (kDumpAtlasData) {
	SkDebugf("\n");
	}
	}

	// Count recently used plots in the last page and evict any that are no longer in use.
	// Since we prioritize uploading to the first pages, this will eventually
	// clear out usage of this page unless we have a large need.
	plotIter.init(fPages[lastPageIndex].fPlotList, PlotList::Iter::kHead_IterStart);
	unsigned int usedPlots = 0;
	if constexpr (kDumpAtlasData) {
	SkDebugf("page %d: ", lastPageIndex);
	}
	while (Plot* plot = plotIter.get()) {
	// Update number of flushes since plot was last used
	if (!plot->lastUseToken().inInterval(fPrevFlushToken, startTokenForNextFlush)) {
	plot->incFlushesSinceLastUsed();
	}

	if constexpr (kDumpAtlasData) {
	SkDebugf("%d ", plot->flushesSinceLastUsed());
	}

	// If this plot was used recently
	if (plot->flushesSinceLastUsed() <= kPlotRecentlyUsedCount) {
	usedPlots++;
	} else if (plot->lastUseToken() != DrawToken::AlreadyFlushedToken()) {
	// otherwise if aged out just evict it.
	this->processEvictionAndResetRects(plot);
	}
	plotIter.next();
	}

	if constexpr (kDumpAtlasData) {
	SkDebugf("\n");
	}

	// If recently used plots in the last page are using less than a quarter of the page, try
	// to evict them if there's available space in lower index pages. Since we prioritize
	// uploading to the first pages, this will eventually clear out usage of this page unless
	// we have a large need.
	if (availablePlots.count() && usedPlots && usedPlots <= fNumPlots / 4) {
	plotIter.init(fPages[lastPageIndex].fPlotList, PlotList::Iter::kHead_IterStart);
	while (Plot* plot = plotIter.get()) {
	// If this plot was used recently
	if (plot->flushesSinceLastUsed() <= kPlotRecentlyUsedCount) {
	// See if there's room in an lower index page and if so evict.
	// We need to be somewhat harsh here so that a handful of plots that are
	// consistently in use don't end up locking the page in memory.
	if (availablePlots.count() > 0) {
	this->processEvictionAndResetRects(plot);
	this->processEvictionAndResetRects(availablePlots.back());
	availablePlots.pop_back();
	--usedPlots;
	}
	if (!usedPlots \|\| !availablePlots.count()) {
	break;
	}
	}
	plotIter.next();
	}
	}

	// If none of the plots in the last page have been used recently, delete it.
	if (!usedPlots) {
	if constexpr (kDumpAtlasData) {
	SkDebugf("delete %d\n", fNumActivePages-1);
	}

	this->deactivateLastPage();
	fFlushesSinceLastUse = 0;
	}
	}

	fPrevFlushToken = startTokenForNextFlush;
	}

	bool DrawAtlas::createPages(AtlasGenerationCounter* generationCounter) {
	SkASSERT(SkIsPow2(fTextureWidth) && SkIsPow2(fTextureHeight));

	int numPlotsX = fTextureWidth/fPlotWidth;
	int numPlotsY = fTextureHeight/fPlotHeight;

	for (uint32_t i = 0; i < this->maxPages(); ++i) {
	// Proxies are uncreated at first
	fProxies[i] = nullptr;

	// set up allocated plots
	fPages[i].fPlotArray = std::make_unique<sk_sp<Plot>[]>(numPlotsX * numPlotsY);

	sk_sp<Plot>* currPlot = fPages[i].fPlotArray.get();
	for (int y = numPlotsY - 1, r = 0; y >= 0; --y, ++r) {
	for (int x = numPlotsX - 1, c = 0; x >= 0; --x, ++c) {
	uint32_t plotIndex = r * numPlotsX + c;
	currPlot->reset(new Plot(
	i, plotIndex, generationCounter, x, y, fPlotWidth, fPlotHeight, fColorType,
	fBytesPerPixel));

	// build LRU list
	fPages[i].fPlotList.addToHead(currPlot->get());
	++currPlot;
	}
	}

	}

	return true;
	}

	bool DrawAtlas::activateNewPage(Recorder* recorder) {
	SkASSERT(fNumActivePages < this->maxPages());
	SkASSERT(!fProxies[fNumActivePages]);

	auto textureInfo = recorder->priv().caps()->getDefaultSampledTextureInfo(fColorType,
	/levelCount=/1,
	Protected::kNo,
	Renderable::kNo);
	fProxies[fNumActivePages].reset(new TextureProxy({fTextureWidth, fTextureHeight}, textureInfo,
	SkBudgeted::kYes));
	if (!fProxies[fNumActivePages]) {
	return false;
	}

	if constexpr (kDumpAtlasData) {
	SkDebugf("activated page#: %d\n", fNumActivePages);
	}

	++fNumActivePages;
	return true;
	}

	inline void DrawAtlas::deactivateLastPage() {
	SkASSERT(fNumActivePages);

	uint32_t lastPageIndex = fNumActivePages - 1;

	int numPlotsX = fTextureWidth/fPlotWidth;
	int numPlotsY = fTextureHeight/fPlotHeight;

	fPages[lastPageIndex].fPlotList.reset();
	for (int r = 0; r < numPlotsY; ++r) {
	for (int c = 0; c < numPlotsX; ++c) {
	uint32_t plotIndex = r * numPlotsX + c;

	Plot* currPlot = fPages[lastPageIndex].fPlotArray[plotIndex].get();
	currPlot->resetRects();
	currPlot->resetFlushesSinceLastUsed();

	// rebuild the LRU list
	SkDEBUGCODE(currPlot->resetListPtrs());
	fPages[lastPageIndex].fPlotList.addToHead(currPlot);
	}
	}

	// remove ref to the texture proxy
	fProxies[lastPageIndex].reset();
	--fNumActivePages;
	}

	void DrawAtlas::evictAllPlots() {
	PlotList::Iter plotIter;
	for (uint32_t pageIndex = 0; pageIndex < fNumActivePages; ++pageIndex) {
	plotIter.init(fPages[pageIndex].fPlotList, PlotList::Iter::kHead_IterStart);
	while (Plot* plot = plotIter.get()) {
	this->processEvictionAndResetRects(plot);
	plotIter.next();
	}
	}
	}

	DrawAtlasConfig::DrawAtlasConfig(int maxTextureSize, size_t maxBytes) {
	static const SkISize kARGBDimensions[] = {
	{256, 256}, // maxBytes < 2^19
	{512, 256}, // 2^19 <= maxBytes < 2^20
	{512, 512}, // 2^20 <= maxBytes < 2^21
	{1024, 512}, // 2^21 <= maxBytes < 2^22
	{1024, 1024}, // 2^22 <= maxBytes < 2^23
	{2048, 1024}, // 2^23 <= maxBytes
	};

	// Index 0 corresponds to maxBytes of 2^18, so start by dividing it by that
	maxBytes >>= 18;
	// Take the floor of the log to get the index
	int index = maxBytes > 0
	? SkTPin<int>(SkPrevLog2(maxBytes), 0, std::size(kARGBDimensions) - 1)
	: 0;

	SkASSERT(kARGBDimensions[index].width() <= kMaxAtlasDim);
	SkASSERT(kARGBDimensions[index].height() <= kMaxAtlasDim);
	fARGBDimensions.set(std::min<int>(kARGBDimensions[index].width(), maxTextureSize),
	std::min<int>(kARGBDimensions[index].height(), maxTextureSize));
	fMaxTextureSize = std::min<int>(maxTextureSize, kMaxAtlasDim);
	}

	SkISize DrawAtlasConfig::atlasDimensions(MaskFormat type) const {
	if (MaskFormat::kA8 == type) {
	// A8 is always 2x the ARGB dimensions, clamped to the max allowed texture size
	return { std::min<int>(2 * fARGBDimensions.width(), fMaxTextureSize),
	std::min<int>(2 * fARGBDimensions.height(), fMaxTextureSize) };
	} else {
	return fARGBDimensions;
	}
	}

	SkISize DrawAtlasConfig::plotDimensions(MaskFormat type) const {
	if (MaskFormat::kA8 == type) {
	SkISize atlasDimensions = this->atlasDimensions(type);
	// For A8 we want to grow the plots at larger texture sizes to accept more of the
	// larger SDF glyphs. Since the largest SDF glyph can be 170x170 with padding, this
	// allows us to pack 3 in a 512x256 plot, or 9 in a 512x512 plot.

	// This will give us 512x256 plots for 2048x1024, 512x512 plots for 2048x2048,
	// and 256x256 plots otherwise.
	int plotWidth = atlasDimensions.width() >= 2048 ? 512 : 256;
	int plotHeight = atlasDimensions.height() >= 2048 ? 512 : 256;

	return { plotWidth, plotHeight };
	} else {
	// ARGB and LCD always use 256x256 plots -- this has been shown to be faster
	return { 256, 256 };
	}
	}

	} // namespace skgpu::graphite