Added GrTextureStripAtlas object.

Review URL: https://codereview.appspot.com/6457099

git-svn-id: http://skia.googlecode.com/svn/trunk@5070 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
rileya@google.com 2012-08-13 20:28:48 +00:00
parent 1bd2d67702
commit 2e2aedc204
4 changed files with 486 additions and 0 deletions

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@ -311,6 +311,8 @@
'../src/gpu/gr_unittests.cpp',
'../src/gpu/effects/Gr1DKernelEffect.h',
'../src/gpu/effects/GrTextureStripAtlas.h',
'../src/gpu/effects/GrTextureStripAtlas.cpp',
'../src/gpu/effects/GrColorTableEffect.cpp',
'../src/gpu/effects/GrColorTableEffect.h',
'../src/gpu/effects/GrConvolutionEffect.cpp',

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@ -840,6 +840,7 @@ private:
// internal class would have only be callable in src/gpu. The facade would
// only have to functions necessary for clients.
friend class GrAtlas;
friend class GrTextureStripAtlas;
// Needed so GrTexture's returnToCache helper function can call
// addExistingTextureToCache

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@ -0,0 +1,320 @@
/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "GrTextureStripAtlas.h"
#include "SkPixelRef.h"
#include "SkTSearch.h"
#include "GrBinHashKey.h"
#include "GrTexture.h"
#ifdef SK_DEBUG
#define VALIDATE this->validate()
#else
#define VALIDATE
#endif
GR_DEFINE_RESOURCE_CACHE_DOMAIN(GrTextureStripAtlas, GetTextureStripAtlasDomain)
int32_t GrTextureStripAtlas::gCacheCount = 0;
// Hash table entry for atlases
class AtlasEntry;
typedef GrTBinHashKey<AtlasEntry, sizeof(GrTextureStripAtlas::Desc)> AtlasHashKey;
class AtlasEntry : public ::GrNoncopyable {
public:
AtlasEntry() : fAtlas(NULL) {}
~AtlasEntry() { SkDELETE(fAtlas); }
int compare(const AtlasHashKey& key) const { return fKey.compare(key); }
AtlasHashKey fKey;
GrTextureStripAtlas* fAtlas;
};
// Ugly way of ensuring that we clean up the atlases on exit
struct AtlasEntries {
~AtlasEntries() { fEntries.deleteAll(); }
SkTDArray<AtlasEntry*> fEntries;
};
GrTextureStripAtlas* GrTextureStripAtlas::GetAtlas(const GrTextureStripAtlas::Desc& desc) {
static AtlasEntries gAtlasEntries;
static GrTHashTable<AtlasEntry, AtlasHashKey, 8> gAtlasCache;
AtlasHashKey key;
key.setKeyData(desc.asKey());
AtlasEntry* entry = gAtlasCache.find(key);
if (NULL != entry) {
return entry->fAtlas;
} else {
entry = SkNEW(AtlasEntry);
gAtlasEntries.fEntries.push(entry);
entry->fAtlas = SkNEW_ARGS(GrTextureStripAtlas, (desc));
entry->fKey = key;
gAtlasCache.insert(key, entry);
return entry->fAtlas;
}
}
GrTextureStripAtlas::GrTextureStripAtlas(GrTextureStripAtlas::Desc desc)
: fCacheID(kCacheDomain + sk_atomic_inc(&gCacheCount))
, fLockedRows(0)
, fDesc(desc)
, fNumRows(desc.fHeight / desc.fRowHeight)
, fRows(SkNEW_ARRAY(AtlasRow, fNumRows))
, fLRUFront(NULL)
, fLRUBack(NULL) {
GrAssert(fNumRows * fDesc.fRowHeight == fDesc.fHeight);
this->initLRU();
VALIDATE;
}
GrTextureStripAtlas::~GrTextureStripAtlas() {
SkDELETE_ARRAY(fRows);
}
int GrTextureStripAtlas::lockRow(const SkBitmap& data) {
VALIDATE;
if (0 == fLockedRows) {
this->lockTexture();
}
int key = data.getGenerationID();
int rowNumber = -1;
int index = this->searchByKey(key);
if (index >= 0) {
// We already have the data in a row, so we can just return that row
AtlasRow* row = fKeyTable[index];
if (0 == row->fLocks) {
this->removeFromLRU(row);
}
++row->fLocks;
// Since all the rows are always stored in a contiguous array, we can save the memory
// required for storing row numbers and just compute it with some pointer arithmetic
rowNumber = static_cast<int>(row - fRows);
} else {
// ~index is the index where we will insert the new key to keep things sorted
index = ~index;
// We don't have this data cached, so pick the least recently used row to copy into
AtlasRow* row = this->getLRU();
if (NULL == row) {
// force a flush, which should unlock all the rows; then try again
fDesc.fContext->flush();
row = this->getLRU();
if (NULL == row) {
return -1;
}
}
this->removeFromLRU(row);
uint32_t oldKey = row->fKey;
row->fKey = key;
row->fLocks = 1;
// If we are writing into a row that already held bitmap data, we need to remove the
// reference to that genID which is stored in our sorted table of key values.
if (oldKey != kEmptyAtlasRowKey) {
// Find the entry in the list; if it's before the index where we plan on adding the new
// entry, we decrement since it will shift elements ahead of it back by one.
int oldIndex = this->searchByKey(oldKey);
if (oldIndex <= index) {
--index;
}
fKeyTable.remove(oldIndex);
}
fKeyTable.insert(index, 1, &row);
rowNumber = static_cast<int>(row - fRows);
SkAutoLockPixels lock(data);
// Pass in the kDontFlush flag, since we know we're writing to a part of this texture
// that is not currently in use
fDesc.fContext->internalWriteTexturePixels(fEntry.texture(), 0,
rowNumber * fDesc.fRowHeight,
fDesc.fWidth,
fDesc.fRowHeight,
SkBitmapConfig2GrPixelConfig(data.config()),
data.getPixels(), data.rowBytes(),
GrContext::kDontFlush_PixelOpsFlag);
}
++fLockedRows;
GrAssert(rowNumber >= 0);
VALIDATE;
return rowNumber;
}
void GrTextureStripAtlas::unlockRow(int row) {
VALIDATE;
--fRows[row].fLocks;
--fLockedRows;
GrAssert(fRows[row].fLocks >= 0 && fLockedRows >= 0);
if (0 == fRows[row].fLocks) {
this->appendLRU(fRows + row);
}
if (0 == fLockedRows) {
this->unlockTexture();
}
VALIDATE;
}
GrTextureStripAtlas::AtlasRow* GrTextureStripAtlas::getLRU() {
// Front is least-recently-used
AtlasRow* row = fLRUFront;
return row;
}
void GrTextureStripAtlas::lockTexture() {
GrTextureParams params;
GrTextureDesc texDesc;
texDesc.fWidth = fDesc.fWidth;
texDesc.fHeight = fDesc.fHeight;
texDesc.fConfig = fDesc.fConfig;
GrCacheData cacheData(fCacheID);
cacheData.fResourceDomain = GetTextureStripAtlasDomain();
fEntry = fDesc.fContext->findAndLockTexture(texDesc, cacheData, &params);
if (NULL == fEntry.texture()) {
fEntry = fDesc.fContext->createAndLockTexture(&params, texDesc, cacheData, NULL, 0);
// This is a new texture, so all of our cache info is now invalid
this->initLRU();
fKeyTable.rewind();
}
GrAssert(NULL != fEntry.texture());
}
void GrTextureStripAtlas::unlockTexture() {
GrAssert(NULL != fEntry.texture() && 0 == fLockedRows);
fDesc.fContext->unlockTexture(fEntry);
fEntry.reset();
}
void GrTextureStripAtlas::initLRU() {
fLRUFront = NULL;
fLRUBack = NULL;
// Initially all the rows are in the LRU list
for (int i = 0; i < fNumRows; ++i) {
fRows[i].fKey = kEmptyAtlasRowKey;
fRows[i].fNext = NULL;
fRows[i].fPrev = NULL;
this->appendLRU(fRows + i);
}
GrAssert(NULL == fLRUFront->fPrev && NULL == fLRUBack->fNext);
}
void GrTextureStripAtlas::appendLRU(AtlasRow* row) {
GrAssert(NULL == row->fPrev && NULL == row->fNext);
if (NULL == fLRUFront && NULL == fLRUBack) {
fLRUFront = row;
fLRUBack = row;
} else {
row->fPrev = fLRUBack;
fLRUBack->fNext = row;
fLRUBack = row;
}
}
void GrTextureStripAtlas::removeFromLRU(AtlasRow* row) {
GrAssert(NULL != row);
if (NULL != row->fNext && NULL != row->fPrev) {
row->fPrev->fNext = row->fNext;
row->fNext->fPrev = row->fPrev;
} else {
if (NULL == row->fNext) {
GrAssert(row == fLRUBack);
fLRUBack = row->fPrev;
fLRUBack->fNext = NULL;
}
if (NULL == row->fPrev) {
GrAssert(row == fLRUFront);
fLRUFront = row->fNext;
fLRUFront->fPrev = NULL;
}
}
row->fNext = NULL;
row->fPrev = NULL;
}
int GrTextureStripAtlas::searchByKey(uint32_t key) {
AtlasRow target;
target.fKey = key;
return SkTSearch<AtlasRow, GrTextureStripAtlas::compareKeys>((const AtlasRow**)fKeyTable.begin(),
fKeyTable.count(),
&target,
sizeof(AtlasRow*));
}
#ifdef SK_DEBUG
void GrTextureStripAtlas::validate() {
// Our key table should be sorted
uint32_t prev = 1 > fKeyTable.count() ? 0 : fKeyTable[0]->fKey;
for (int i = 1; i < fKeyTable.count(); ++i) {
GrAssert(prev < fKeyTable[i]->fKey);
GrAssert(fKeyTable[i]->fKey != kEmptyAtlasRowKey);
prev = fKeyTable[i]->fKey;
}
int lruCount = 0;
// Validate LRU pointers, and count LRU entries
GrAssert(NULL == fLRUFront || NULL == fLRUFront->fPrev);
GrAssert(NULL == fLRUBack || NULL == fLRUBack->fNext);
for (AtlasRow* r = fLRUFront; r != NULL; r = r->fNext) {
if (NULL == r->fNext) {
GrAssert(r == fLRUBack);
} else {
GrAssert(r->fNext->fPrev == r);
}
++lruCount;
}
int rowLocks = 0;
int freeRows = 0;
for (int i = 0; i < fNumRows; ++i) {
rowLocks += fRows[i].fLocks;
if (0 == fRows[i].fLocks) {
++freeRows;
bool inLRU = false;
// Step through the LRU and make sure it's present
for (AtlasRow* r = fLRUFront; r != NULL; r = r->fNext) {
if (r == &fRows[i]) {
inLRU = true;
break;
}
}
GrAssert(inLRU);
} else {
// If we are locked, we should have a key
GrAssert(kEmptyAtlasRowKey != fRows[i].fKey);
}
// If we have a key != kEmptyAtlasRowKey, it should be in the key table
GrAssert(fRows[i].fKey == kEmptyAtlasRowKey || this->searchByKey(fRows[i].fKey) >= 0);
}
// Our count of locks should equal the sum of row locks
GrAssert(rowLocks == fLockedRows);
// We should have one lru entry for each free row
GrAssert(freeRows == lruCount);
// If we have locked rows, we should have a locked texture, otherwise
// it should be unlocked
if (fLockedRows == 0) {
GrAssert(NULL == fEntry.texture());
} else {
GrAssert(NULL != fEntry.texture());
}
}
#endif

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@ -0,0 +1,163 @@
/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrTextureStripAtlas_DEFINED
#define GrTextureStripAtlas_DEFINED
#include "SkBitmap.h"
#include "GrTHashCache.h"
#include "SkGr.h"
#include "SkTDArray.h"
/**
* Maintains a single large texture whose rows store many textures of a small fixed height,
* stored in rows across the x-axis such that we can safely wrap/repeat them horizontally.
*/
class GrTextureStripAtlas {
public:
GR_DECLARE_RESOURCE_CACHE_DOMAIN(GetTextureStripAtlasDomain)
/**
* Descriptor struct which we'll use as a hash table key
**/
struct Desc {
Desc() { memset(this, 0, sizeof(*this)); }
uint16_t fWidth, fHeight, fRowHeight;
GrPixelConfig fConfig;
GrContext* fContext;
const uint32_t* asKey() const { return reinterpret_cast<const uint32_t*>(this); }
};
/**
* Try to find an atlas with the required parameters, creates a new one if necessary
*/
static GrTextureStripAtlas* GetAtlas(const Desc& desc);
~GrTextureStripAtlas();
/**
* Add a texture to the atlas
* @param data Bitmap data to copy into the row
* @return The row index we inserted into, or -1 if we failed to find an open row. The caller
* is responsible for calling unlockRow() with this row index when it's done with it.
*/
int lockRow(const SkBitmap& data);
void unlockRow(int row);
/**
* These functions help turn an integer row index in [0, 1, 2, ... numRows] into a scalar y
* texture coordinate in [0, 1] that we can use in a shader.
*
* If a regular texture access without using the atlas looks like:
*
* texture2D(sampler, vec2(x, y))
*
* Then when using the atlas we'd replace it with:
*
* texture2D(sampler, vec2(x, yOffset + y * scaleFactor))
*
* Where yOffset, returned by getYOffset(), is the offset to the start of the row within the
* atlas and scaleFactor, returned by getVerticalScaleFactor(), is the y-scale of the row,
* relative to the height of the overall atlas texture.
*/
GrScalar getYOffset(int row) const { return SkIntToScalar(row) / fNumRows; }
GrScalar getVerticalScaleFactor() const { return SkIntToScalar(fDesc.fRowHeight) / fDesc.fHeight; }
GrContext* getContext() const { return fDesc.fContext; }
GrTexture* getTexture() const { return fEntry.texture(); }
private:
// Key to indicate an atlas row without any meaningful data stored in it
const static uint32_t kEmptyAtlasRowKey = 0xffffffff;
/**
* The state of a single row in our cache, next/prev pointers allow these to be chained
* together to represent LRU status
*/
struct AtlasRow : public GrNoncopyable {
AtlasRow() : fKey(kEmptyAtlasRowKey), fLocks(0), fNext(NULL), fPrev(NULL) { }
// GenerationID of the bitmap that is represented by this row, 0xffffffff means "empty"
uint32_t fKey;
// How many times this has been locked (0 == unlocked)
int32_t fLocks;
// We maintain an LRU linked list between unlocked nodes with these pointers
AtlasRow* fNext;
AtlasRow* fPrev;
};
/**
* We'll only allow construction via the static GrTextureStripAtlas::GetAtlas
*/
GrTextureStripAtlas(Desc desc);
void lockTexture();
void unlockTexture();
/**
* Initialize our LRU list (if one already exists, clear it and start anew)
*/
void initLRU();
/**
* Grabs the least recently used free row out of the LRU list, returns NULL if no rows are free.
*/
AtlasRow* getLRU();
void appendLRU(AtlasRow* row);
void removeFromLRU(AtlasRow* row);
/**
* Searches the key table for a key and returns the index if found; if not found, it returns
* the bitwise not of the index at which we could insert the key to maintain a sorted list.
**/
int searchByKey(uint32_t key);
/**
* Compare two atlas rows by key, so we can sort/search by key
*/
static int compareKeys(const AtlasRow* lhs, const AtlasRow* rhs) {
return lhs->fKey - rhs->fKey;
}
#ifdef SK_DEBUG
void validate();
#endif
// We increment fCacheCount for each atlas, kCacheDomain is just an arbitrary number we add to
// it in hopes of preventing collisions (this is only until resource domains get worked out).
static int32_t gCacheCount;
static const uint64_t kCacheDomain = 0xfffffffffffffff0;
// A unique ID for this texture (formed with: kCacheDomain + gCacheCount++), so we can be sure
// that if we get a texture back from the texture cache, that it's the same one we last used.
const uint64_t fCacheID;
// Total locks on all rows (when this reaches zero, we can unlock our texture)
int32_t fLockedRows;
const Desc fDesc;
const uint16_t fNumRows;
GrContext::TextureCacheEntry fEntry;
// Array of AtlasRows which store the state of all our rows. Stored in a contiguous array, in
// order that they appear in our texture, this means we can subtract this pointer from a row
// pointer to get its index in the texture, and can save storing a row number in AtlasRow.
AtlasRow* fRows;
// Head and tail for linked list of least-recently-used rows (front = least recently used).
// Note that when a texture is locked, it gets removed from this list until it is unlocked.
AtlasRow* fLRUFront;
AtlasRow* fLRUBack;
// A list of pointers to AtlasRows that currently contain cached images, sorted by key
SkTDArray<AtlasRow*> fKeyTable;
};
#endif