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| 1 /* | |
| 2 * Copyright 2012 Google Inc. | |
| 3 * | |
| 4 * Use of this source code is governed by a BSD-style license that can be | |
| 5 * found in the LICENSE file. | |
| 6 */ | |
| 7 | |
| 8 #ifndef GrTextureStripAtlas_DEFINED | |
| 9 #define GrTextureStripAtlas_DEFINED | |
| 10 | |
| 11 #include "SkBitmap.h" | |
| 12 #include "SkOpts.h" | |
| 13 #include "SkGr.h" | |
| 14 #include "SkTDArray.h" | |
| 15 #include "SkTDynamicHash.h" | |
| 16 #include "SkTypes.h" | |
| 17 | |
| 18 /** | |
| 19 * Maintains a single large texture whose rows store many textures of a small fi
xed height, | |
| 20 * stored in rows across the x-axis such that we can safely wrap/repeat them hor
izontally. | |
| 21 */ | |
| 22 class GrTextureStripAtlas { | |
| 23 public: | |
| 24 /** | |
| 25 * Descriptor struct which we'll use as a hash table key | |
| 26 **/ | |
| 27 struct Desc { | |
| 28 Desc() { sk_bzero(this, sizeof(*this)); } | |
| 29 GrContext* fContext; | |
| 30 GrPixelConfig fConfig; | |
| 31 uint16_t fWidth, fHeight, fRowHeight; | |
| 32 uint16_t fUnusedPadding; | |
| 33 bool operator==(const Desc& other) const { | |
| 34 return 0 == memcmp(this, &other, sizeof(Desc)); | |
| 35 } | |
| 36 }; | |
| 37 | |
| 38 /** | |
| 39 * Try to find an atlas with the required parameters, creates a new one if n
ecessary | |
| 40 */ | |
| 41 static GrTextureStripAtlas* GetAtlas(const Desc& desc); | |
| 42 | |
| 43 ~GrTextureStripAtlas(); | |
| 44 | |
| 45 /** | |
| 46 * Add a texture to the atlas | |
| 47 * @param data Bitmap data to copy into the row | |
| 48 * @return The row index we inserted into, or -1 if we failed to find an op
en row. The caller | |
| 49 * is responsible for calling unlockRow() with this row index when it's
done with it. | |
| 50 */ | |
| 51 int lockRow(const SkBitmap& data); | |
| 52 void unlockRow(int row); | |
| 53 | |
| 54 /** | |
| 55 * These functions help turn an integer row index in [0, 1, 2, ... numRows]
into a scalar y | |
| 56 * texture coordinate in [0, 1] that we can use in a shader. | |
| 57 * | |
| 58 * If a regular texture access without using the atlas looks like: | |
| 59 * | |
| 60 * texture2D(sampler, vec2(x, y)) | |
| 61 * | |
| 62 * Then when using the atlas we'd replace it with: | |
| 63 * | |
| 64 * texture2D(sampler, vec2(x, yOffset + y * scaleFactor)) | |
| 65 * | |
| 66 * Where yOffset, returned by getYOffset(), is the offset to the start of th
e row within the | |
| 67 * atlas and scaleFactor, returned by getNormalizedTexelHeight, is the norma
lized height of | |
| 68 * one texel row. | |
| 69 */ | |
| 70 SkScalar getYOffset(int row) const { return SkIntToScalar(row) / fNumRows; } | |
| 71 SkScalar getNormalizedTexelHeight() const { return fNormalizedYHeight; } | |
| 72 | |
| 73 GrContext* getContext() const { return fDesc.fContext; } | |
| 74 GrTexture* getTexture() const { return fTexture; } | |
| 75 | |
| 76 private: | |
| 77 | |
| 78 // Key to indicate an atlas row without any meaningful data stored in it | |
| 79 const static uint32_t kEmptyAtlasRowKey = 0xffffffff; | |
| 80 | |
| 81 /** | |
| 82 * The state of a single row in our cache, next/prev pointers allow these to
be chained | |
| 83 * together to represent LRU status | |
| 84 */ | |
| 85 struct AtlasRow : SkNoncopyable { | |
| 86 AtlasRow() : fKey(kEmptyAtlasRowKey), fLocks(0), fNext(nullptr), fPrev(n
ullptr) { } | |
| 87 // GenerationID of the bitmap that is represented by this row, 0xfffffff
f means "empty" | |
| 88 uint32_t fKey; | |
| 89 // How many times this has been locked (0 == unlocked) | |
| 90 int32_t fLocks; | |
| 91 // We maintain an LRU linked list between unlocked nodes with these poin
ters | |
| 92 AtlasRow* fNext; | |
| 93 AtlasRow* fPrev; | |
| 94 }; | |
| 95 | |
| 96 /** | |
| 97 * We'll only allow construction via the static GrTextureStripAtlas::GetAtla
s | |
| 98 */ | |
| 99 GrTextureStripAtlas(Desc desc); | |
| 100 | |
| 101 void lockTexture(); | |
| 102 void unlockTexture(); | |
| 103 | |
| 104 /** | |
| 105 * Initialize our LRU list (if one already exists, clear it and start anew) | |
| 106 */ | |
| 107 void initLRU(); | |
| 108 | |
| 109 /** | |
| 110 * Grabs the least recently used free row out of the LRU list, returns nullp
tr if no rows are free. | |
| 111 */ | |
| 112 AtlasRow* getLRU(); | |
| 113 | |
| 114 void appendLRU(AtlasRow* row); | |
| 115 void removeFromLRU(AtlasRow* row); | |
| 116 | |
| 117 /** | |
| 118 * Searches the key table for a key and returns the index if found; if not f
ound, it returns | |
| 119 * the bitwise not of the index at which we could insert the key to maintain
a sorted list. | |
| 120 **/ | |
| 121 int searchByKey(uint32_t key); | |
| 122 | |
| 123 /** | |
| 124 * Compare two atlas rows by key, so we can sort/search by key | |
| 125 */ | |
| 126 static bool KeyLess(const AtlasRow& lhs, const AtlasRow& rhs) { | |
| 127 return lhs.fKey < rhs.fKey; | |
| 128 } | |
| 129 | |
| 130 #ifdef SK_DEBUG | |
| 131 void validate(); | |
| 132 #endif | |
| 133 | |
| 134 /** | |
| 135 * Clean up callback registered with GrContext. Allows this class to | |
| 136 * free up any allocated AtlasEntry and GrTextureStripAtlas objects | |
| 137 */ | |
| 138 static void CleanUp(const GrContext* context, void* info); | |
| 139 | |
| 140 // Hash table entry for atlases | |
| 141 class AtlasEntry : public ::SkNoncopyable { | |
| 142 public: | |
| 143 // for SkTDynamicHash | |
| 144 static const Desc& GetKey(const AtlasEntry& entry) { return entry.fDesc;
} | |
| 145 static uint32_t Hash(const Desc& desc) { return SkOpts::hash(&desc, size
of(Desc)); } | |
| 146 | |
| 147 // AtlasEntry proper | |
| 148 AtlasEntry() : fAtlas(nullptr) {} | |
| 149 ~AtlasEntry() { delete fAtlas; } | |
| 150 Desc fDesc; | |
| 151 GrTextureStripAtlas* fAtlas; | |
| 152 }; | |
| 153 | |
| 154 class Hash; | |
| 155 static Hash* gAtlasCache; | |
| 156 | |
| 157 static Hash* GetCache(); | |
| 158 | |
| 159 // We increment gCacheCount for each atlas | |
| 160 static int32_t gCacheCount; | |
| 161 | |
| 162 // A unique ID for this texture (formed with: gCacheCount++), so we can be s
ure that if we | |
| 163 // get a texture back from the texture cache, that it's the same one we last
used. | |
| 164 const int32_t fCacheKey; | |
| 165 | |
| 166 // Total locks on all rows (when this reaches zero, we can unlock our textur
e) | |
| 167 int32_t fLockedRows; | |
| 168 | |
| 169 const Desc fDesc; | |
| 170 const uint16_t fNumRows; | |
| 171 GrTexture* fTexture; | |
| 172 | |
| 173 SkScalar fNormalizedYHeight; | |
| 174 | |
| 175 // Array of AtlasRows which store the state of all our rows. Stored in a con
tiguous array, in | |
| 176 // order that they appear in our texture, this means we can subtract this po
inter from a row | |
| 177 // pointer to get its index in the texture, and can save storing a row numbe
r in AtlasRow. | |
| 178 AtlasRow* fRows; | |
| 179 | |
| 180 // Head and tail for linked list of least-recently-used rows (front = least
recently used). | |
| 181 // Note that when a texture is locked, it gets removed from this list until
it is unlocked. | |
| 182 AtlasRow* fLRUFront; | |
| 183 AtlasRow* fLRUBack; | |
| 184 | |
| 185 // A list of pointers to AtlasRows that currently contain cached images, sor
ted by key | |
| 186 SkTDArray<AtlasRow*> fKeyTable; | |
| 187 }; | |
| 188 | |
| 189 #endif | |
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Chromium Code Reviews
Issue 2262233002:
Make GrTextureStripAtlas flush pending IO on newly acquired texture (Closed)
Base URL: https://chromium.googlesource.com/skia.git@master