diff options
| -rw-r--r-- | src/core/SkMipMap.cpp | 18 | ||||
| -rw-r--r-- | src/core/SkMipMap.h | 17 | ||||
| -rw-r--r-- | tests/MipMapTest.cpp | 40 |
3 files changed, 48 insertions, 27 deletions
diff --git a/src/core/SkMipMap.cpp b/src/core/SkMipMap.cpp index e6f4bad6d2..355c1edebb 100644 --- a/src/core/SkMipMap.cpp +++ b/src/core/SkMipMap.cpp @@ -370,9 +370,9 @@ SkMipMap* SkMipMap::Build(const SkPixmap& src, SkDiscardableFactoryProc fact) { return nullptr; } // whip through our loop to compute the exact size needed - size_t size = 0; + size_t size = 0; int countLevels = ComputeLevelCount(src.width(), src.height()); - for (int currentMipLevel = countLevels; currentMipLevel > 0; currentMipLevel--) { + for (int currentMipLevel = countLevels; currentMipLevel >= 0; currentMipLevel--) { SkISize mipSize = ComputeLevelSize(src.width(), src.height(), currentMipLevel); size += SkColorTypeMinRowBytes(ct, mipSize.fWidth) * mipSize.fHeight; } @@ -502,19 +502,19 @@ SkISize SkMipMap::ComputeLevelSize(int baseWidth, int baseHeight, int level) { } int maxLevelCount = ComputeLevelCount(baseWidth, baseHeight); - if (level > maxLevelCount || level < 0) { + if (level >= maxLevelCount || level < 0) { return SkISize::Make(0, 0); } - if (level == 0) { - return SkISize::Make(baseWidth, baseHeight); - } - // OpenGL's spec requires that each mipmap level have height/width equal to // max(1, floor(original_height / 2^i) // (or original_width) where i is the mipmap level. - int width = SkTMax(1, baseWidth >> level); - int height = SkTMax(1, baseHeight >> level); + // SkMipMap does not include the base mip level. + // For example, it contains levels 1-x instead of 0-x. + // This is because the image used to create SkMipMap is the base level. + // So subtract 1 from the mip level to get the index stored by SkMipMap. + int width = SkTMax(1, baseWidth >> (level + 1)); + int height = SkTMax(1, baseHeight >> (level + 1)); return SkISize::Make(width, height); } diff --git a/src/core/SkMipMap.h b/src/core/SkMipMap.h index a230a23392..7c798ef833 100644 --- a/src/core/SkMipMap.h +++ b/src/core/SkMipMap.h @@ -18,15 +18,26 @@ class SkDiscardableMemory; typedef SkDiscardableMemory* (*SkDiscardableFactoryProc)(size_t bytes); +/* + * SkMipMap will generate mipmap levels when given a base mipmap level image. + * + * Any function which deals with mipmap levels indices will start with index 0 + * being the first mipmap level which was generated. Said another way, it does + * not include the base level in its range. + */ class SkMipMap : public SkCachedData { public: static SkMipMap* Build(const SkPixmap& src, SkDiscardableFactoryProc); static SkMipMap* Build(const SkBitmap& src, SkDiscardableFactoryProc); // Determines how many levels a SkMipMap will have without creating that mipmap. + // This does not include the base mipmap level that the user provided when + // creating the SkMipMap. static int ComputeLevelCount(int baseWidth, int baseHeight); // Determines the size of a given mipmap level. + // |level| is an index into the generated mipmap levels. It does not include + // the base level. So index 0 represents mipmap level 1. static SkISize ComputeLevelSize(int baseWidth, int baseHeight, int level); struct Level { @@ -35,7 +46,13 @@ public: }; bool extractLevel(const SkSize& scale, Level*) const; + + // countLevels returns the number of mipmap levels generated (which does not + // include the base mipmap level). int countLevels() const; + + // |index| is an index into the generated mipmap levels. It does not include + // the base level. So index 0 represents mipmap level 1. bool getLevel(int index, Level*) const; protected: diff --git a/tests/MipMapTest.cpp b/tests/MipMapTest.cpp index e8d02b878d..596e995868 100644 --- a/tests/MipMapTest.cpp +++ b/tests/MipMapTest.cpp @@ -64,11 +64,15 @@ static void test_mipmap_generation(int width, int height, int expectedMipLevelCo const int mipLevelCount = mm->countLevels(); REPORTER_ASSERT(reporter, mipLevelCount == expectedMipLevelCount); + REPORTER_ASSERT(reporter, mipLevelCount == SkMipMap::ComputeLevelCount(width, height)); for (int i = 0; i < mipLevelCount; ++i) { SkMipMap::Level level; REPORTER_ASSERT(reporter, mm->getLevel(i, &level)); // Make sure the mipmaps contain valid data and that the sizes are correct REPORTER_ASSERT(reporter, level.fPixmap.addr()); + SkISize size = SkMipMap::ComputeLevelSize(width, height, i); + REPORTER_ASSERT(reporter, level.fPixmap.width() == size.width()); + REPORTER_ASSERT(reporter, level.fPixmap.height() == size.height()); // + 1 because SkMipMap does not include the base mipmap level. int twoToTheMipLevel = 1 << (i + 1); @@ -161,34 +165,34 @@ struct LevelSizeScenario { DEF_TEST(MipMap_ComputeLevelSize, reporter) { const LevelSizeScenario tests[] = { // Test mipmaps with negative sizes - {-100, 100, 1, SkISize::Make(0, 0)}, - {100, -100, 1, SkISize::Make(0, 0)}, - {-100, -100, 1, SkISize::Make(0, 0)}, + {-100, 100, 0, SkISize::Make(0, 0)}, + {100, -100, 0, SkISize::Make(0, 0)}, + {-100, -100, 0, SkISize::Make(0, 0)}, // Test mipmaps with 0, 1, 2 as dimensions // (SkMipMap::Build requires a min size of 1) // // 0 - {0, 100, 1, SkISize::Make(0, 0)}, - {100, 0, 1, SkISize::Make(0, 0)}, - {0, 0, 1, SkISize::Make(0, 0)}, + {0, 100, 0, SkISize::Make(0, 0)}, + {100, 0, 0, SkISize::Make(0, 0)}, + {0, 0, 0, SkISize::Make(0, 0)}, // 1 - {1, 100, 1, SkISize::Make(1, 50)}, - {100, 1, 1, SkISize::Make(50, 1)}, - {1, 1, 1, SkISize::Make(0, 0)}, + {1, 100, 0, SkISize::Make(1, 50)}, + {100, 1, 0, SkISize::Make(50, 1)}, + {1, 1, 0, SkISize::Make(0, 0)}, // 2 - {2, 100, 1, SkISize::Make(1, 50)}, - {100, 2, 2, SkISize::Make(25, 1)}, - {2, 2, 1, SkISize::Make(1, 1)}, + {2, 100, 0, SkISize::Make(1, 50)}, + {100, 2, 1, SkISize::Make(25, 1)}, + {2, 2, 0, SkISize::Make(1, 1)}, // Test a handful of cases - {63, 63, 3, SkISize::Make(7, 7)}, - {64, 64, 3, SkISize::Make(8, 8)}, - {127, 127, 3, SkISize::Make(15, 15)}, - {64, 129, 4, SkISize::Make(4, 8)}, - {255, 32, 7, SkISize::Make(1, 1)}, - {500, 1000, 2, SkISize::Make(125, 250)}, + {63, 63, 2, SkISize::Make(7, 7)}, + {64, 64, 2, SkISize::Make(8, 8)}, + {127, 127, 2, SkISize::Make(15, 15)}, + {64, 129, 3, SkISize::Make(4, 8)}, + {255, 32, 6, SkISize::Make(1, 1)}, + {500, 1000, 1, SkISize::Make(125, 250)}, }; for (auto& currentTest : tests) { |