Initial KTX encoder

The encoder comes with tests to check that the encoding/decoding
operations between ETC encoded bitmaps and ARGB bitmaps are sane.

R=bsalomon@google.com, robertphillips@google.com

Author: krajcevski@google.com

Review URL: https://codereview.chromium.org/312353003
diff --git a/tests/KtxTest.cpp b/tests/KtxTest.cpp
new file mode 100644
index 0000000..ee6a17d
--- /dev/null
+++ b/tests/KtxTest.cpp
@@ -0,0 +1,168 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBitmap.h"
+#include "SkData.h"
+#include "SkDecodingImageGenerator.h"
+#include "SkForceLinking.h"
+#include "SkImageDecoder.h"
+#include "SkOSFile.h"
+#include "SkRandom.h"
+#include "SkStream.h"
+#include "Test.h"
+
+__SK_FORCE_IMAGE_DECODER_LINKING;
+
+/**
+ * First, make sure that writing an 8-bit RGBA KTX file and then
+ * reading it produces the same bitmap.
+ */
+DEF_TEST(KtxReadWrite, reporter) {
+
+    // Random number generator with explicit seed for reproducibility
+    SkRandom rand(0x1005cbad);
+
+    SkBitmap bm8888;
+    bm8888.setConfig(SkBitmap::kARGB_8888_Config, 128, 128);
+
+    bool pixelsAllocated = bm8888.allocPixels();
+    REPORTER_ASSERT(reporter, pixelsAllocated);
+
+    uint8_t *pixels = reinterpret_cast<uint8_t*>(bm8888.getPixels());
+    REPORTER_ASSERT(reporter, NULL != pixels);
+
+    if (NULL == pixels) {
+        return;
+    }
+    
+    uint8_t *row = pixels;
+    for (int y = 0; y < bm8888.height(); ++y) {        
+        for (int x = 0; x < bm8888.width(); ++x) {
+            uint8_t a = rand.nextRangeU(0, 255);
+            uint8_t r = rand.nextRangeU(0, 255);
+            uint8_t g = rand.nextRangeU(0, 255);
+            uint8_t b = rand.nextRangeU(0, 255);
+
+            SkPMColor &pixel = *(reinterpret_cast<SkPMColor*>(row + x*sizeof(SkPMColor)));
+            pixel = SkPreMultiplyARGB(a, r, g, b);
+        }
+        row += bm8888.rowBytes();
+    }
+    REPORTER_ASSERT(reporter, !(bm8888.empty()));
+
+    SkAutoDataUnref encodedData(SkImageEncoder::EncodeData(bm8888, SkImageEncoder::kKTX_Type, 0));
+    REPORTER_ASSERT(reporter, NULL != encodedData);
+
+    SkAutoTUnref<SkMemoryStream> stream(SkNEW_ARGS(SkMemoryStream, (encodedData)));
+    REPORTER_ASSERT(reporter, NULL != stream);
+
+    SkBitmap decodedBitmap;
+    bool imageDecodeSuccess = SkImageDecoder::DecodeStream(stream, &decodedBitmap);
+    REPORTER_ASSERT(reporter, imageDecodeSuccess);
+
+    REPORTER_ASSERT(reporter, decodedBitmap.config() == bm8888.config());
+    REPORTER_ASSERT(reporter, decodedBitmap.alphaType() == bm8888.alphaType());
+    REPORTER_ASSERT(reporter, decodedBitmap.width() == bm8888.width());
+    REPORTER_ASSERT(reporter, decodedBitmap.height() == bm8888.height());
+    REPORTER_ASSERT(reporter, !(decodedBitmap.empty()));
+
+    uint8_t *decodedPixels = reinterpret_cast<uint8_t*>(decodedBitmap.getPixels());
+    REPORTER_ASSERT(reporter, NULL != decodedPixels);
+    REPORTER_ASSERT(reporter, decodedBitmap.getSize() == bm8888.getSize());
+
+    if (NULL == decodedPixels) {
+        return;
+    }
+
+    REPORTER_ASSERT(reporter, memcmp(decodedPixels, pixels, decodedBitmap.getSize()) == 0);
+}
+
+/**
+ * Next test is to see whether or not reading an unpremultiplied KTX file accurately
+ * creates a premultiplied buffer...
+ */
+DEF_TEST(KtxReadUnpremul, reporter) {
+
+    static const uint8_t kHalfWhiteKTX[] = {
+        0xAB, 0x4B, 0x54, 0x58, 0x20, 0x31, // First twelve bytes is magic
+        0x31, 0xBB, 0x0D, 0x0A, 0x1A, 0x0A, // KTX identifier string
+        0x01, 0x02, 0x03, 0x04, // Then magic endian specifier
+        0x01, 0x14, 0x00, 0x00, // uint32_t fGLType;
+        0x01, 0x00, 0x00, 0x00, // uint32_t fGLTypeSize;
+        0x08, 0x19, 0x00, 0x00, // uint32_t fGLFormat;
+        0x58, 0x80, 0x00, 0x00, // uint32_t fGLInternalFormat;
+        0x08, 0x19, 0x00, 0x00, // uint32_t fGLBaseInternalFormat;
+        0x02, 0x00, 0x00, 0x00, // uint32_t fPixelWidth;
+        0x02, 0x00, 0x00, 0x00, // uint32_t fPixelHeight;
+        0x00, 0x00, 0x00, 0x00, // uint32_t fPixelDepth;
+        0x00, 0x00, 0x00, 0x00, // uint32_t fNumberOfArrayElements;
+        0x01, 0x00, 0x00, 0x00, // uint32_t fNumberOfFaces;
+        0x01, 0x00, 0x00, 0x00, // uint32_t fNumberOfMipmapLevels;
+        0x00, 0x00, 0x00, 0x00, // uint32_t fBytesOfKeyValueData;
+        0x10, 0x00, 0x00, 0x00, // image size: 2x2 image of RGBA = 4 * 4 = 16 bytes
+        0xFF, 0xFF, 0xFF, 0x80, // Pixel 1
+        0xFF, 0xFF, 0xFF, 0x80, // Pixel 2
+        0xFF, 0xFF, 0xFF, 0x80, // Pixel 3
+        0xFF, 0xFF, 0xFF, 0x80};// Pixel 4
+
+    SkAutoTUnref<SkMemoryStream> stream(
+        SkNEW_ARGS(SkMemoryStream, (kHalfWhiteKTX, sizeof(kHalfWhiteKTX))));
+    REPORTER_ASSERT(reporter, NULL != stream);
+
+    SkBitmap decodedBitmap;
+    bool imageDecodeSuccess = SkImageDecoder::DecodeStream(stream, &decodedBitmap);
+    REPORTER_ASSERT(reporter, imageDecodeSuccess);
+
+    REPORTER_ASSERT(reporter, decodedBitmap.config() == SkBitmap::kARGB_8888_Config);
+    REPORTER_ASSERT(reporter, decodedBitmap.alphaType() == kPremul_SkAlphaType);
+    REPORTER_ASSERT(reporter, decodedBitmap.width() == 2);
+    REPORTER_ASSERT(reporter, decodedBitmap.height() == 2);
+    REPORTER_ASSERT(reporter, !(decodedBitmap.empty()));
+
+    uint8_t *decodedPixels = reinterpret_cast<uint8_t*>(decodedBitmap.getPixels());
+    REPORTER_ASSERT(reporter, NULL != decodedPixels);
+
+    uint8_t *row = decodedPixels;
+    for (int j = 0; j < decodedBitmap.height(); ++j) {
+        for (int i = 0; i < decodedBitmap.width(); ++i) {
+            SkPMColor pixel = *(reinterpret_cast<SkPMColor*>(row + i*sizeof(SkPMColor)));
+            REPORTER_ASSERT(reporter, SkPreMultiplyARGB(0x80, 0xFF, 0xFF, 0xFF) == pixel);
+        }
+        row += decodedBitmap.rowBytes();
+    }
+}
+
+/**
+ * Finally, make sure that if we get ETC1 data from a PKM file that we can then
+ * accurately write it out into a KTX file (i.e. transferring the ETC1 data from
+ * the PKM to the KTX should produce an identical KTX to the one we have on file)
+ */
+DEF_TEST(KtxReexportPKM, reporter) {
+    SkString resourcePath = skiatest::Test::GetResourcePath();
+    SkString filename = SkOSPath::SkPathJoin(resourcePath.c_str(), "mandrill_128.pkm");
+
+    // Load PKM file into a bitmap
+    SkBitmap etcBitmap;
+    SkAutoTUnref<SkData> fileData(SkData::NewFromFileName(filename.c_str()));
+    REPORTER_ASSERT(reporter, NULL != fileData);
+
+    bool installDiscardablePixelRefSuccess =
+        SkInstallDiscardablePixelRef(
+            SkDecodingImageGenerator::Create(
+                fileData, SkDecodingImageGenerator::Options()), &etcBitmap);
+    REPORTER_ASSERT(reporter, installDiscardablePixelRefSuccess);
+
+    // Write the bitmap out to a KTX file.
+    SkData *ktxDataPtr = SkImageEncoder::EncodeData(etcBitmap, SkImageEncoder::kKTX_Type, 0);
+    SkAutoDataUnref newKtxData(ktxDataPtr);
+    REPORTER_ASSERT(reporter, NULL != ktxDataPtr);
+
+    // See is this data is identical to data in existing ktx file.
+    SkString ktxFilename = SkOSPath::SkPathJoin(resourcePath.c_str(), "mandrill_128.ktx");
+    SkAutoDataUnref oldKtxData(SkData::NewFromFileName(ktxFilename.c_str()));
+    REPORTER_ASSERT(reporter, oldKtxData->equals(newKtxData));
+}