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Add support for compressed alpha ktx files

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R=robertphillips@google.com

Author: krajcevski@google.com

Review URL: https://codereview.chromium.org/447283002
This commit is contained in:
krajcevski 2014-08-07 10:58:43 -07:00 committed by Commit bot
parent 8aed3c151f
commit 86bc1247d2
1 changed files with 60 additions and 4 deletions
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64
src/images/SkImageDecoder_ktx.cpp
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@ -91,12 +91,39 @@ bool SkKTXImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
}
}
// Set the config...
bm->setInfo(SkImageInfo::MakeN32(sampler.scaledWidth(), sampler.scaledHeight(), alphaType));
// Search through the compressed formats to see if the KTX file is holding
// compressed data
bool ktxIsCompressed = false;
SkTextureCompressor::Format ktxCompressedFormat;
for (int i = 0; i < SkTextureCompressor::kFormatCnt; ++i) {
SkTextureCompressor::Format fmt = static_cast<SkTextureCompressor::Format>(i);
if (ktxFile.isCompressedFormat(fmt)) {
ktxIsCompressed = true;
ktxCompressedFormat = fmt;
break;
}
}
// If the compressed format is a grayscale image, then setup the bitmap properly...
bool isCompressedAlpha = ktxIsCompressed &&
((SkTextureCompressor::kLATC_Format == ktxCompressedFormat) ||
(SkTextureCompressor::kR11_EAC_Format == ktxCompressedFormat));
// Set the image dimensions and underlying pixel type.
if (isCompressedAlpha) {
const int w = sampler.scaledWidth();
const int h = sampler.scaledHeight();
bm->setInfo(SkImageInfo::MakeA8(w, h));
} else {
const int w = sampler.scaledWidth();
const int h = sampler.scaledHeight();
bm->setInfo(SkImageInfo::MakeN32(w, h, alphaType));
}
if (SkImageDecoder::kDecodeBounds_Mode == mode) {
return true;
}
// If we've made it this far, then we know how to grok the data.
if (!this->allocPixelRef(bm, NULL)) {
return false;
@ -105,7 +132,36 @@ bool SkKTXImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
// Lock the pixels, since we're about to write to them...
SkAutoLockPixels alp(*bm);
if (ktxFile.isCompressedFormat(SkTextureCompressor::kETC1_Format)) {
if (isCompressedAlpha) {
if (!sampler.begin(bm, SkScaledBitmapSampler::kGray, *this)) {
return false;
}
// Alpha data is only a single byte per pixel.
int nPixels = width * height;
SkAutoMalloc outRGBData(nPixels);
uint8_t *outRGBDataPtr = reinterpret_cast<uint8_t *>(outRGBData.get());
// Decode the compressed format
const uint8_t *buf = reinterpret_cast<const uint8_t *>(ktxFile.pixelData());
if (!SkTextureCompressor::DecompressBufferFromFormat(
outRGBDataPtr, width, buf, width, height, ktxCompressedFormat)) {
return false;
}
// Set each of the pixels...
const int srcRowBytes = width;
const int dstHeight = sampler.scaledHeight();
const uint8_t *srcRow = reinterpret_cast<uint8_t *>(outRGBDataPtr);
srcRow += sampler.srcY0() * srcRowBytes;
for (int y = 0; y < dstHeight; ++y) {
sampler.next(srcRow);
srcRow += sampler.srcDY() * srcRowBytes;
}
return true;
} else if (ktxFile.isCompressedFormat(SkTextureCompressor::kETC1_Format)) {
if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, *this)) {
return false;
}