From 47cf44dc60819842bd86816d989891490cf0e4a7 Mon Sep 17 00:00:00 2001
From: Ryan Huffman <ryanhuffman@gmail.com>
Date: Wed, 26 Apr 2017 17:11:19 -0700
Subject: [PATCH] Store offset to min mip kv in KtxStorage

---
 libraries/gpu/src/gpu/Texture.h       |  1 +
 libraries/gpu/src/gpu/Texture_ktx.cpp | 17 ++++++++---------
 libraries/ktx/src/ktx/KTX.cpp         |  2 +-
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/libraries/gpu/src/gpu/Texture.h b/libraries/gpu/src/gpu/Texture.h
index 825e9237f5..502ad33143 100755
--- a/libraries/gpu/src/gpu/Texture.h
+++ b/libraries/gpu/src/gpu/Texture.h
@@ -330,6 +330,7 @@ public:
 
         std::string _filename;
         std::atomic<uint8_t> _minMipLevelAvailable;
+        size_t _offsetToMinMipKV;
 
         ktx::KTXDescriptorPointer _ktxDescriptor;
         friend class Texture;
diff --git a/libraries/gpu/src/gpu/Texture_ktx.cpp b/libraries/gpu/src/gpu/Texture_ktx.cpp
index e3c4b325fb..8181bb21ae 100644
--- a/libraries/gpu/src/gpu/Texture_ktx.cpp
+++ b/libraries/gpu/src/gpu/Texture_ktx.cpp
@@ -109,18 +109,18 @@ KtxStorage::KtxStorage(const std::string& filename) : _filename(filename) {
         if (_ktxDescriptor->images.size() < _ktxDescriptor->header.numberOfMipmapLevels) {
             qWarning() << "Bad images found in ktx";
         }
-        auto& keyValues = _ktxDescriptor->keyValues;
-        auto found = std::find_if(keyValues.begin(), keyValues.end(), [](const ktx::KeyValue& val) -> bool {
-            return val._key.compare(ktx::HIFI_MIN_POPULATED_MIP_KEY) == 0;
-        });
-        if (found != keyValues.end()) {
-            _minMipLevelAvailable = found->_value[0];
+
+        _offsetToMinMipKV = _ktxDescriptor->getValueOffsetForKey(ktx::HIFI_MIN_POPULATED_MIP_KEY);
+        if (_offsetToMinMipKV) {
+            auto data = storage->data() + ktx::KTX_HEADER_SIZE + _offsetToMinMipKV;
+            _minMipLevelAvailable = *data;
         } else {
             // Assume all mip levels are available
             _minMipLevelAvailable = 0;
         }
     }
 
+
     // now that we know the ktx, let's get the header info to configure this Texture::Storage:
     Format mipFormat = Format::COLOR_BGRA_32;
     Format texelFormat = Format::COLOR_SRGBA_32;
@@ -195,7 +195,6 @@ void KtxStorage::assignMipData(uint16 level, const storage::StoragePointer& stor
     imageData += ktx::KTX_HEADER_SIZE + _ktxDescriptor->header.bytesOfKeyValueData + _ktxDescriptor->images[level]._imageOffset;
     imageData += ktx::IMAGE_SIZE_WIDTH;
 
-    auto offset = _ktxDescriptor->getValueOffsetForKey(ktx::HIFI_MIN_POPULATED_MIP_KEY);
     {
         std::lock_guard<std::mutex> lock { _cacheFileWriteMutex };
 
@@ -206,8 +205,8 @@ void KtxStorage::assignMipData(uint16 level, const storage::StoragePointer& stor
 
         memcpy(imageData, storage->data(), _ktxDescriptor->images[level]._imageSize);
         _minMipLevelAvailable = level;
-        if (offset > 0) {
-            auto minMipKeyData = file->mutableData() + ktx::KTX_HEADER_SIZE + ktx::KV_SIZE_WIDTH + offset;
+        if (_offsetToMinMipKV > 0) {
+            auto minMipKeyData = file->mutableData() + ktx::KTX_HEADER_SIZE + _offsetToMinMipKV;
             memcpy(minMipKeyData, (void*)&_minMipLevelAvailable, 1);
         }
     }
diff --git a/libraries/ktx/src/ktx/KTX.cpp b/libraries/ktx/src/ktx/KTX.cpp
index 0dbc2e720f..cea397927a 100644
--- a/libraries/ktx/src/ktx/KTX.cpp
+++ b/libraries/ktx/src/ktx/KTX.cpp
@@ -126,7 +126,7 @@ size_t KTXDescriptor::getValueOffsetForKey(const std::string& key) const {
     size_t offset { 0 };
     for (auto& kv : keyValues) {
         if (kv._key == key) {
-            return offset + kv._key.size() + 1;
+            return offset + ktx::KV_SIZE_WIDTH + kv._key.size() + 1;
         }
         offset += kv.serializedByteSize();
     }