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/*
* DdsFormat.cpp, part of VCMI engine
*
* Authors: listed in file AUTHORS in main folder
*
* License: GNU General Public License v2.0 or later
* Full text of license available in license.txt file, in main folder
*
*/
#include "StdInc.h"
#include "DdsFormat.h"
#include <SDL_surface.h>
#include <squish.h>
#include "../../../lib/filesystem/CInputStream.h"
void DdsFormat::touchLRU(CacheEntry & e, const std::string & key)
{
lruList.erase(e.lruIt);
lruList.push_front(key);
e.lruIt = lruList.begin();
}
void DdsFormat::evictIfNeeded()
{
while (currentDDSMemory > DDS_CACHE_MEMORY_CAP && !lruList.empty())
{
const std::string &oldKey = lruList.back();
auto it = ddsCache.find(oldKey);
if (it != ddsCache.end())
{
currentDDSMemory -= it->second.data.memSize;
lruList.pop_back();
ddsCache.erase(it);
}
else
{
lruList.pop_back();
}
}
}
void DdsFormat::insertIntoCache(const std::string & key, const CachedDDS & cd)
{
auto it = ddsCache.find(key);
if (it != ddsCache.end())
{
currentDDSMemory -= it->second.data.memSize;
lruList.erase(it->second.lruIt);
ddsCache.erase(it);
}
lruList.push_front(key);
CacheEntry entry;
entry.data = cd;
entry.lruIt = lruList.begin();
ddsCache.emplace(key, entry);
currentDDSMemory += cd.memSize;
evictIfNeeded();
}
SDL_Surface * DdsFormat::load(CInputStream * stream, const std::string & cacheName, const Rect * rect)
{
const std::string key = cacheName;
std::shared_ptr<std::vector<uint8_t>> rgba;
uint32_t w = 0;
uint32_t h = 0;
// ---------- Check Cache First ----------
{
std::lock_guard lock(cacheMutex);
auto it = ddsCache.find(key);
if (it != ddsCache.end())
{
touchLRU(it->second, key);
w = it->second.data.w;
h = it->second.data.h;
rgba = it->second.data.rgba;
// Continue to rectangle extraction
}
}
// Only decode DDS if cache miss
if (!rgba)
{
uint32_t magic = 0;
stream->read(reinterpret_cast<ui8*>(&magic), 4);
if (magic != FOURCC('D','D','S',' '))
return nullptr;
DDSHeader hdr{};
stream->read(reinterpret_cast<ui8*>(&hdr), sizeof(hdr));
w = hdr.width;
h = hdr.height;
uint32_t fourcc = hdr.pixel_format.fourCC;
int squishFlags = 0;
if (fourcc == FOURCC('D','X','T','1'))
squishFlags = squish::kDxt1;
else if (fourcc == FOURCC('D','X','T','5'))
squishFlags = squish::kDxt5;
else
return nullptr;
int blockBytes = (fourcc == FOURCC('D','X','T','1')) ? 8 : 16;
int blocks = ((w + 3) / 4) * ((h + 3) / 4);
int compressedSize = blocks * blockBytes;
std::vector<uint8_t> comp(compressedSize);
stream->read(comp.data(), compressedSize);
rgba = std::make_shared<std::vector<uint8_t>>(w * h * 4);
squish::DecompressImage(rgba->data(), w, h, comp.data(), squishFlags);
// Insert decoded DDS into cache
{
std::lock_guard<std::mutex> lock(cacheMutex);
CachedDDS cd;
cd.w = w;
cd.h = h;
cd.rgba = rgba;
cd.memSize = w * h * 4;
insertIntoCache(key, cd);
}
}
// ---------- Rectangle extraction ----------
int rx = 0;
int ry = 0;
int rw = static_cast<int>(w);
int rh = static_cast<int>(h);
if (rect)
{
rx = std::max(0, rect->x);
ry = std::max(0, rect->y);
rw = std::min(rect->w, static_cast<int>(w) - rx);
rh = std::min(rect->h, static_cast<int>(h) - ry);
if (rw <= 0 || rh <= 0)
return nullptr;
}
SDL_Surface* surf = SDL_CreateRGBSurfaceWithFormat(0, rw, rh, 32, SDL_PIXELFORMAT_RGBA32);
uint8_t* dst = static_cast<uint8_t*>(surf->pixels);
for (int y = 0; y < rh; ++y)
{
const uint8_t* srcLine = rgba->data() + ((ry + y) * w + rx) * 4;
std::copy_n(srcLine, rw * 4, dst + y * surf->pitch);
}
return surf;
}
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