[原创]cocos2dx加载网络图片&异步加载图片

bool PNGCodec::PrepareDecode() {
  png_reader_.png_struct_ptr_= png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
  if (!png_reader_.png_struct_ptr_)
    return false;
  
  png_reader_.png_info_ptr_ = png_create_info_struct(png_reader_.png_struct_ptr_);
  if (!png_reader_.png_info_ptr_) {
    png_destroy_read_struct(&png_reader_.png_struct_ptr_, NULL, NULL);
    return false;
  }

  if (setjmp(png_jmpbuf(png_reader_.png_struct_ptr_))) {
    png_destroy_read_struct(&png_reader_.png_struct_ptr_, &png_reader_.png_info_ptr_, (png_infopp)NULL);
    return false;
  }
  
  png_set_error_fn(png_reader_.png_struct_ptr_, NULL, LogLibPNGDecodeError, LogLibPNGDecodeWarning);
  
  png_set_progressive_read_fn(png_reader_.png_struct_ptr_, &png_reader_, &DecodeInfoCallback,
                              &DecodeRowCallback, &DecodeEndCallback);
  png_reader_.decode_state_ = PNGCodec::DecodeState::DECODE_READY;
  return true;
}

/*
@parm1：png_structp
@parm2：自定义指针
@parm3：void *png_progressive_info_ptr(png_struct* png_ptr, png_info* info_ptr)
@parm4：void *png_progressive_row_ptr(png_struct* png_ptr, png_byte* new_row, png_uint_32 row_num, int pass)
@parm5：void png_progressive_end_ptr(png_struct* png_ptr, png_info* info)
*/
void, png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
    png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn))

#include "CCWebSprite.h"
#include "CCInterlacedPngImage.h"
#include "http_connection.h"
#include "png_codec.h"

#include <future>

namespace cocos2d {


      // Callback function used by libcurl for collect response data
size_t WebSprite::DataBridge::WriteData(void *ptr, size_t size, size_t nmemb, void *stream) {
  if (stream == nullptr) {
        return 0;
  }
  WebSprite* web_sprite = static_cast<WebSprite*>(stream);
    if (web_sprite == nullptr) {
        return 0;
    }
  size_t sizes = size * nmemb;
  web_sprite->reciverData((unsigned  char*)ptr, sizes);
  return sizes;
}

void WebSprite::DataBridge::ReadHeaderCompleteCallBack(void* ptr) {
    WebSprite* web_sprite = static_cast<WebSprite*>(ptr);
    web_sprite->readHeaderComplete();
}

void WebSprite::DataBridge::ReadRowCompleteCallBack(void* ptr, int pass) {
  WebSprite* web_sprite = static_cast<WebSprite*>(ptr);
  web_sprite->readRowComplete(pass);
}

void WebSprite::DataBridge::ReadAllCompleteCallBack(void* ptr) {
  WebSprite* web_sprite = static_cast<WebSprite*>(ptr);
  web_sprite->readAllComplete();
}


WebSprite::WebSprite() : http_connection_(nullptr),
    png_coder_(std::make_shared<util::PNGCodec>()), interlaced_png_image_buff_(new InterlacedPngImage()), code_pass_(-1){

}

WebSprite::~WebSprite() {
    if (http_connection_ != nullptr) {
        http_connection_->SetWriteCallBack(nullptr, WebSprite::DataBridge::WriteData);
    }
    png_coder_->SetReadCallBack(nullptr, nullptr, nullptr, nullptr);
    CC_SAFE_RELEASE(interlaced_png_image_buff_);
}

WebSprite* WebSprite::create() {
  WebSprite *sprite = new WebSprite();
  if (sprite && sprite->init())
  {
    sprite->autorelease();
    return sprite;
  }
  CC_SAFE_DELETE(sprite);
  return nullptr;
}

WebSprite* WebSprite::createWithFileUrl(const char *file_url) {
  WebSprite *sprite = new WebSprite();
  if (sprite && sprite->initWithFileUrl(file_url))
  {
    sprite->autorelease();
    return sprite;
  }
  CC_SAFE_DELETE(sprite);
  return nullptr;
}

bool WebSprite::initWithFileUrl(const char *file_url) {
  Sprite::init();
  file_url_ = file_url;
    if (isRemotoeFileUrl(file_url)) {
        return initWithRemoteFile();
    } else {
        return initWithLocalFile();
    }
}

bool WebSprite::initWithRemoteFile() {
    assert(http_connection_ == nullptr);
    http_connection_ = std::make_shared<HttpConnection>();
    http_connection_->Init(file_url_.c_str());
    png_coder_->PrepareDecode();
    png_coder_->SetReadCallBack(this, WebSprite::DataBridge::ReadHeaderCompleteCallBack, WebSprite::DataBridge::ReadRowCompleteCallBack, WebSprite::DataBridge::ReadAllCompleteCallBack);
    http_connection_->SetWriteCallBack(this, WebSprite::DataBridge::WriteData);
    this->scheduleUpdate();
    std::thread http_thread = std::thread(std::bind(&HttpConnection::PerformGet, http_connection_));
    http_thread.detach();
    return true;
}

bool WebSprite::initWithLocalFile() {
    auto filePath = FileUtils::getInstance()->fullPathForFilename(file_url_);
    std::shared_ptr<Data> data = std::make_shared<Data>(FileUtils::getInstance()->getDataFromFile(filePath));
    png_coder_->PrepareDecode();
    png_coder_->SetReadCallBack(this, &WebSprite::DataBridge::ReadHeaderCompleteCallBack, WebSprite::DataBridge::ReadRowCompleteCallBack, WebSprite::DataBridge::ReadAllCompleteCallBack);
    std::thread http_thread = std::thread(std::bind([=](){
                png_coder_->Decoding(data->getBytes(), data->getSize());
            }
        ));
    http_thread.detach();
    this->scheduleUpdate();
    return true;
}

bool WebSprite::isRemotoeFileUrl(const char *file_url) {
    if (strlen(file_url) > 7 && (strncmp(file_url, "http://", 7) == 0)) {
        return true;
    }
    return false;
}

void WebSprite::reciverData(unsigned char* data, size_t data_size) {
    png_coder_->Decoding(data, data_size);
}

void WebSprite::updateTexture() {
  cocos2d::Texture2D* texture = cocos2d::Director::getInstance()->getTextureCache()->addImage(interlaced_png_image_buff_, file_url_);
    texture->updateWithData(interlaced_png_image_buff_->getData(), 0, 0, interlaced_png_image_buff_->getWidth(),
                interlaced_png_image_buff_->getHeight());
    SpriteFrame* sprite_frame = cocos2d::SpriteFrame::createWithTexture(texture,
            CCRectMake(0,0,texture->getContentSize().width, texture->getContentSize().height));
    Sprite::setSpriteFrame(sprite_frame);
}

void WebSprite::readHeaderComplete() {
    interlaced_png_image_buff_->setImageHeader(png_coder_->png_width(), png_coder_->png_height(), png_coder_->png_color_type(), png_coder_->png_output_channels());
}

void WebSprite::readRowComplete(int pass) {
  if (code_pass_ < pass) {
    perform_mutex_.lock();
        interlaced_png_image_buff_->setImageBodyData((char*)png_coder_->png_data_buffer(), png_coder_->png_data_size());
    perform_main_thread_functions_.push_back(std::bind(&WebSprite::updateTexture, this));
    perform_mutex_.unlock();
    code_pass_ = pass;
  }
}

// run on sub thread
void WebSprite::readAllComplete() {
  perform_mutex_.lock();
    interlaced_png_image_buff_->setImageBodyData((char*)png_coder_->png_data_buffer(), png_coder_->png_data_size());
  perform_main_thread_functions_.push_back(std::bind(&WebSprite::updateTexture, this));
  perform_mutex_.unlock();
}

void WebSprite::update(float fDelta) {
  Sprite::update(fDelta);
  perform_mutex_.lock();
  for (std::vector<std::function<void ()> >::iterator it = perform_main_thread_functions_.begin();
       it != perform_main_thread_functions_.end(); ++it) {
    (*it)();
  } 
  perform_main_thread_functions_.clear();
  perform_mutex_.unlock();
}