StreamReader* FileUtil_Win32_Impl::LoadFile(const char* pszFileName)
{
if (!pszFileName || strlen(pszFileName) <= 0) return NULL;
std::string strFullPath = m_strRootPath + pszFileName;
FILE* pFile = NULL;
fopen_s(&pFile, strFullPath.c_str(), "rb");
if (pFile == NULL)
{
LOGE("open file failed: %s", strFullPath.c_str());
return NULL;
}
fseek(pFile, 0, SEEK_END);
uint nFileSize = ftell(pFile);
fseek(pFile, 0, SEEK_SET);
char* pszBuffer = new char[nFileSize+1];
int nReadSize = fread(pszBuffer, 1, nFileSize, pFile);
fclose(pFile);
pszBuffer[nFileSize] = '\0';
StreamReader* pStreamReader = new StreamReader(pszBuffer, nFileSize, true);
if (!pStreamReader || !pStreamReader->IsOK())
{
LOGE("create stream reader failed with file size: %d", nFileSize);
SAFE_DELETE(pStreamReader);
SAFE_DELETE_ARRAY(pszBuffer);
return NULL;
}
return pStreamReader;
}
bool Image::CreateImage(const char* pszImageFile)
{
StreamReader* pTextureStream = IFileUtil::GetInstance().LoadFile(pszImageFile);
if (!pTextureStream || !pTextureStream->IsOK())
{
SAFE_RELEASE(pTextureStream);
return false;
}
png_structp pPngStruct = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!pPngStruct)
{
png_destroy_read_struct(&pPngStruct, NULL, NULL);
// logout
LOGE("load image file failed: %s", pszImageFile);
SAFE_DELETE(pTextureStream);
return false;
}
png_infop pPngInfo = png_create_info_struct(pPngStruct);
if (!pPngInfo)
{
png_destroy_read_struct(&pPngStruct, &pPngInfo, NULL);
// logout
LOGE("create png info failed: %s", pszImageFile);
SAFE_DELETE(pTextureStream);
return false;
}
setjmp(png_jmpbuf(pPngStruct));
// define our own callback function for I/O instead of reading from a file
png_set_read_fn(pPngStruct, pTextureStream, PngReaderCallback);
png_read_info(pPngStruct, pPngInfo);
m_nImageWidth = png_get_image_width(pPngStruct, pPngInfo);
m_nImageHeight = png_get_image_height(pPngStruct, pPngInfo);
// can be PNG_COLOR_TYPE_RGB, PNG_COLOR_TYPE_PALETTE, ...
png_byte nColorType = png_get_color_type(pPngStruct, pPngInfo);
m_nBPP = png_get_bit_depth(pPngStruct, pPngInfo);
// convert stuff to appropriate formats!
if(nColorType == PNG_COLOR_TYPE_PALETTE)
{
png_set_packing(pPngStruct);
// expand data to 24-bit RGB or 32-bit RGBA if alpha available
png_set_palette_to_rgb(pPngStruct);
}
// expand data to 24-bit RGB or 32-bit RGBA if alpha available
if (nColorType == PNG_COLOR_TYPE_GRAY && m_nBPP < 8) png_set_expand_gray_1_2_4_to_8(pPngStruct);
if (nColorType == PNG_COLOR_TYPE_GRAY_ALPHA) png_set_gray_to_rgb(pPngStruct);
if (m_nBPP == 16) png_set_strip_16(pPngStruct);
// expand paletted or RGB images with transparency to full alpha channels so the data will be available as RGBA quartets.
if(png_get_valid(pPngStruct, pPngInfo, PNG_INFO_tRNS)) png_set_tRNS_to_alpha(pPngStruct);
// read image data into pRowPointers
uchar** pRowPointers = new uchar*[m_nImageHeight];
for (int y = 0; y < m_nImageHeight; y++)
{
pRowPointers[y] = new uchar[m_nImageWidth * 4]; //each pixel(RGBA) has 4 bytes
}
png_read_image(pPngStruct, pRowPointers);
// free the stream object and png structure
png_destroy_read_struct(&pPngStruct, &pPngInfo, NULL);
SAFE_RELEASE(pTextureStream);
// store image data into our pRGBAData, each pixel(RGBA) has 4 bytes
m_pPixelData = new uchar[m_nImageWidth * m_nImageHeight * 4];
//unlike store the pixel data from top-left corner, store them from bottom-left corner for OGLES Texture drawing...
int nCurrPos = (m_nImageWidth * m_nImageHeight * 4) - (4 * m_nImageWidth);
for(int row = 0; row < m_nImageHeight; row++)
{
for(int col = 0; col < (4 * m_nImageWidth); col += 4)
{
m_pPixelData[nCurrPos++] = pRowPointers[row][col + 0]; // red
m_pPixelData[nCurrPos++] = pRowPointers[row][col + 1]; // green
m_pPixelData[nCurrPos++] = pRowPointers[row][col + 2]; // blue
m_pPixelData[nCurrPos++] = pRowPointers[row][col + 3]; // alpha
}
nCurrPos = (nCurrPos - (m_nImageWidth * 4) * 2); //move the pointer back two rows
}
// free pRowPointers
for (int y = 0; y < m_nImageHeight; y++)
{
SAFE_DELETE_ARRAY(pRowPointers[y]);
}
SAFE_DELETE_ARRAY(pRowPointers);
return true;
}
