//Expand paletted or RGB images with transparency to full alpha channels so the data will be available as RGBA quartets.
if(png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
{
png_set_tRNS_to_alpha(png_ptr);
}

//png_read_update_info(png_ptr, info_ptr);
u8* rgba = new u8[width * height * 4]; //each pixel(RGBA) has 4 bytes
png_bytep * row_pointers;
row_pointers = (png_bytep*)png_malloc(sizeof(png_bytep) * height);
for (int y = 0; y < height; y++)
{
row_pointers[y] = (png_bytep)png_malloc(width<<2); //each pixel(RGBA) has 4 bytes
}
png_read_image(png_ptr, row_pointers);

//unlike store the pixel data from top-left corner, store them from bottom-left corner for OGLES Texture drawing...
int pos = (width * height * 4) - (4 * width);
for(int row = 0; row < height; row++)
{
for(int col = 0; col < (4 * width); col += 4)
{
rgba[pos++] = row_pointers[row][col]; // red
rgba[pos++] = row_pointers[row][col + 1]; // green
rgba[pos++] = row_pointers[row][col + 2]; // blue
rgba[pos++] = row_pointers[row][col + 3]; // alpha
}
pos=(pos - (width * 4)*2); //move the pointer back two rows
}

ImageInfo* imageInfo = (ImageInfo*)kdMalloc(sizeof(ImageInfo));
imageInfo->pixelData = rgba;
imageInfo->imageHeight = height;
imageInfo->imageWidth = width;

//clean up after the read, and free any memory allocated
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return imageInfo;
}

//----------------------------------------------------------------------------------------------------------------

ImageInfo* decodePNGFromFile(char* fileName)
{
char png_header[8];
png_structp png_ptr;
png_infop info_ptr;
int width, height, rowBytes;
png_byte color_type;
png_byte bit_depth;
png_colorp palette;

/* open file and test for it being a png */
FILE *file = fopen(fileName, "rb");
fread(png_header, 1, 8, file);
if(png_sig_cmp((png_bytep)png_header, 0, 8))
{
TFC_DEBUG("Not a PNG file...");
fclose(file);
}
/* initialise structures for reading a png file */
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
info_ptr = png_create_info_struct(png_ptr);
if (setjmp(png_jmpbuf(png_ptr)))
{
png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL);
TFC_DEBUG("ReadPngFile: Failed to read the PNG file");
fclose(file);
}
//I/O initialisation methods
png_init_io(png_ptr, file);
png_set_sig_bytes(png_ptr, 8); //Required!!!

/* **************************************************
* The high-level read interface in libpng (http://www.libpng.org/pub/png/libpng-1.2.5-manual.html)
* **************************************************
*/
png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_EXPAND, 0);
width = info_ptr->width;
height = info_ptr->height;
unsigned char* rgba = new unsigned char[width * height * 4]; //each pixel(RGBA) has 4 bytes
png_bytep* row_pointers = png_get_rows(png_ptr, info_ptr);