Function LoadPng

Source/SysGL/Graphics/NativeTextureGL.cpp:160–261

Thanks 71M/Shazz p_texture is either an existing texture (in case it must be of the correct dimensions and format) else a new texture is created and returned.

	//	correct dimensions and format) else a new texture is created and returned.
	//*****************************************************************************
	CRefPtr<CNativeTexture>	LoadPng( const char * p_filename, ETextureFormat texture_format )
	{
		const size_t	SIGNATURE_SIZE = 8;
		u8	signature[ SIGNATURE_SIZE ];

		FILE * fh = fopen( p_filename,"rb" );
		if (fh == NULL)
		{
			return NULL;
		}

		if (fread( signature, sizeof(u8), SIGNATURE_SIZE, fh ) != SIGNATURE_SIZE)
		{
			fclose(fh);
			return NULL;
		}

		if (!png_check_sig( signature, SIGNATURE_SIZE ))
		{
			return NULL;
		}

		png_struct * p_png_struct = png_create_read_struct( PNG_LIBPNG_VER_STRING, NULL, NULL, NULL );
		if (p_png_struct == NULL)
		{
			return NULL;
		}

		png_info * p_png_info = png_create_info_struct( p_png_struct );
		if (p_png_info == NULL)
		{
			png_destroy_read_struct( &p_png_struct, NULL, NULL );
			return NULL;
		}

		if (setjmp( png_jmpbuf(p_png_struct) ) != 0)
		{
			png_destroy_read_struct( &p_png_struct, NULL, NULL );
			return NULL;
		}

		png_init_io( p_png_struct, fh );
		png_set_sig_bytes( p_png_struct, SIGNATURE_SIZE );
		png_read_png( p_png_struct, p_png_info, PNG_TRANSFORM_STRIP_16 | PNG_TRANSFORM_PACKING | PNG_TRANSFORM_EXPAND | PNG_TRANSFORM_BGR, NULL );

		png_uint_32 width  = png_get_image_width( p_png_struct, p_png_info );
		png_uint_32 height = png_get_image_height( p_png_struct, p_png_info );

		CRefPtr<CNativeTexture>	texture = CNativeTexture::Create( width, height, texture_format );

		DAEDALUS_ASSERT( texture->GetWidth() >= width, "Width is unexpectedly small" );
		DAEDALUS_ASSERT( texture->GetHeight() >= height, "Height is unexpectedly small" );
		DAEDALUS_ASSERT( texture_format == texture->GetFormat(), "Texture format doesn't match" );

		u8 * buffer = new u8[ texture->GetBytesRequired() ];
		if( !buffer )
		{
			texture = NULL;