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C-/C++-Quelltext

    png_byte Header[8];

    FILE *myFile = fopen(filename.c_str(), "rb");
    if (myFile == 0)
    {
        return 0;
    }

    fread(Header, 1, 8, myFile);

    if (png_sig_cmp(Header, 0, 8))
    {
        fclose(myFile);
        return 0;
    }

    png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
    if (!png_ptr)
    {
        fclose(myFile);
        return 0;
    }

    png_infop info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr)
    {
        png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
        fclose(myFile);
        return 0;
    }

    png_infop end_info = png_create_info_struct(png_ptr);
    if (!end_info)
    {
        png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
        fclose(myFile);
        return 0;
    }

    if (setjmp(png_jmpbuf(png_ptr))) {
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
        fclose(myFile);
        return 0;
    }

C-/C++-Quelltext

    // init png reading
    png_init_io(png_ptr, myFile);

    // let libpng know you already read the first 8 bytes
    png_set_sig_bytes(png_ptr, 8);

    // read all the info up to the image data
    png_read_info(png_ptr, info_ptr);

    // variables to pass to get info
    int bit_depth, color_type;
    png_uint_32 temp_width, temp_height;

    // get info about png
    png_get_IHDR(png_ptr, info_ptr, &temp_width, &temp_height, &bit_depth, &color_type,
        NULL, NULL, NULL);

    // Update the png info struct.
    png_read_update_info(png_ptr, info_ptr);

    // Row size in bytes.
    int rowbytes = png_get_rowbytes(png_ptr, info_ptr);

    // glTexImage2d requires rows to be 4-byte aligned
    rowbytes += 3 - ((rowbytes - 1) % 4);

    // Allocate the image_data as a big block, to be given to opengl
    png_byte * image_data;
    image_data = (png_byte*)malloc(rowbytes * temp_height * sizeof(png_byte) + 15);
    if (image_data == NULL)
    {
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
        fclose(myFile);
        return 0;
    }

    // row_pointers is for pointing to image_data for reading the png with libpng
    png_bytep * row_pointers = (png_bytep*)malloc(temp_height * sizeof(png_bytep));
    if (row_pointers == NULL)
    {
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
        free(image_data);
        fclose(myFile);
        return 0;
    }

    // set the individual row_pointers to point at the correct offsets of image_data
    unsigned int i;
    for (i = 0; i < temp_height; i++)
    {
        row_pointers[temp_height - 1 - i] = image_data + i * rowbytes;
    }

    // read the png into image_data through row_pointers
    png_read_image(png_ptr, row_pointers);