OOPNGTextureLoader(OOPrivate) Category Reference

Instance Methods
(void)	- doLoadTexture
(void)	- readBytes:count:

Detailed Description

Definition at line 42 of file OOPNGTextureLoader.m.

Method Documentation

doLoadTexture

- (void) doLoadTexture

Extends class OOPNGTextureLoader.

Definition at line 240 of file OOPNGTextureLoader.m.

{
    png_bytepp                  rows = NULL;
    png_uint_32                 pngWidth,
                                pngHeight;
    int                         depth,
                                colorType;
    uint32_t                    i;
    
    // Set up PNG decoding
    png = png_create_read_struct(PNG_LIBPNG_VER_STRING, self, PNGError, PNGWarning);
    if (png != NULL)  pngInfo = png_create_info_struct(png);
    if (pngInfo != NULL)  pngEndInfo = png_create_info_struct(png);
    if (pngEndInfo == NULL)
    {
        OOLog(@"texture.load.png.setup.failed", @"***** Error preparing to read %@.", _path);
        goto FAIL;
    }
    
    if (EXPECT_NOT(setjmp(png_jmpbuf(png))))
    {
        // libpng will jump here on error.
        if (_data)
        {
            free(_data);
            _data = NULL;
        }
        goto FAIL;
    }
    
    png_set_read_fn(png, self, PNGRead);
    
    png_read_info(png, pngInfo);
    // Read header, get format info and check that it meets our expectations.
    if (EXPECT_NOT(!png_get_IHDR(png, pngInfo, &pngWidth, &pngHeight, &depth, &colorType, NULL, NULL, NULL)))
    {
        OOLog(@"texture.load.png.failed", @"Failed to get metadata from PNG %@", _path);
        goto FAIL;
    }
    png_set_strip_16(png);          // 16 bits per channel -> 8 bpc
    if (depth < 8 || colorType == PNG_COLOR_TYPE_PALETTE)
    {
        png_set_expand(png);        // Paletted -> RGB, greyscale -> 8 bpc
    }
    
    if (colorType == PNG_COLOR_TYPE_GRAY)
    {
        _format = kOOTextureDataGrayscale;
    }
    else if (colorType == PNG_COLOR_TYPE_GRAY_ALPHA)
    {
        _format = kOOTextureDataGrayscaleAlpha;
    }
    else
    {
        _format = kOOTextureDataRGBA;
        
#if OOLITE_BIG_ENDIAN
        png_set_bgr(png);
        png_set_swap_alpha(png);        // RGBA->ARGB
        png_set_filler(png, 0xFF, PNG_FILLER_BEFORE);
#elif OOLITE_LITTLE_ENDIAN
        png_set_filler(png, 0xFF, PNG_FILLER_AFTER);
#else
#error Unknown handle byte order.
#endif
    }
    
    png_read_update_info(png, pngInfo);
    png_set_interlace_handling(png);
    
    // Metadata is acceptable; load data.
    _width = pngWidth;
    _height = pngHeight;
    _rowBytes = png_get_rowbytes(png, pngInfo);
    
    // png_read_png
    rows = malloc(sizeof *rows * _height);
    _data = malloc(_rowBytes * _height);
    if (EXPECT_NOT(rows == NULL || _data == NULL))
    {
        if (rows != NULL)
        {
            free(rows);
            rows = NULL;
        }
        if (_data != NULL)
        {
            free(_data);
            _data = NULL;
        }
        OOLog(kOOLogAllocationFailure, @"Failed to allocate space (%zu bytes) for texture %@", _rowBytes * _height, _path);
        goto FAIL;
    }
    
    for (i = 0; i != _height; ++i)
    {
        rows[i] = ((png_bytep)_data) + i * _rowBytes;
    }
    png_read_image(png, rows);
    png_read_end(png, pngEndInfo);
    
FAIL:
    free(rows);
    png_destroy_read_struct(&png, &pngInfo, &pngEndInfo);
}

readBytes:count:

- (void) readBytes:		(png_bytep)	bytes
count:		(png_size_t)	count

Extends class OOPNGTextureLoader.

Definition at line 240 of file OOPNGTextureLoader.m.

                 :(png_bytep)bytes count:(png_size_t)count
{
    // Check that we're within the file's bounds
    if (EXPECT_NOT(length - offset < count))
    {
        NSString *message = [NSString stringWithFormat:@"attempt to read beyond end of file (%@), file may be truncated.", _path];
        png_error(png, [message UTF8String]);   // Will not return
    }
    
    assert(bytes != NULL);
    
    // Copy bytes
    memcpy(bytes, [fileData bytes] + offset, count);
    offset += count;
}

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The documentation for this category was generated from the following file:

• src/Core/Materials/OOPNGTextureLoader.m