You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
573 lines
14 KiB
573 lines
14 KiB
![]()
5 years ago
|
/*
|
||
|
img_png.c - png format load & save
|
||
|
Copyright (C) 2019 Andrey Akhmichin
|
||
|
|
||
|
This program is free software: you can redistribute it and/or modify
|
||
|
it under the terms of the GNU General Public License as published by
|
||
|
the Free Software Foundation, either version 3 of the License, or
|
||
|
(at your option) any later version.
|
||
|
|
||
|
This program is distributed in the hope that it will be useful,
|
||
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
GNU General Public License for more details.
|
||
|
*/
|
||
|
|
||
|
#ifdef _WIN32
|
||
|
#include <winsock.h>
|
||
|
#else
|
||
|
#include <netinet/in.h>
|
||
|
#endif
|
||
|
#define MINIZ_HEADER_FILE_ONLY
|
||
|
#include "miniz.h"
|
||
|
#include "imagelib.h"
|
||
|
#include "mathlib.h"
|
||
|
|
||
|
static const char png_sign[] = {0x89, 'P', 'N', 'G', '\r', '\n', 0x1a, '\n'};
|
||
|
static const char ihdr_sign[] = {'I', 'H', 'D', 'R'};
|
||
|
static const char idat_sign[] = {'I', 'D', 'A', 'T'};
|
||
|
static const char iend_sign[] = {'I', 'E', 'N', 'D'};
|
||
|
static const int iend_crc32 = 0xAE426082;
|
||
|
|
||
|
/*
|
||
|
=============
|
||
|
Image_LoadPNG
|
||
|
=============
|
||
|
*/
|
||
|
qboolean Image_LoadPNG( const char *name, const byte *buffer, fs_offset_t filesize )
|
||
|
{
|
||
|
int ret;
|
||
|
short p, a, b, c, pa, pb, pc;
|
||
|
byte *buf_p, *pixbuf, *raw, *prior, *idat_buf = NULL, *uncompressed_buffer = NULL, *rowend;
|
||
|
uint chunk_len, crc32, crc32_check, oldsize = 0, newsize, rowsize;
|
||
|
uint uncompressed_size, pixel_size, i, y, filter_type, chunk_sign;
|
||
|
qboolean has_iend_chunk = false;
|
||
|
z_stream stream = {0};
|
||
|
png_t png_hdr;
|
||
|
|
||
|
if( filesize < sizeof( png_hdr ) )
|
||
|
return false;
|
||
|
|
||
|
buf_p = (byte *)buffer;
|
||
|
|
||
|
// get png header
|
||
|
memcpy( &png_hdr, buffer, sizeof( png_t ) );
|
||
|
|
||
|
// check png signature
|
||
|
if( memcmp( png_hdr.sign, png_sign, sizeof( png_sign ) ) )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Invalid PNG signature (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
// convert IHDR chunk length to little endian
|
||
|
png_hdr.ihdr_len = ntohl( png_hdr.ihdr_len );
|
||
|
|
||
|
// check IHDR chunk length (valid value - 13)
|
||
|
if( png_hdr.ihdr_len != sizeof( png_ihdr_t ) )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Invalid IHDR chunk size (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
// check IHDR chunk signature
|
||
|
if( memcmp( png_hdr.ihdr_sign, ihdr_sign, sizeof( ihdr_sign ) ) )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: IHDR chunk corrupted (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
// convert image width and height to little endian
|
||
|
png_hdr.ihdr_chunk.height = ntohl( png_hdr.ihdr_chunk.height );
|
||
|
png_hdr.ihdr_chunk.width = ntohl( png_hdr.ihdr_chunk.width );
|
||
|
|
||
|
if( png_hdr.ihdr_chunk.height == 0 || png_hdr.ihdr_chunk.width == 0 )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Invalid image size %dx%d (%s)\n", png_hdr.ihdr_chunk.width, png_hdr.ihdr_chunk.height, name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
if( png_hdr.ihdr_chunk.bitdepth != 8 )
|
||
|
{
|
||
|
Con_DPrintf( S_WARN "Image_LoadPNG: Only 8-bit images is supported (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
if( png_hdr.ihdr_chunk.colortype != PNG_CT_RGB && png_hdr.ihdr_chunk.colortype != PNG_CT_RGBA )
|
||
|
{
|
||
|
Con_DPrintf( S_WARN "Image_LoadPNG: Only 8-bit RGB and RGBA images is supported (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
if( png_hdr.ihdr_chunk.compression > 0 )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Unknown compression method (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
if( png_hdr.ihdr_chunk.filter > 0 )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Unknown filter type (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
if( png_hdr.ihdr_chunk.interlace == 1 )
|
||
|
{
|
||
|
Con_DPrintf( S_WARN "Image_LoadPNG: Adam7 Interlacing not supported (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
if( png_hdr.ihdr_chunk.interlace > 0 )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Unknown interlacing type (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
// calculate IHDR chunk CRC
|
||
|
CRC32_Init( &crc32_check );
|
||
|
CRC32_ProcessBuffer( &crc32_check, buf_p + sizeof( png_hdr.sign ) + sizeof( png_hdr.ihdr_len ), png_hdr.ihdr_len + sizeof( png_hdr.ihdr_sign ) );
|
||
|
crc32_check = CRC32_Final( crc32_check );
|
||
|
|
||
|
// check IHDR chunk CRC
|
||
|
if( ntohl( png_hdr.ihdr_crc32 ) != crc32_check )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: IHDR chunk has wrong CRC32 sum (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
// move pointer
|
||
|
buf_p += sizeof( png_hdr );
|
||
|
|
||
|
// find all critical chunks
|
||
|
while( !has_iend_chunk && ( buf_p - buffer ) < filesize )
|
||
|
{
|
||
|
// get chunk length
|
||
|
memcpy( &chunk_len, buf_p, sizeof( chunk_len ) );
|
||
|
|
||
|
// convert chunk length to little endian
|
||
|
chunk_len = ntohl( chunk_len );
|
||
|
|
||
|
if( chunk_len > INT_MAX )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Found chunk with wrong size (%s)\n", name );
|
||
|
Mem_Free( idat_buf );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
// move pointer
|
||
|
buf_p += sizeof( chunk_sign );
|
||
|
|
||
|
// get all IDAT chunks data
|
||
|
if( !memcmp( buf_p, idat_sign, sizeof( idat_sign ) ) )
|
||
|
{
|
||
|
newsize = oldsize + chunk_len;
|
||
|
idat_buf = (byte *)Mem_Realloc( host.imagepool, idat_buf, newsize );
|
||
|
memcpy( idat_buf + oldsize, buf_p + sizeof( idat_sign ), chunk_len );
|
||
|
oldsize = newsize;
|
||
|
}
|
||
|
else if( !memcmp( buf_p, iend_sign, sizeof( iend_sign ) ) )
|
||
|
has_iend_chunk = true;
|
||
|
|
||
|
// calculate chunk CRC
|
||
|
CRC32_Init( &crc32_check );
|
||
|
CRC32_ProcessBuffer( &crc32_check, buf_p, chunk_len + sizeof( idat_sign ) );
|
||
|
crc32_check = CRC32_Final( crc32_check );
|
||
|
|
||
|
// move pointer
|
||
|
buf_p += sizeof( chunk_sign );
|
||
|
buf_p += chunk_len;
|
||
|
|
||
|
// get real chunk CRC
|
||
|
memcpy( &crc32, buf_p, sizeof( crc32 ) );
|
||
|
|
||
|
// check chunk CRC
|
||
|
if( ntohl( crc32 ) != crc32_check )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Found chunk with wrong CRC32 sum (%s)\n", name );
|
||
|
Mem_Free( idat_buf );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
// move pointer
|
||
|
buf_p += sizeof( crc32 );
|
||
|
}
|
||
|
|
||
|
if( !has_iend_chunk )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: IEND chunk not found (%s)\n", name );
|
||
|
Mem_Free( idat_buf );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
if( chunk_len != 0 )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: IEND chunk has wrong size (%s)\n", name );
|
||
|
Mem_Free( idat_buf );
|
||
|
}
|
||
|
|
||
|
if( oldsize == 0 )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Couldn't find IDAT chunks (%s)\n", name );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
switch( png_hdr.ihdr_chunk.colortype )
|
||
|
{
|
||
|
case PNG_CT_RGB:
|
||
|
pixel_size = 3;
|
||
|
break;
|
||
|
case PNG_CT_RGBA:
|
||
|
pixel_size = 4;
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
image.type = PF_RGBA_32; // always exctracted to 32-bit buffer
|
||
|
image.width = png_hdr.ihdr_chunk.width;
|
||
|
image.height = png_hdr.ihdr_chunk.height;
|
||
|
image.size = image.height * image.width * 4;
|
||
|
image.flags |= IMAGE_HAS_ALPHA | IMAGE_HAS_COLOR;
|
||
|
image.depth = 1;
|
||
|
|
||
|
rowsize = pixel_size * image.width;
|
||
|
|
||
|
uncompressed_size = image.height * ( rowsize + 1 ); // +1 for filter
|
||
|
uncompressed_buffer = Mem_Malloc( host.imagepool, uncompressed_size );
|
||
|
|
||
|
stream.next_in = idat_buf;
|
||
|
stream.total_in = stream.avail_in = newsize;
|
||
|
stream.next_out = uncompressed_buffer;
|
||
|
stream.total_out = stream.avail_out = uncompressed_size;
|
||
|
|
||
|
// uncompress image
|
||
|
if( inflateInit2( &stream, MAX_WBITS ) != Z_OK )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: IDAT chunk decompression failed (%s)\n", name );
|
||
|
Mem_Free( uncompressed_buffer );
|
||
|
Mem_Free( idat_buf );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
ret = inflate( &stream, Z_NO_FLUSH );
|
||
|
inflateEnd( &stream );
|
||
|
|
||
|
Mem_Free( idat_buf );
|
||
|
|
||
|
if( ret != Z_OK && ret != Z_STREAM_END )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: IDAT chunk decompression failed (%s)\n", name );
|
||
|
Mem_Free( uncompressed_buffer );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
prior = pixbuf = image.rgba = Mem_Malloc( host.imagepool, image.size );
|
||
|
|
||
|
i = 0;
|
||
|
|
||
|
raw = uncompressed_buffer;
|
||
|
|
||
|
if( png_hdr.ihdr_chunk.colortype == PNG_CT_RGB )
|
||
|
prior = pixbuf = raw;
|
||
|
|
||
|
filter_type = *raw++;
|
||
|
|
||
|
// decode adaptive filter
|
||
|
switch( filter_type )
|
||
|
{
|
||
|
case PNG_F_NONE:
|
||
|
case PNG_F_UP:
|
||
|
for( ; i < rowsize; i++ )
|
||
|
pixbuf[i] = raw[i];
|
||
|
break;
|
||
|
case PNG_F_SUB:
|
||
|
case PNG_F_PAETH:
|
||
|
for( ; i < pixel_size; i++ )
|
||
|
pixbuf[i] = raw[i];
|
||
|
|
||
|
for( ; i < rowsize; i++ )
|
||
|
pixbuf[i] = raw[i] + pixbuf[i - pixel_size];
|
||
|
break;
|
||
|
case PNG_F_AVERAGE:
|
||
|
for( ; i < pixel_size; i++ )
|
||
|
pixbuf[i] = raw[i];
|
||
|
|
||
|
for( ; i < rowsize; i++ )
|
||
|
pixbuf[i] = raw[i] + ( pixbuf[i - pixel_size] >> 1 );
|
||
|
break;
|
||
|
default:
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Found unknown filter type (%s)\n", name );
|
||
|
Mem_Free( uncompressed_buffer );
|
||
|
Mem_Free( image.rgba );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
for( y = 1; y < image.height; y++ )
|
||
|
{
|
||
|
i = 0;
|
||
|
|
||
|
pixbuf += rowsize;
|
||
|
raw += rowsize;
|
||
|
|
||
|
filter_type = *raw++;
|
||
|
|
||
|
switch( filter_type )
|
||
|
{
|
||
|
case PNG_F_NONE:
|
||
|
for( ; i < rowsize; i++ )
|
||
|
pixbuf[i] = raw[i];
|
||
|
break;
|
||
|
case PNG_F_SUB:
|
||
|
for( ; i < pixel_size; i++ )
|
||
|
pixbuf[i] = raw[i];
|
||
|
|
||
|
for( ; i < rowsize; i++ )
|
||
|
pixbuf[i] = raw[i] + pixbuf[i - pixel_size];
|
||
|
break;
|
||
|
case PNG_F_UP:
|
||
|
for( ; i < rowsize; i++ )
|
||
|
pixbuf[i] = raw[i] + prior[i];
|
||
|
break;
|
||
|
case PNG_F_AVERAGE:
|
||
|
for( ; i < pixel_size; i++ )
|
||
|
pixbuf[i] = raw[i] + ( prior[i] >> 1 );
|
||
|
|
||
|
for( ; i < rowsize; i++ )
|
||
|
pixbuf[i] = raw[i] + ( ( pixbuf[i - pixel_size] + prior[i] ) >> 1 );
|
||
|
break;
|
||
|
case PNG_F_PAETH:
|
||
|
for( ; i < pixel_size; i++ )
|
||
|
pixbuf[i] = raw[i] + prior[i];
|
||
|
|
||
|
for( ; i < rowsize; i++ )
|
||
|
{
|
||
|
a = pixbuf[i - pixel_size];
|
||
|
b = prior[i];
|
||
|
c = prior[i - pixel_size];
|
||
|
p = a + b - c;
|
||
|
pa = abs( p - a );
|
||
|
pb = abs( p - b );
|
||
|
pc = abs( p - c );
|
||
|
|
||
|
pixbuf[i] = raw[i];
|
||
|
|
||
|
if( pc < pa && pc < pb )
|
||
|
pixbuf[i] += c;
|
||
|
else if( pb < pa )
|
||
|
pixbuf[i] += b;
|
||
|
else
|
||
|
pixbuf[i] += a;
|
||
|
}
|
||
|
break;
|
||
|
default:
|
||
|
Con_DPrintf( S_ERROR "Image_LoadPNG: Found unknown filter type (%s)\n", name );
|
||
|
Mem_Free( uncompressed_buffer );
|
||
|
Mem_Free( image.rgba );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
prior = pixbuf;
|
||
|
}
|
||
|
|
||
|
// convert RGB-to-RGBA
|
||
|
if( png_hdr.ihdr_chunk.colortype == PNG_CT_RGB )
|
||
|
{
|
||
|
pixbuf = image.rgba;
|
||
|
raw = uncompressed_buffer;
|
||
|
|
||
|
for( y = 0; y < image.height; y++ )
|
||
|
{
|
||
|
rowend = raw + rowsize;
|
||
|
for( ; raw < rowend; raw += pixel_size )
|
||
|
{
|
||
|
*pixbuf++ = raw[0];
|
||
|
*pixbuf++ = raw[1];
|
||
|
*pixbuf++ = raw[2];
|
||
|
*pixbuf++ = 0xFF;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
Mem_Free( uncompressed_buffer );
|
||
|
|
||
|
return true;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
=============
|
||
|
Image_SavePNG
|
||
|
=============
|
||
|
*/
|
||
|
qboolean Image_SavePNG( const char *name, rgbdata_t *pix )
|
||
|
{
|
||
|
int ret;
|
||
|
uint y, outsize, pixel_size, filtered_size, idat_len;
|
||
|
uint ihdr_len, crc32, rowsize, big_idat_len;
|
||
|
byte *in, *buffer, *out, *filtered_buffer, *rowend;
|
||
|
z_stream stream = {0};
|
||
|
png_t png_hdr;
|
||
|
png_footer_t png_ftr;
|
||
|
|
||
|
if( FS_FileExists( name, false ) && !Image_CheckFlag( IL_ALLOW_OVERWRITE ))
|
||
|
return false; // already existed
|
||
|
|
||
|
if( !pix->buffer )
|
||
|
return false;
|
||
|
|
||
|
switch( pix->type )
|
||
|
{
|
||
|
case PF_RGB_24:
|
||
|
pixel_size = 3;
|
||
|
break;
|
||
|
case PF_RGBA_32:
|
||
|
pixel_size = 4;
|
||
|
break;
|
||
|
default:
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
rowsize = pix->width * pixel_size;
|
||
|
|
||
|
// get filtered image size
|
||
|
filtered_size = ( rowsize + 1 ) * pix->height;
|
||
|
|
||
|
out = filtered_buffer = Mem_Malloc( host.imagepool, filtered_size );
|
||
|
in = pix->buffer;
|
||
|
|
||
|
// apply adaptive filter to image
|
||
|
for( y = 0; y < pix->height; y++ )
|
||
|
{
|
||
|
*out++ = PNG_F_NONE;
|
||
|
rowend = in + rowsize;
|
||
|
for( ; in < rowend; )
|
||
|
{
|
||
|
*out++ = *in++;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// get IHDR chunk length
|
||
|
ihdr_len = sizeof( png_ihdr_t );
|
||
|
|
||
|
// predict IDAT chunk length
|
||
|
idat_len = deflateBound( NULL, filtered_size );
|
||
|
|
||
|
// calculate PNG filesize
|
||
|
outsize = sizeof( png_t );
|
||
|
outsize += sizeof( idat_len );
|
||
|
outsize += sizeof( idat_sign );
|
||
|
outsize += idat_len;
|
||
|
outsize += sizeof( png_footer_t );
|
||
|
|
||
|
// write PNG header
|
||
|
memcpy( png_hdr.sign, png_sign, sizeof( png_sign ) );
|
||
|
|
||
|
// write IHDR chunk length
|
||
|
png_hdr.ihdr_len = htonl( ihdr_len );
|
||
|
|
||
|
// write IHDR chunk signature
|
||
|
memcpy( png_hdr.ihdr_sign, ihdr_sign, sizeof( ihdr_sign ) );
|
||
|
|
||
|
// write image width
|
||
|
png_hdr.ihdr_chunk.width = htonl( pix->width );
|
||
|
|
||
|
// write image height
|
||
|
png_hdr.ihdr_chunk.height = htonl( pix->height );
|
||
|
|
||
|
// write image bitdepth
|
||
|
png_hdr.ihdr_chunk.bitdepth = 8;
|
||
|
|
||
|
// write image colortype
|
||
|
png_hdr.ihdr_chunk.colortype = ( pix->flags & IMAGE_HAS_ALPHA ) ? PNG_CT_RGBA : PNG_CT_RGB; // 8 bits of alpha
|
||
|
|
||
|
// write image comression method
|
||
|
png_hdr.ihdr_chunk.compression = 0;
|
||
|
|
||
|
// write image filter type
|
||
|
png_hdr.ihdr_chunk.filter = 0;
|
||
|
|
||
|
// write image interlacing
|
||
|
png_hdr.ihdr_chunk.interlace = 0;
|
||
|
|
||
|
// get IHDR chunk CRC
|
||
|
CRC32_Init( &crc32 );
|
||
|
CRC32_ProcessBuffer( &crc32, &png_hdr.ihdr_sign, ihdr_len + sizeof( ihdr_sign ) );
|
||
|
crc32 = CRC32_Final( crc32 );
|
||
|
|
||
|
// write IHDR chunk CRC
|
||
|
png_hdr.ihdr_crc32 = htonl( crc32 );
|
||
|
|
||
|
out = buffer = (byte *)Mem_Malloc( host.imagepool, outsize );
|
||
|
|
||
|
stream.next_in = filtered_buffer;
|
||
|
stream.avail_in = filtered_size;
|
||
|
stream.next_out = buffer + sizeof( png_hdr ) + sizeof( idat_len ) + sizeof( idat_sign );
|
||
|
stream.avail_out = idat_len;
|
||
|
|
||
|
// compress image
|
||
|
if( deflateInit( &stream, Z_BEST_COMPRESSION ) != Z_OK )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_SavePNG: deflateInit failed (%s)\n", name );
|
||
|
Mem_Free( filtered_buffer );
|
||
|
Mem_Free( buffer );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
ret = deflate( &stream, Z_FINISH );
|
||
|
deflateEnd( &stream );
|
||
|
|
||
|
Mem_Free( filtered_buffer );
|
||
|
|
||
|
if( ret != Z_OK && ret != Z_STREAM_END )
|
||
|
{
|
||
|
Con_DPrintf( S_ERROR "Image_SavePNG: IDAT chunk compression failed (%s)\n", name );
|
||
|
Mem_Free( buffer );
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
// get final filesize
|
||
|
outsize -= idat_len;
|
||
|
idat_len = stream.total_out;
|
||
|
outsize += idat_len;
|
||
|
|
||
|
memcpy( out, &png_hdr, sizeof( png_t ) );
|
||
|
|
||
|
out += sizeof( png_t );
|
||
|
|
||
|
// convert IDAT chunk length to big endian
|
||
|
big_idat_len = htonl( idat_len );
|
||
|
|
||
|
// write IDAT chunk length
|
||
|
memcpy( out, &big_idat_len, sizeof( idat_len ) );
|
||
|
|
||
|
out += sizeof( idat_len );
|
||
|
|
||
|
// write IDAT chunk signature
|
||
|
memcpy( out, idat_sign, sizeof( idat_sign ) );
|
||
|
|
||
|
// calculate IDAT chunk CRC
|
||
|
CRC32_Init( &crc32 );
|
||
|
CRC32_ProcessBuffer( &crc32, out, idat_len + sizeof( idat_sign ) );
|
||
|
crc32 = CRC32_Final( crc32 );
|
||
|
|
||
|
out += sizeof( idat_sign );
|
||
|
out += idat_len;
|
||
|
|
||
|
// write IDAT chunk CRC
|
||
|
png_ftr.idat_crc32 = htonl( crc32 );
|
||
|
|
||
|
// write IEND chunk length
|
||
|
png_ftr.iend_len = 0;
|
||
|
|
||
|
// write IEND chunk signature
|
||
|
memcpy( png_ftr.iend_sign, iend_sign, sizeof( iend_sign ) );
|
||
|
|
||
|
// write IEND chunk CRC
|
||
|
png_ftr.iend_crc32 = htonl( iend_crc32 );
|
||
|
|
||
|
// write PNG footer to buffer
|
||
|
memcpy( out, &png_ftr, sizeof( png_ftr ) );
|
||
|
|
||
|
FS_WriteFile( name, buffer, outsize );
|
||
|
|
||
|
Mem_Free( buffer );
|
||
|
return true;
|
||
|
}
|