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718 lines
17 KiB
718 lines
17 KiB
/* |
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img_png.c - png format load & save |
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Copyright (C) 2019 Andrey Akhmichin |
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|
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This program is free software: you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation, either version 3 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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*/ |
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|
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#include "miniz.h" |
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#include "imagelib.h" |
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#include "xash3d_mathlib.h" |
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#include "img_png.h" |
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|
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#if defined(XASH_NO_NETWORK) |
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#include "platform/stub/net_stub.h" |
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#elif XASH_NSWITCH |
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// our ntohl is here |
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#include <arpa/inet.h> |
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#elif !XASH_WIN32 |
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#include <netinet/in.h> |
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#endif |
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static const char png_sign[] = {0x89, 'P', 'N', 'G', '\r', '\n', 0x1a, '\n'}; |
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static const char ihdr_sign[] = {'I', 'H', 'D', 'R'}; |
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static const char trns_sign[] = {'t', 'R', 'N', 'S'}; |
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static const char plte_sign[] = {'P', 'L', 'T', 'E'}; |
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static const char idat_sign[] = {'I', 'D', 'A', 'T'}; |
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static const char iend_sign[] = {'I', 'E', 'N', 'D'}; |
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static const int iend_crc32 = 0xAE426082; |
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|
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/* |
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============= |
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Image_LoadPNG |
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============= |
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*/ |
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qboolean Image_LoadPNG( const char *name, const byte *buffer, fs_offset_t filesize ) |
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{ |
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int ret; |
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short p, a, b, c, pa, pb, pc; |
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byte *buf_p, *pixbuf, *raw, *prior, *idat_buf = NULL, *uncompressed_buffer = NULL; |
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byte *pallete = NULL, *trns = NULL; |
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uint chunk_len, trns_len, plte_len, crc32, crc32_check, oldsize = 0, newsize = 0, rowsize; |
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uint uncompressed_size, pixel_size, pixel_count, i, y, filter_type, chunk_sign, r_alpha, g_alpha, b_alpha; |
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qboolean has_iend_chunk = false; |
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z_stream stream = {0}; |
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png_t png_hdr; |
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|
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if( filesize < sizeof( png_hdr ) ) |
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return false; |
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buf_p = (byte *)buffer; |
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|
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// get png header |
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memcpy( &png_hdr, buffer, sizeof( png_t ) ); |
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|
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// check png signature |
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if( memcmp( png_hdr.sign, png_sign, sizeof( png_sign ) ) ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Invalid PNG signature (%s)\n", name ); |
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return false; |
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} |
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// convert IHDR chunk length to little endian |
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png_hdr.ihdr_len = ntohl( png_hdr.ihdr_len ); |
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// check IHDR chunk length (valid value - 13) |
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if( png_hdr.ihdr_len != sizeof( png_ihdr_t ) ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Invalid IHDR chunk size %u (%s)\n", png_hdr.ihdr_len, name ); |
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return false; |
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} |
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// check IHDR chunk signature |
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if( memcmp( png_hdr.ihdr_sign, ihdr_sign, sizeof( ihdr_sign ) ) ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: IHDR chunk corrupted (%s)\n", name ); |
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return false; |
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} |
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// convert image width and height to little endian |
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image.height = png_hdr.ihdr_chunk.height = ntohl( png_hdr.ihdr_chunk.height ); |
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image.width = png_hdr.ihdr_chunk.width = ntohl( png_hdr.ihdr_chunk.width ); |
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if( png_hdr.ihdr_chunk.height == 0 || png_hdr.ihdr_chunk.width == 0 ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Invalid image size %ux%u (%s)\n", png_hdr.ihdr_chunk.width, png_hdr.ihdr_chunk.height, name ); |
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return false; |
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} |
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|
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if( !Image_ValidSize( name )) |
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return false; |
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if( png_hdr.ihdr_chunk.bitdepth != 8 ) |
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{ |
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Con_DPrintf( S_WARN "Image_LoadPNG: Only 8-bit images is supported (%s)\n", name ); |
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return false; |
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} |
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if( !( png_hdr.ihdr_chunk.colortype == PNG_CT_RGB |
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|| png_hdr.ihdr_chunk.colortype == PNG_CT_RGBA |
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|| png_hdr.ihdr_chunk.colortype == PNG_CT_GREY |
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|| png_hdr.ihdr_chunk.colortype == PNG_CT_ALPHA |
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|| png_hdr.ihdr_chunk.colortype == PNG_CT_PALLETE ) ) |
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{ |
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Con_DPrintf( S_WARN "Image_LoadPNG: Unknown color type %u (%s)\n", png_hdr.ihdr_chunk.colortype, name ); |
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return false; |
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} |
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if( png_hdr.ihdr_chunk.compression > 0 ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Unknown compression method %u (%s)\n", png_hdr.ihdr_chunk.compression, name ); |
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return false; |
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} |
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if( png_hdr.ihdr_chunk.filter > 0 ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Unknown filter type %u (%s)\n", png_hdr.ihdr_chunk.filter, name ); |
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return false; |
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} |
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if( png_hdr.ihdr_chunk.interlace == 1 ) |
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{ |
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Con_DPrintf( S_WARN "Image_LoadPNG: Adam7 Interlacing not supported (%s)\n", name ); |
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return false; |
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} |
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if( png_hdr.ihdr_chunk.interlace > 0 ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Unknown interlacing type %u (%s)\n", png_hdr.ihdr_chunk.interlace, name ); |
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return false; |
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} |
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// calculate IHDR chunk CRC |
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CRC32_Init( &crc32_check ); |
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CRC32_ProcessBuffer( &crc32_check, buf_p + sizeof( png_hdr.sign ) + sizeof( png_hdr.ihdr_len ), png_hdr.ihdr_len + sizeof( png_hdr.ihdr_sign ) ); |
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crc32_check = CRC32_Final( crc32_check ); |
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// check IHDR chunk CRC |
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if( ntohl( png_hdr.ihdr_crc32 ) != crc32_check ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: IHDR chunk has wrong CRC32 sum (%s)\n", name ); |
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return false; |
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} |
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// move pointer |
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buf_p += sizeof( png_hdr ); |
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|
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// find all critical chunks |
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while( !has_iend_chunk && ( buf_p - buffer ) < filesize ) |
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{ |
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// get chunk length |
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memcpy( &chunk_len, buf_p, sizeof( chunk_len ) ); |
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// convert chunk length to little endian |
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chunk_len = ntohl( chunk_len ); |
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if( chunk_len > INT_MAX ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Found chunk with wrong size (%s)\n", name ); |
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if( idat_buf ) Mem_Free( idat_buf ); |
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return false; |
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} |
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if( chunk_len > filesize - ( buf_p - buffer )) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Found chunk with size past file size (%s)\n", name ); |
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if( idat_buf ) Mem_Free( idat_buf ); |
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return false; |
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} |
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// move pointer |
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buf_p += sizeof( chunk_len ); |
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// find transparency |
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if( !memcmp( buf_p, trns_sign, sizeof( trns_sign ) ) ) |
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{ |
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trns = buf_p + sizeof( trns_sign ); |
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trns_len = chunk_len; |
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} |
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// find pallete for indexed image |
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else if( !memcmp( buf_p, plte_sign, sizeof( plte_sign ) ) ) |
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{ |
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pallete = buf_p + sizeof( plte_sign ); |
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plte_len = chunk_len / 3; |
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} |
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// get all IDAT chunks data |
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else if( !memcmp( buf_p, idat_sign, sizeof( idat_sign ) ) ) |
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{ |
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newsize = oldsize + chunk_len; |
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idat_buf = (byte *)Mem_Realloc( host.imagepool, idat_buf, newsize ); |
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memcpy( idat_buf + oldsize, buf_p + sizeof( idat_sign ), chunk_len ); |
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oldsize = newsize; |
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} |
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else if( !memcmp( buf_p, iend_sign, sizeof( iend_sign ) ) ) |
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has_iend_chunk = true; |
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// calculate chunk CRC |
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CRC32_Init( &crc32_check ); |
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CRC32_ProcessBuffer( &crc32_check, buf_p, chunk_len + sizeof( idat_sign ) ); |
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crc32_check = CRC32_Final( crc32_check ); |
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// move pointer |
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buf_p += sizeof( chunk_sign ); |
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buf_p += chunk_len; |
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// get real chunk CRC |
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memcpy( &crc32, buf_p, sizeof( crc32 ) ); |
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// check chunk CRC |
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if( ntohl( crc32 ) != crc32_check ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Found chunk with wrong CRC32 sum (%s)\n", name ); |
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if( idat_buf ) Mem_Free( idat_buf ); |
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return false; |
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} |
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// move pointer |
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buf_p += sizeof( crc32 ); |
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} |
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if( oldsize == 0 ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Couldn't find IDAT chunks (%s)\n", name ); |
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return false; |
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} |
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if( png_hdr.ihdr_chunk.colortype == PNG_CT_PALLETE && !pallete ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: PLTE chunk not found (%s)\n", name ); |
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Mem_Free( idat_buf ); |
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return false; |
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} |
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if( !has_iend_chunk ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: IEND chunk not found (%s)\n", name ); |
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Mem_Free( idat_buf ); |
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return false; |
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} |
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if( chunk_len != 0 ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: IEND chunk has wrong size %u (%s)\n", chunk_len, name ); |
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Mem_Free( idat_buf ); |
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return false; |
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} |
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switch( png_hdr.ihdr_chunk.colortype ) |
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{ |
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case PNG_CT_GREY: |
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case PNG_CT_PALLETE: |
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pixel_size = 1; |
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break; |
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case PNG_CT_ALPHA: |
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pixel_size = 2; |
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break; |
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case PNG_CT_RGB: |
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pixel_size = 3; |
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break; |
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case PNG_CT_RGBA: |
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pixel_size = 4; |
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break; |
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default: |
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pixel_size = 0; // make compiler happy |
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ASSERT( false ); |
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break; |
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} |
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image.type = PF_RGBA_32; // always exctracted to 32-bit buffer |
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pixel_count = image.height * image.width; |
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image.size = pixel_count * 4; |
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if( png_hdr.ihdr_chunk.colortype & PNG_CT_RGB ) |
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image.flags |= IMAGE_HAS_COLOR; |
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if( trns || ( png_hdr.ihdr_chunk.colortype & PNG_CT_ALPHA ) ) |
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image.flags |= IMAGE_HAS_ALPHA; |
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image.depth = 1; |
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rowsize = pixel_size * image.width; |
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uncompressed_size = image.height * ( rowsize + 1 ); // +1 for filter |
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uncompressed_buffer = Mem_Malloc( host.imagepool, uncompressed_size ); |
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stream.next_in = idat_buf; |
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stream.total_in = stream.avail_in = newsize; |
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stream.next_out = uncompressed_buffer; |
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stream.total_out = stream.avail_out = uncompressed_size; |
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// uncompress image |
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if( inflateInit2( &stream, MAX_WBITS ) != Z_OK ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: IDAT chunk decompression failed (%s)\n", name ); |
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Mem_Free( uncompressed_buffer ); |
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Mem_Free( idat_buf ); |
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return false; |
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} |
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ret = inflate( &stream, Z_NO_FLUSH ); |
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inflateEnd( &stream ); |
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Mem_Free( idat_buf ); |
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if( ret != Z_OK && ret != Z_STREAM_END ) |
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{ |
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Con_DPrintf( S_ERROR "Image_LoadPNG: IDAT chunk decompression failed (%s)\n", name ); |
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Mem_Free( uncompressed_buffer ); |
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return false; |
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} |
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prior = pixbuf = image.rgba = Mem_Malloc( host.imagepool, image.size ); |
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i = 0; |
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raw = uncompressed_buffer; |
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if( png_hdr.ihdr_chunk.colortype != PNG_CT_RGBA ) |
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prior = pixbuf = raw; |
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filter_type = *raw++; |
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// decode adaptive filter |
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switch( filter_type ) |
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{ |
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case PNG_F_NONE: |
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case PNG_F_UP: |
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for( ; i < rowsize; i++ ) |
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pixbuf[i] = raw[i]; |
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break; |
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case PNG_F_SUB: |
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case PNG_F_PAETH: |
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for( ; i < pixel_size; i++ ) |
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pixbuf[i] = raw[i]; |
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for( ; i < rowsize; i++ ) |
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pixbuf[i] = raw[i] + pixbuf[i - pixel_size]; |
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break; |
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case PNG_F_AVERAGE: |
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for( ; i < pixel_size; i++ ) |
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pixbuf[i] = raw[i]; |
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for( ; i < rowsize; i++ ) |
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pixbuf[i] = raw[i] + ( pixbuf[i - pixel_size] >> 1 ); |
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break; |
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default: |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Found unknown filter type (%s)\n", name ); |
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Mem_Free( uncompressed_buffer ); |
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Mem_Free( image.rgba ); |
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return false; |
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} |
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for( y = 1; y < image.height; y++ ) |
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{ |
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i = 0; |
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pixbuf += rowsize; |
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raw += rowsize; |
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filter_type = *raw++; |
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switch( filter_type ) |
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{ |
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case PNG_F_NONE: |
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for( ; i < rowsize; i++ ) |
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pixbuf[i] = raw[i]; |
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break; |
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case PNG_F_SUB: |
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for( ; i < pixel_size; i++ ) |
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pixbuf[i] = raw[i]; |
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for( ; i < rowsize; i++ ) |
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pixbuf[i] = raw[i] + pixbuf[i - pixel_size]; |
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break; |
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case PNG_F_UP: |
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for( ; i < rowsize; i++ ) |
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pixbuf[i] = raw[i] + prior[i]; |
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break; |
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case PNG_F_AVERAGE: |
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for( ; i < pixel_size; i++ ) |
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pixbuf[i] = raw[i] + ( prior[i] >> 1 ); |
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for( ; i < rowsize; i++ ) |
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pixbuf[i] = raw[i] + ( ( pixbuf[i - pixel_size] + prior[i] ) >> 1 ); |
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break; |
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case PNG_F_PAETH: |
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for( ; i < pixel_size; i++ ) |
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pixbuf[i] = raw[i] + prior[i]; |
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for( ; i < rowsize; i++ ) |
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{ |
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a = pixbuf[i - pixel_size]; |
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b = prior[i]; |
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c = prior[i - pixel_size]; |
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p = a + b - c; |
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pa = abs( p - a ); |
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pb = abs( p - b ); |
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pc = abs( p - c ); |
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pixbuf[i] = raw[i]; |
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if( pc < pa && pc < pb ) |
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pixbuf[i] += c; |
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else if( pb < pa ) |
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pixbuf[i] += b; |
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else |
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pixbuf[i] += a; |
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} |
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break; |
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default: |
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Con_DPrintf( S_ERROR "Image_LoadPNG: Found unknown filter type (%s)\n", name ); |
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Mem_Free( uncompressed_buffer ); |
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Mem_Free( image.rgba ); |
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return false; |
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} |
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prior = pixbuf; |
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} |
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pixbuf = image.rgba; |
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raw = uncompressed_buffer; |
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switch( png_hdr.ihdr_chunk.colortype ) |
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{ |
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case PNG_CT_RGB: |
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if( trns ) |
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{ |
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r_alpha = trns[0] << 8 | trns[1]; |
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g_alpha = trns[2] << 8 | trns[3]; |
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b_alpha = trns[4] << 8 | trns[5]; |
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} |
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for( y = 0; y < pixel_count; y++, raw += pixel_size ) |
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{ |
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*pixbuf++ = raw[0]; |
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*pixbuf++ = raw[1]; |
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*pixbuf++ = raw[2]; |
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|
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if( trns && r_alpha == raw[0] |
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&& g_alpha == raw[1] |
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&& b_alpha == raw[2] ) |
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*pixbuf++ = 0; |
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else |
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*pixbuf++ = 0xFF; |
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} |
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break; |
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case PNG_CT_GREY: |
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if( trns ) |
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r_alpha = trns[0] << 8 | trns[1]; |
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|
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for( y = 0; y < pixel_count; y++, raw += pixel_size ) |
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{ |
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*pixbuf++ = raw[0]; |
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*pixbuf++ = raw[0]; |
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*pixbuf++ = raw[0]; |
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|
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if( trns && r_alpha == raw[0] ) |
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*pixbuf++ = 0; |
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else |
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*pixbuf++ = 0xFF; |
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} |
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break; |
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case PNG_CT_ALPHA: |
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for( y = 0; y < pixel_count; y++, raw += pixel_size ) |
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{ |
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*pixbuf++ = raw[0]; |
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*pixbuf++ = raw[0]; |
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*pixbuf++ = raw[0]; |
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*pixbuf++ = raw[1]; |
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} |
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break; |
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case PNG_CT_PALLETE: |
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for( y = 0; y < pixel_count; y++, raw += pixel_size ) |
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{ |
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if( raw[0] < plte_len ) |
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{ |
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*pixbuf++ = pallete[3 * raw[0] + 0]; |
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*pixbuf++ = pallete[3 * raw[0] + 1]; |
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*pixbuf++ = pallete[3 * raw[0] + 2]; |
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|
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if( trns && raw[0] < trns_len ) |
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*pixbuf++ = trns[raw[0]]; |
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else |
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*pixbuf++ = 0xFF; |
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} |
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else |
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{ |
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*pixbuf++ = 0; |
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*pixbuf++ = 0; |
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*pixbuf++ = 0; |
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*pixbuf++ = 0xFF; |
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} |
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} |
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break; |
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default: |
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break; |
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} |
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|
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Mem_Free( uncompressed_buffer ); |
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|
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return true; |
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} |
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|
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/* |
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============= |
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Image_SavePNG |
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============= |
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*/ |
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qboolean Image_SavePNG( const char *name, rgbdata_t *pix ) |
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{ |
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int ret; |
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uint y, outsize, pixel_size, filtered_size, idat_len; |
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uint ihdr_len, crc32, rowsize, big_idat_len; |
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byte *in, *buffer, *out, *filtered_buffer, *rowend; |
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z_stream stream = {0}; |
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png_t png_hdr; |
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png_footer_t png_ftr; |
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|
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if( FS_FileExists( name, false ) && !Image_CheckFlag( IL_ALLOW_OVERWRITE )) |
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return false; // already existed |
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|
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// bogus parameter check |
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if( !pix->buffer ) |
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return false; |
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|
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// get image description |
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switch( pix->type ) |
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{ |
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case PF_BGR_24: |
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case PF_RGB_24: pixel_size = 3; break; |
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case PF_BGRA_32: |
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case PF_RGBA_32: pixel_size = 4; break; |
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default: |
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return false; |
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} |
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|
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rowsize = pix->width * pixel_size; |
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|
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// get filtered image size |
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filtered_size = ( rowsize + 1 ) * pix->height; |
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|
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out = filtered_buffer = Mem_Malloc( host.imagepool, filtered_size ); |
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|
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// apply adaptive filter to image |
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switch( pix->type ) |
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{ |
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case PF_RGB_24: |
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case PF_RGBA_32: |
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for( y = 0; y < pix->height; y++ ) |
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{ |
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in = pix->buffer + y * pix->width * pixel_size; |
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*out++ = PNG_F_NONE; |
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rowend = in + rowsize; |
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for( ; in < rowend; in += pixel_size ) |
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{ |
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*out++ = in[0]; |
|
*out++ = in[1]; |
|
*out++ = in[2]; |
|
if( pix->flags & IMAGE_HAS_ALPHA ) |
|
*out++ = in[3]; |
|
} |
|
} |
|
break; |
|
case PF_BGR_24: |
|
case PF_BGRA_32: |
|
for( y = 0; y < pix->height; y++ ) |
|
{ |
|
in = pix->buffer + y * pix->width * pixel_size; |
|
*out++ = PNG_F_NONE; |
|
rowend = in + rowsize; |
|
for( ; in < rowend; in += pixel_size ) |
|
{ |
|
*out++ = in[2]; |
|
*out++ = in[1]; |
|
*out++ = in[0]; |
|
if( pix->flags & IMAGE_HAS_ALPHA ) |
|
*out++ = in[3]; |
|
} |
|
} |
|
break; |
|
} |
|
|
|
|
|
|
|
// 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; |
|
}
|
|
|