mirror of https://github.com/minetest/minetest.git
69 lines
2.1 KiB
C++
Executable File
69 lines
2.1 KiB
C++
Executable File
/*
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Minetest
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Copyright (C) 2021 hecks
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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 Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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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 Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "png.h"
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#include <string>
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#include <sstream>
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#include <zlib.h>
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#include <cassert>
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#include "util/serialize.h"
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#include "serialization.h"
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#include "irrlichttypes.h"
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static void writeChunk(std::ostringstream &target, const std::string &chunk_str)
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{
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assert(chunk_str.size() >= 4);
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assert(chunk_str.size() - 4 < U32_MAX);
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writeU32(target, chunk_str.size() - 4); // Write length minus the identifier
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target << chunk_str;
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writeU32(target, crc32(0,(const u8*)chunk_str.data(), chunk_str.size()));
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}
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std::string encodePNG(const u8 *data, u32 width, u32 height, s32 compression)
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{
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auto file = std::ostringstream(std::ios::binary);
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file << "\x89PNG\r\n\x1a\n";
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{
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auto IHDR = std::ostringstream(std::ios::binary);
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IHDR << "IHDR";
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writeU32(IHDR, width);
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writeU32(IHDR, height);
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// 8 bpp, color type 6 (RGBA)
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IHDR.write("\x08\x06\x00\x00\x00", 5);
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writeChunk(file, IHDR.str());
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}
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{
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auto IDAT = std::ostringstream(std::ios::binary);
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IDAT << "IDAT";
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auto scanlines = std::ostringstream(std::ios::binary);
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for(u32 i = 0; i < height; i++) {
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scanlines.write("\x00", 1); // Null predictor
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scanlines.write((const char*) data + width * 4 * i, width * 4);
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}
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compressZlib(scanlines.str(), IDAT, compression);
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writeChunk(file, IDAT.str());
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}
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file.write("\x00\x00\x00\x00IEND\xae\x42\x60\x82", 12);
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return file.str();
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}
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