From 80d12dbedb67191a5eb3e4f3c36b04baed1f8afb Mon Sep 17 00:00:00 2001 From: hecks <42101236+hecktest@users.noreply.github.com> Date: Thu, 29 Jul 2021 05:10:10 +0200 Subject: Add a simple PNG image encoder with Lua API (#11485) * Add a simple PNG image encoder with Lua API Add ColorSpec to RGBA converter Make a safety wrapper for the encoder Create devtest examples Co-authored-by: hecktest <> Co-authored-by: sfan5 --- src/script/lua_api/l_util.cpp | 43 +++++++++++++++++++++++++++ src/script/lua_api/l_util.h | 6 ++++ src/util/CMakeLists.txt | 1 + src/util/png.cpp | 68 +++++++++++++++++++++++++++++++++++++++++++ src/util/png.h | 27 +++++++++++++++++ 5 files changed, 145 insertions(+) create mode 100755 src/util/png.cpp create mode 100755 src/util/png.h (limited to 'src') diff --git a/src/script/lua_api/l_util.cpp b/src/script/lua_api/l_util.cpp index 8de2d67c8..87436fce0 100644 --- a/src/script/lua_api/l_util.cpp +++ b/src/script/lua_api/l_util.cpp @@ -40,6 +40,7 @@ with this program; if not, write to the Free Software Foundation, Inc., #include "version.h" #include "util/hex.h" #include "util/sha1.h" +#include "util/png.h" #include #include @@ -497,6 +498,43 @@ int ModApiUtil::l_colorspec_to_colorstring(lua_State *L) return 0; } +// colorspec_to_bytes(colorspec) +int ModApiUtil::l_colorspec_to_bytes(lua_State *L) +{ + NO_MAP_LOCK_REQUIRED; + + video::SColor color(0); + if (read_color(L, 1, &color)) { + u8 colorbytes[4] = { + (u8) color.getRed(), + (u8) color.getGreen(), + (u8) color.getBlue(), + (u8) color.getAlpha(), + }; + lua_pushlstring(L, (const char*) colorbytes, 4); + return 1; + } + + return 0; +} + +// encode_png(w, h, data, level) +int ModApiUtil::l_encode_png(lua_State *L) +{ + NO_MAP_LOCK_REQUIRED; + + // The args are already pre-validated on the lua side. + u32 width = readParam(L, 1); + u32 height = readParam(L, 2); + const char *data = luaL_checklstring(L, 3, NULL); + s32 compression = readParam(L, 4); + + std::string out = encodePNG((const u8*)data, width, height, compression); + + lua_pushlstring(L, out.data(), out.size()); + return 1; +} + void ModApiUtil::Initialize(lua_State *L, int top) { API_FCT(log); @@ -532,6 +570,9 @@ void ModApiUtil::Initialize(lua_State *L, int top) API_FCT(get_version); API_FCT(sha1); API_FCT(colorspec_to_colorstring); + API_FCT(colorspec_to_bytes); + + API_FCT(encode_png); LuaSettings::create(L, g_settings, g_settings_path); lua_setfield(L, top, "settings"); @@ -557,6 +598,7 @@ void ModApiUtil::InitializeClient(lua_State *L, int top) API_FCT(get_version); API_FCT(sha1); API_FCT(colorspec_to_colorstring); + API_FCT(colorspec_to_bytes); } void ModApiUtil::InitializeAsync(lua_State *L, int top) @@ -585,6 +627,7 @@ void ModApiUtil::InitializeAsync(lua_State *L, int top) API_FCT(get_version); API_FCT(sha1); API_FCT(colorspec_to_colorstring); + API_FCT(colorspec_to_bytes); LuaSettings::create(L, g_settings, g_settings_path); lua_setfield(L, top, "settings"); diff --git a/src/script/lua_api/l_util.h b/src/script/lua_api/l_util.h index 6943a6afb..54d2be619 100644 --- a/src/script/lua_api/l_util.h +++ b/src/script/lua_api/l_util.h @@ -104,6 +104,12 @@ private: // colorspec_to_colorstring(colorspec) static int l_colorspec_to_colorstring(lua_State *L); + // colorspec_to_bytes(colorspec) + static int l_colorspec_to_bytes(lua_State *L); + + // encode_png(w, h, data, level) + static int l_encode_png(lua_State *L); + public: static void Initialize(lua_State *L, int top); static void InitializeAsync(lua_State *L, int top); diff --git a/src/util/CMakeLists.txt b/src/util/CMakeLists.txt index cd2e468d1..6bc97915f 100644 --- a/src/util/CMakeLists.txt +++ b/src/util/CMakeLists.txt @@ -15,4 +15,5 @@ set(UTIL_SRCS ${CMAKE_CURRENT_SOURCE_DIR}/string.cpp ${CMAKE_CURRENT_SOURCE_DIR}/srp.cpp ${CMAKE_CURRENT_SOURCE_DIR}/timetaker.cpp + ${CMAKE_CURRENT_SOURCE_DIR}/png.cpp PARENT_SCOPE) diff --git a/src/util/png.cpp b/src/util/png.cpp new file mode 100755 index 000000000..7ac2e94a1 --- /dev/null +++ b/src/util/png.cpp @@ -0,0 +1,68 @@ +/* +Minetest +Copyright (C) 2021 hecks + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details. + +You should have received a copy of the GNU Lesser General Public License along +with this program; if not, write to the Free Software Foundation, Inc., +51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +*/ + +#include "png.h" +#include +#include +#include +#include +#include "util/serialize.h" +#include "serialization.h" +#include "irrlichttypes.h" + +static void writeChunk(std::ostringstream &target, const std::string &chunk_str) +{ + assert(chunk_str.size() >= 4); + assert(chunk_str.size() - 4 < U32_MAX); + writeU32(target, chunk_str.size() - 4); // Write length minus the identifier + target << chunk_str; + writeU32(target, crc32(0,(const u8*)chunk_str.data(), chunk_str.size())); +} + +std::string encodePNG(const u8 *data, u32 width, u32 height, s32 compression) +{ + auto file = std::ostringstream(std::ios::binary); + file << "\x89PNG\r\n\x1a\n"; + + { + auto IHDR = std::ostringstream(std::ios::binary); + IHDR << "IHDR"; + writeU32(IHDR, width); + writeU32(IHDR, height); + // 8 bpp, color type 6 (RGBA) + IHDR.write("\x08\x06\x00\x00\x00", 5); + writeChunk(file, IHDR.str()); + } + + { + auto IDAT = std::ostringstream(std::ios::binary); + IDAT << "IDAT"; + auto scanlines = std::ostringstream(std::ios::binary); + for(u32 i = 0; i < height; i++) { + scanlines.write("\x00", 1); // Null predictor + scanlines.write((const char*) data + width * 4 * i, width * 4); + } + compressZlib(scanlines.str(), IDAT, compression); + writeChunk(file, IDAT.str()); + } + + file.write("\x00\x00\x00\x00IEND\xae\x42\x60\x82", 12); + + return file.str(); +} diff --git a/src/util/png.h b/src/util/png.h new file mode 100755 index 000000000..92387aef0 --- /dev/null +++ b/src/util/png.h @@ -0,0 +1,27 @@ +/* +Minetest +Copyright (C) 2021 hecks + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details. + +You should have received a copy of the GNU Lesser General Public License along +with this program; if not, write to the Free Software Foundation, Inc., +51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +*/ + +#pragma once + +#include +#include "irrlichttypes.h" + +/* Simple PNG encoder. Encodes an RGBA image with no predictors. + Returns a binary string. */ +std::string encodePNG(const u8 *data, u32 width, u32 height, s32 compression); -- cgit v1.2.3