Refactor texture overrides and add new features (#9600)

* Refactor texture overrides, and add new features:

- Texture overrides can support multiple targets in one line
- Texture override files can have comment lines
- Item images/wield images can be overridden

* Formatting changes

* Address soime feedback

- Pass vectors by const reference
- Log syntax errors as warnings
- Remove 'C' prefix from TextureOverrideSource

* Simplify override target checks with an inline helper function

* make linter happy

* Apply feedback suggestions

Co-Authored-By: rubenwardy <rw@rubenwardy.com>

* Remove remaining != 0 checks

* Update copyright notice

Co-authored-by: sfan5 <sfan5@live.de>
Co-authored-by: rubenwardy <rw@rubenwardy.com>

src/texture_override.cpp

@@ -0,0 +1,120 @@
+/*
+Minetest
+Copyright (C) 2020 Hugues Ross <hugues.ross@gmail.com>
+
+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 "texture_override.h"
+
+#include "log.h"
+#include "util/string.h"
+#include <algorithm>
+#include <fstream>
+
+TextureOverrideSource::TextureOverrideSource(std::string filepath)
+{
+	std::ifstream infile(filepath.c_str());
+	std::string line;
+	int line_index = 0;
+	while (std::getline(infile, line)) {
+		line_index++;
+
+		// Also trim '\r' on DOS-style files
+		line = trim(line);
+
+		// Ignore empty lines and comments
+		if (line.empty() || line[0] == '#')
+			continue;
+
+		std::vector<std::string> splitted = str_split(line, ' ');
+		if (splitted.size() != 3) {
+			warningstream << filepath << ":" << line_index
+					<< " Syntax error in texture override \"" << line
+					<< "\": Expected 3 arguments, got " << splitted.size()
+					<< std::endl;
+			continue;
+		}
+
+		TextureOverride texture_override = {};
+		texture_override.id = splitted[0];
+		texture_override.texture = splitted[2];
+
+		// Parse the target mask
+		std::vector<std::string> targets = str_split(splitted[1], ',');
+		for (const std::string &target : targets) {
+			if (target == "top")
+				texture_override.target |= static_cast<u8>(OverrideTarget::TOP);
+			else if (target == "bottom")
+				texture_override.target |= static_cast<u8>(OverrideTarget::BOTTOM);
+			else if (target == "left")
+				texture_override.target |= static_cast<u8>(OverrideTarget::LEFT);
+			else if (target == "right")
+				texture_override.target |= static_cast<u8>(OverrideTarget::RIGHT);
+			else if (target == "front")
+				texture_override.target |= static_cast<u8>(OverrideTarget::FRONT);
+			else if (target == "back")
+				texture_override.target |= static_cast<u8>(OverrideTarget::BACK);
+			else if (target == "inventory")
+				texture_override.target |= static_cast<u8>(OverrideTarget::INVENTORY);
+			else if (target == "wield")
+				texture_override.target |= static_cast<u8>(OverrideTarget::WIELD);
+			else if (target == "sides")
+				texture_override.target |= static_cast<u8>(OverrideTarget::SIDES);
+			else if (target == "all" || target == "*")
+				texture_override.target |= static_cast<u8>(OverrideTarget::ALL_FACES);
+			else {
+				// Report invalid target
+				warningstream << filepath << ":" << line_index
+						<< " Syntax error in texture override \"" << line
+						<< "\": Unknown target \"" << target << "\""
+						<< std::endl;
+			}
+		}
+
+		// If there are no valid targets, skip adding this override
+		if (texture_override.target == static_cast<u8>(OverrideTarget::INVALID)) {
+			continue;
+		}
+
+		m_overrides.push_back(texture_override);
+	}
+}
+
+//! Get all overrides that apply to item definitions
+std::vector<TextureOverride> TextureOverrideSource::getItemTextureOverrides()
+{
+	std::vector<TextureOverride> found_overrides;
+
+	for (const TextureOverride &texture_override : m_overrides) {
+		if (texture_override.hasTarget(OverrideTarget::ITEM_TARGETS))
+			found_overrides.push_back(texture_override);
+	}
+
+	return found_overrides;
+}
+
+//! Get all overrides that apply to node definitions
+std::vector<TextureOverride> TextureOverrideSource::getNodeTileOverrides()
+{
+	std::vector<TextureOverride> found_overrides;
+
+	for (const TextureOverride &texture_override : m_overrides) {
+		if (texture_override.hasTarget(OverrideTarget::ALL_FACES))
+			found_overrides.push_back(texture_override);
+	}
+
+	return found_overrides;
+}