Add mipmap support to allow zooming out

4 files changed, 171 insertions, 42 deletions

diff --git a/src/Info.cpp b/src/Info.cpp
index 530d6b2..5d4bd71 100644
--- a/src/Info.cpp
+++ b/src/Info.cpp
@@ -34,7 +34,7 @@
 
 namespace MinedMap {
 
-void Info::writeJSON(const char *filename) {
+void Info::writeJSON(const char *filename) const {
 	const std::string tmpfile = std::string(filename) + ".tmp";
 
 	FILE *f = fopen(tmpfile.c_str(), "w");
@@ -44,28 +44,43 @@ void Info::writeJSON(const char *filename) {
 	}
 
 	fprintf(f, "{\n");
-	fprintf(f, "  \"info\" : {\n");
-	fprintf(f, "    \"minX\" : %i,\n", minX);
-	fprintf(f, "    \"maxX\" : %i,\n", maxX);
-	fprintf(f, "    \"minZ\" : %i,\n", minZ);
-	fprintf(f, "    \"maxZ\" : %i\n", maxZ);
-	fprintf(f, "  },\n");
-	fprintf(f, "  \"regions\" : [\n");
-
-	for (int z = minZ; z <= maxZ; z++) {
-		fprintf(f, "    [");
-
-		for (int x = minX; x <= maxX; x++) {
-			fprintf(f, "%s", regions.count(std::make_pair(x, z)) ? "true" : "false");
-
-			if (x < maxX)
-				fprintf(f, ", ");
+	fprintf(f, "  \"mipmaps\" : [\n");
+
+	for (size_t level = 0; level < regions.size(); level++) {
+		int minX, maxX, minZ, maxZ;
+		std::tie(minX, maxX, minZ, maxZ) = getBounds(level);
+
+		fprintf(f, "    {\n");
+		fprintf(f, "      \"info\" : {\n");
+		fprintf(f, "        \"minX\" : %i,\n", minX);
+		fprintf(f, "        \"maxX\" : %i,\n", maxX);
+		fprintf(f, "        \"minZ\" : %i,\n", minZ);
+		fprintf(f, "        \"maxZ\" : %i\n", maxZ);
+		fprintf(f, "      },\n");
+		fprintf(f, "      \"regions\" : [\n");
+
+		for (int z = minZ; z <= maxZ; z++) {
+			fprintf(f, "        [");
+
+			for (int x = minX; x <= maxX; x++) {
+				fprintf(f, "%s", regions[level].count(std::make_pair(x, z)) ? "true" : "false");
+
+				if (x < maxX)
+					fprintf(f, ", ");
+			}
+
+			if (z < maxZ)
+				fprintf(f, "],\n");
+			else
+				fprintf(f, "]\n");
 		}
 
-		if (z < maxZ)
-			fprintf(f, "],\n");
+		fprintf(f, "      ]\n");
+
+		if (level < regions.size() - 1)
+			fprintf(f, "    },\n");
 		else
-			fprintf(f, "]\n");
+			fprintf(f, "    }\n");
 	}
 
 	fprintf(f, "  ],\n");
diff --git a/src/Info.hpp b/src/Info.hpp
index 478e858..b7d040f 100644
--- a/src/Info.hpp
+++ b/src/Info.hpp
@@ -31,34 +31,52 @@
 #include <set>
 #include <tuple>
 #include <utility>
+#include <vector>
 
 
 namespace MinedMap {
 
 class Info {
 private:
-	std::set<std::pair<int, int>> regions;
-	int minX, maxX, minZ, maxZ;
+	std::vector<std::set<std::pair<int, int>>> regions;
+	std::vector<std::tuple<int, int, int, int>> bounds;
 
 	int32_t spawnX, spawnZ;
 
 public:
-	Info() : minX(INT_MAX), maxX(INT_MIN), minZ(INT_MAX), maxZ(INT_MIN), spawnX(0), spawnZ(0) {}
+	Info() : spawnX(0), spawnZ(0) {
+		addMipmapLevel();
+	}
+
+	std::tuple<int, int, int, int> getBounds(size_t level) const {
+		return bounds[level];
+	}
+
+	void addRegion(int x, int z, size_t level) {
+		regions[level].insert(std::make_pair(x, z));
 
-	void addRegion(int x, int z) {
-		regions.insert(std::make_pair(x, z));
+		std::tuple<int, int, int, int> &b = bounds[level];
+
+		if (x < std::get<0>(b)) std::get<0>(b) = x;
+		if (x > std::get<1>(b)) std::get<1>(b) = x;
+		if (z < std::get<2>(b)) std::get<2>(b) = z;
+		if (z > std::get<3>(b)) std::get<3>(b) = z;
+	}
+
+	void addMipmapLevel() {
+		regions.emplace_back();
+		bounds.emplace_back(INT_MAX, INT_MIN, INT_MAX, INT_MIN);
+	}
 
-		if (x < minX) minX = x;
-		if (x > maxX) maxX = x;
-		if (z < minZ) minZ = z;
-		if (z > maxZ) maxZ = z;
+	size_t getMipmapLevel() const {
+		return regions.size()-1;
 	}
 
 	void setSpawn(const std::pair<int32_t, int32_t> &v) {
 		std::tie(spawnX, spawnZ) = v;
 	}
 
-	void writeJSON(const char *filename);
+	void writeJSON(const char *filename) const;
 };
 
 }
diff --git a/src/MinedMap.cpp b/src/MinedMap.cpp
index 4ac39e1..8f548b6 100644
--- a/src/MinedMap.cpp
+++ b/src/MinedMap.cpp
@@ -35,6 +35,7 @@
 #include <cstring>
 #include <cstdlib>
 #include <iostream>
+#include <sstream>
 #include <system_error>
 
 #include <sys/types.h>
@@ -138,18 +139,26 @@ static void doRegion(const std::string &input, const std::string &output, const
 	}
 }
 
+template<typename T>
+static std::string format(const T &v) {
+	std::ostringstream s;
+
+	s << v;
+	return s.str();
+}
+
+static std::string formatTileName(int x, int z, const std::string &ext) {
+	std::ostringstream s;
+
+	s << "r." << x << "." << z << "." << ext;
+	return s.str();
+}
+
 static bool checkFilename(const char *name, int *x, int *z) {
 	if (std::sscanf(name, "r.%i.%i.mca", x, z) != 2)
 		return false;
 
-	size_t l = strlen(name) + 1;
-	char buf[l];
-	std::snprintf(buf, l, "r.%i.%i.mca", *x, *z);
-	if (std::memcmp(name, buf, l))
-		return false;
-
-	return true;
-
+	return (std::string(name) == formatTileName(*x, *z, "mca"));
 }
 
 static void makeDir(const std::string &name) {
@@ -157,7 +166,94 @@ static void makeDir(const std::string &name) {
 		throw std::system_error(errno, std::generic_category(), "unable to create directory " + name);
 }
 
-static void makeMipmaps(const std::string &outputdir, const Info &info) {
+static bool makeMipmap(const std::string &dir, size_t level, size_t x, size_t z, bool colored) {
+	bool ret = false;
+
+	std::string indir = dir + "/" + format(level-1) + "/";
+	std::string outdir = dir + "/" + format(level) + "/";
+
+	const std::string nw_str = indir + formatTileName(x*2, z*2, "png");
+	const std::string ne_str = indir + formatTileName(x*2+1, z*2, "png");
+	const std::string sw_str = indir + formatTileName(x*2, z*2+1, "png");
+	const std::string se_str = indir + formatTileName(x*2+1, z*2+1, "png");
+
+	const char *nw = nw_str.c_str();
+	const char *ne = ne_str.c_str();
+	const char *sw = sw_str.c_str();
+	const char *se = se_str.c_str();
+
+	struct timespec t;
+	struct stat s;
+	size_t count = 0;
+	for (auto name : {&nw, &ne, &sw, &se}) {
+		if (stat(*name, &s) < 0) {
+			*name = nullptr;
+			continue;
+		}
+
+		if (!count || s.st_mtim > t)
+			t = s.st_mtim;
+
+		count++;
+	}
+
+	std::string output = outdir + formatTileName(x, z, "png");
+	if (stat(output.c_str(), &s) == 0) {
+		ret = true;
+
+		if (!count || t <= s.st_mtim)
+			return ret;
+	}
+
+	if (!count)
+		return ret;
+
+	const std::string tmpfile = output + ".tmp";
+
+	try {
+		PNG::mipmap(tmpfile.c_str(), DIM, DIM, colored, nw, ne, sw, se);
+
+		struct timespec times[2] = {t, t};
+		if (utimensat(AT_FDCWD, tmpfile.c_str(), times, 0) < 0)
+			std::fprintf(stderr, "Warning: failed to set utime on %s: %s\n", tmpfile.c_str(), std::strerror(errno));
+
+		if (std::rename(tmpfile.c_str(), output.c_str()) < 0) {
+			std::fprintf(stderr, "Unable to save %s: %s\n", output.c_str(), std::strerror(errno));
+			unlink(tmpfile.c_str());
+		}
+	}
+	catch (const std::exception& ex) {
+		unlink(tmpfile.c_str());
+		throw;
+	}
+
+	return true;
+}
+
+static void makeMipmaps(const std::string &dir, Info *info) {
+	int minX, maxX, minZ, maxZ;
+	std::tie(minX, maxX, minZ, maxZ) = info->getBounds(0);
+
+	while (minX < -1 || maxX > 0 || minZ < -1 || maxZ > 0) {
+		info->addMipmapLevel();
+		size_t level = info->getMipmapLevel();
+		makeDir(dir + "/map/" + format(level));
+		makeDir(dir + "/light/" + format(level));
+
+		minX = (minX-1)/2;
+		maxX = maxX/2;
+		minZ = (minZ-1)/2;
+		maxZ = maxZ/2;
+
+		for (int x = minX; x <= maxX; x++) {
+			for (int z = minZ; z <= maxZ; z++) {
+				if (makeMipmap(dir + "/map", level, x, z, true))
+					info->addRegion(x, z, level);
+
+				makeMipmap(dir + "/light", level, x, z, false);
+			}
+		}
+	}
 }
 
 }
@@ -196,7 +292,7 @@ int main(int argc, char *argv[]) {
 		if (!checkFilename(entry->d_name, &x, &z))
 			continue;
 
-		info.addRegion(x, z);
+		info.addRegion(x, z, 0);
 
 		std::string name(entry->d_name), outname = name.substr(0, name.length()-3) + "png";
 		doRegion(regiondir + "/" + name, outputdir + "/map/0/" + outname, outputdir + "/light/0/" + outname);
@@ -207,7 +303,7 @@ int main(int argc, char *argv[]) {
 	World::Level level((inputdir + "/level.dat").c_str());
 	info.setSpawn(level.getSpawn());
 
-	makeMipmaps(outputdir, info);
+	makeMipmaps(outputdir, &info);
 
 	info.writeJSON((outputdir + "/info.json").c_str());
 
diff --git a/src/PNG.cpp b/src/PNG.cpp
index 9edf88c..f56c870 100644
--- a/src/PNG.cpp
+++ b/src/PNG.cpp
@@ -147,7 +147,7 @@ void mipmap(const char *output, size_t width, size_t height, bool colored, const
 	readScaled(data, 0, height/2, sw, width, height, colored);
 	readScaled(data, width/2, height/2, se, width, height, colored);
 
-	write(output, data, width, height, true);
+	write(output, data, width, height, colored);
 }
 
 }