From 03b0fa187bcc09873a61a3e6ec70f23db80bd97a Mon Sep 17 00:00:00 2001
From: DualFroz <me@dualfroz.com>
Date: Wed, 9 Sep 2026 16:45:09 +0200
Subject: [PATCH] feat: extend Selection

---
 core/src/Selection.cpp | 153 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 153 insertions(+)

diff --git a/core/src/Selection.cpp b/core/src/Selection.cpp
index a221f7a..bc08cab 100644
--- a/core/src/Selection.cpp
+++ b/core/src/Selection.cpp
@@ -153,3 +153,156 @@ SelectionMask SelectionMask::inverted() const {
     return flipped;
 }
 
+SelectionMask SelectionMask::dilated(int radius) const {
+    if (radius <= 0 || cellCount() == 0u) return *this;
+    Vec3i lo{corner.x - radius, corner.y - radius, corner.z - radius};
+    Vec3i hi{max().x + radius, max().y + radius, max().z + radius};
+    SelectionMask grown(lo, extentOf(lo, hi));
+    forEach([&](const Vec3i& cell) { grown.add(cell); });
+
+    for (int step = 0; step < radius; ++step) {
+        SelectionMask next = grown;
+        grown.forEach([&](const Vec3i& cell) {
+            for (const Vec3i& offset : faceOffsets) next.add(cell + offset);
+        });
+        grown = next;
+    }
+    return grown;
+}
+
+SelectionMask SelectionMask::eroded(int radius) const {
+    if (radius <= 0 || cellCount() == 0u) return *this;
+    SelectionMask shrunk = *this;
+    for (int step = 0; step < radius; ++step) {
+        SelectionMask next = shrunk;
+        shrunk.forEach([&](const Vec3i& cell) {
+            for (const Vec3i& offset : faceOffsets) {
+                if (!shrunk.contains(cell + offset)) {
+                    next.remove(cell);
+                    break;
+                }
+            }
+        });
+        shrunk = next;
+        if (shrunk.empty()) break;
+    }
+    return shrunk;
+}
+
+SelectionMask SelectionMask::outline() const {
+    SelectionMask shell(corner, size);
+    forEach([&](const Vec3i& cell) {
+        for (const Vec3i& offset : faceOffsets) {
+            if (!contains(cell + offset)) {
+                shell.add(cell);
+                break;
+            }
+        }
+    });
+    return shell;
+}
+
+SelectionMask SelectionMask::trimmed() const {
+    if (empty()) return SelectionMask{};
+    Vec3i lo = max();
+    Vec3i hi = corner;
+    forEach([&](const Vec3i& cell) {
+        lo = minCorner(lo, cell);
+        hi = maxCorner(hi, cell);
+    });
+    SelectionMask tight(lo, extentOf(lo, hi));
+    forEach([&](const Vec3i& cell) { tight.add(cell); });
+    return tight;
+}
+
+SelectionMask SelectionMask::shifted(const Vec3i& delta) const {
+    SelectionMask moved = *this;
+    moved.corner = corner + delta;
+    return moved;
+}
+
+bool SelectionMask::sameCells(const SelectionMask& other) const {
+    if (setCells != other.setCells) return false;
+    if (setCells == 0u) return true;
+    SelectionMask left = trimmed();
+    SelectionMask right = other.trimmed();
+    if (!(left.corner == right.corner) || !(left.size == right.size)) return false;
+    return left.words == right.words;
+}
+
+void SelectionMask::forEach(const std::function<void(const Vec3i&)>& visit) const {
+    if (setCells == 0u) return;
+    for (int y = 0; y < size.y; ++y)
+        for (int z = 0; z < size.z; ++z)
+            for (int x = 0; x < size.x; ++x) {
+                Vec3i cell{corner.x + x, corner.y + y, corner.z + z};
+                if (contains(cell)) visit(cell);
+            }
+}
+
+std::vector<Vec3i> SelectionMask::cells() const {
+    std::vector<Vec3i> out;
+    out.reserve(setCells);
+    forEach([&](const Vec3i& cell) { out.push_back(cell); });
+    return out;
+}
+
+uint32_t SelectionStats::countOf(Block block) const {
+    std::size_t index = static_cast<std::size_t>(block);
+    if (index >= histogram.size()) return 0u;
+    return histogram[index];
+}
+
+Block SelectionStats::dominantBlock() const {
+    Block best = Block::Air;
+    uint32_t bestCount = 0;
+    for (std::size_t index = 1; index < histogram.size(); ++index) {
+        if (histogram[index] > bestCount) {
+            bestCount = histogram[index];
+            best = static_cast<Block>(index);
+        }
+    }
+    return best;
+}
+
+std::size_t SelectionStats::distinctBlocks() const {
+    std::size_t distinct = 0;
+    for (uint32_t entry : histogram)
+        if (entry != 0u) ++distinct;
+    return distinct;
+}
+
+Selection Selection::derived(SelectionMask mask) {
+    Selection out;
+    out.kind = SelectionShape::Mask;
+    out.cells = std::move(mask);
+    return out;
+}
+
+Selection Selection::box(const Vec3i& cornerA, const Vec3i& cornerB) {
+    Vec3i lo = minCorner(cornerA, cornerB);
+    Vec3i hi = maxCorner(cornerA, cornerB);
+    Selection out;
+    out.kind = SelectionShape::Box;
+    out.cells = SelectionMask(lo, extentOf(lo, hi));
+    out.cells.fillAll();
+    return out;
+}
+
+Selection Selection::sphere(const Vec3i& center, int radius) {
+    Selection out = ellipsoid(center, {radius, radius, radius});
+    out.kind = SelectionShape::Sphere;
+    return out;
+}
+
+Selection Selection::ellipsoid(const Vec3i& center, const Vec3i& radii) {
+    int rx = std::max(radii.x, 0);
+    int ry = std::max(radii.y, 0);
+    int rz = std::max(radii.z, 0);
+    Vec3i lo{center.x - rx, center.y - ry, center.z - rz};
+    Vec3i hi{center.x + rx, center.y + ry, center.z + rz};
+
+    Selection out;
+    out.kind = SelectionShape::Ellipsoid;
+    out.cells = SelectionMask(lo, extentOf(lo, hi));
+