[jasper/world/studio] Make selection tracking safer, allow clearing selection

src/jasper/modules/world/src/studio/worldeditor/worldeditor-imgui.cpp

@@ -255,12 +255,17 @@ void WorldEditorImGui::handleSelection(ox::Size const&paneSz, float fbPaneScale)
 		                   && inside(fbPos.x, 0, paneSz.width)
 		                   && inside(fbPos.y, 0, paneSz.height);
 		auto const scaledViewSz = static_cast<ox::Vec2>(m_view.drawSize()) * fbPaneScale;
-		m_selection.updateCursorPoint(fbPtToTileAddr(fbPos, scaledViewSz), startSel);
-		if (m_selection.selectionOngoing()) {
-			m_view.setSelection(m_selection.selection());
+		m_selTracker.updateCursorPoint(fbPtToTileAddr(fbPos, scaledViewSz), startSel);
+		if (m_selTracker.selectionOngoing()) {
+			m_selection.emplace(m_selTracker.selection());
+			m_view.setSelection(*m_selection);
 		}
 	} else if (io.MouseReleased[0]) {
-		m_selection.finishSelection();
+		m_selTracker.finishSelection();
+	}
+	if (io.KeyCtrl && io.KeysDown[ImGuiKey_G]) {
+		m_selection.reset();
+		m_view.clearSelection();
 	}
 }
 
@@ -277,7 +282,7 @@ ox::Error WorldEditorImGui::handleDrop(float fbPaneScale) noexcept {
 	if (tileAddr.x < m_doc.columns && tileAddr.y < m_doc.rows) {
 		ox::Vector<ModifyTilesCommand::Mod> mods;
 		if (tileSelected(tileAddr)) {
-			studio::iterateSelection(m_selection.selection(), [&](int32_t x, int32_t y) {
+			studio::iterateSelection(*m_selection, [&](int32_t x, int32_t y) {
 				mods.emplace_back(ModifyTilesCommand::Mod{
 					.layer = m_activeLayer,
 					.tileAddr = {x, y},
@@ -342,7 +347,10 @@ ox::Error WorldEditorImGui::undoStackChanged(studio::UndoCommand const*) {
 }
 
 bool WorldEditorImGui::tileSelected(ox::Point const&pt) const noexcept {
-	auto const sel = m_selection.selection();
+	if (!m_selection) {
+		return false;
+	}
+	auto const&sel = *m_selection;
 	return inside(pt.x, sel.a.x, sel.b.x) && inside(pt.y, sel.a.y, sel.b.y);
 }
 

src/jasper/modules/world/src/studio/worldeditor/worldeditor-imgui.hpp

@@ -19,7 +19,8 @@ namespace jasper::world {
 class WorldEditorImGui: public studio::Editor {
 
 	private:
-		studio::SelectionTracker m_selection;
+		studio::SelectionTracker m_selTracker;
+		ox::Optional<studio::Selection> m_selection;
 		uint8_t m_activeLayer{};
 		studio::StudioContext &m_sctx;
 		studio::ig::FilePicker m_objSetPicker{

src/jasper/modules/world/src/studio/worldeditor/worldeditorview.cpp

@@ -37,12 +37,16 @@ void WorldEditorView::draw(ox::Size const&targetSz) noexcept {
 	m_highlighter.draw();
 }
 
-void WorldEditorView::setSelection(studio::Selection const&sel) noexcept {
+void WorldEditorView::clearSelection() noexcept {
 	if (m_selection) {
 		studio::iterateSelection(*m_selection, [this](int32_t x, int32_t y) {
 			std::ignore = m_highlighter.setTileHighlight({x, y}, false);
 		});
 	}
+}
+
+void WorldEditorView::setSelection(studio::Selection const&sel) noexcept {
+	clearSelection();
 	m_selection.emplace(sel);
 	studio::iterateSelection(*m_selection, [this](int32_t x, int32_t y) {
 		std::ignore = m_highlighter.setTileHighlight({x, y}, true);

src/jasper/modules/world/src/studio/worldeditor/worldeditorview.hpp

@@ -39,6 +39,8 @@ class WorldEditorView {
 
 		void draw(ox::Size const&targetSz) noexcept;
 
+		void clearSelection() noexcept;
+
 		void setSelection(studio::Selection const&sel) noexcept;
 
 		[[nodiscard]]