ifcviewer: per-element visibility (H / Shift+H / Alt+H)

Adds VisibilityState, a CPU-only sibling to SelectionState. It owns the canonical hidden-id set plus a flat per-object_id byte vector that the cull's hot path queries inline (bounds check + byte load + compare per surviving instance). Hidden elements never reach the visible[] SSBO so they don't draw or pick — matching Blender/CAD convention. ViewportWindow registers every streamed and sidecar-cached object_id with the new state, resets it on clearScene, and connects the changed signal to invalidate cached cull state. Three convenience verbs: hideSelectedElements (union into hidden), isolateSelectedElements (replace hidden with live-object_ids minus selection, skipping model-hidden models so element-hide doesn't pile on top of model-hide), and showAllElements (clears the override; model-hidden models stay hidden, per the user's spec). Bound in the View menu: H hide, Shift+H isolate, Alt+H show all. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-09-20 23:36:20 +00:00 · 2026-05-11 07:33:09 +10:00
parent 742561c56d
commit 1c598a981e
5 changed files with 269 additions and 3 deletions
@@ -0,0 +1,89 @@
+/********************************************************************************
+ *                                                                              *
+ * This file is part of IfcOpenShell.                                           *
+ *                                                                              *
+ * IfcOpenShell is free software: you can redistribute it and/or modify         *
+ * it under the terms of the Lesser GNU General Public License as published by  *
+ * the Free Software Foundation, either version 3.0 of the License, or          *
+ * (at your option) any later version.                                          *
+ *                                                                              *
+ * IfcOpenShell 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                 *
+ * Lesser GNU General Public License for more details.                          *
+ *                                                                              *
+ * You should have received a copy of the Lesser GNU General Public License     *
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.         *
+ *                                                                              *
+ ********************************************************************************/
+
+#ifndef IFCVIEWER_VISIBILITY_H
+#define IFCVIEWER_VISIBILITY_H
+
+#include <QObject>
+
+#include <cstdint>
+#include <unordered_set>
+#include <vector>
+
+// Per-element visibility state, owned by ViewportWindow.  Independent of
+// the per-model `hidden` flag — model-level hiding still wins (a hidden
+// model never draws regardless of its elements' visibility).  This class
+// only tracks element-level overrides on top.
+//
+// Lookup is hot — the CPU cull queries `isHidden(object_id)` for every
+// surviving instance — so the canonical set is mirrored into a flat
+// per-id byte vector indexed directly by object_id.  Ownership is purely
+// CPU: nothing on the GPU reads visibility, the cull just skips hidden
+// instances before they reach the visible[] SSBO.
+class VisibilityState : public QObject {
+    Q_OBJECT
+public:
+    explicit VisibilityState(QObject* parent = nullptr);
+
+    // Tell the manager about a newly added object_id so the flag vector
+    // can grow ahead of the next cull.  Cheap when the id fits already.
+    void noteObjectId(uint32_t id);
+
+    // Drop everything — clears the hidden set.  Called from clearScene.
+    void reset();
+
+    // ---- Mutation ----
+    //
+    // hideObjects: union into the hidden set.
+    // showObjects: subtract from the hidden set.
+    // setHidden:   replace the hidden set wholesale (used by isolate).
+    // showAll:     equivalent to setHidden({}).
+    void hideObjects(const std::unordered_set<uint32_t>& ids);
+    void showObjects(const std::unordered_set<uint32_t>& ids);
+    void setHidden(const std::unordered_set<uint32_t>& ids);
+    void showAll();
+
+    // ---- Hot-path query ----
+    //
+    // Inline so the cull's `if (visibility_.isHidden(...)) return;`
+    // compiles to a bounds check + a byte load + a compare.
+    bool isHidden(uint32_t id) const {
+        return id < cpu_flags_.size() && cpu_flags_[id] != 0;
+    }
+
+    // ---- Accessors ----
+    bool empty() const { return hidden_ids_.empty(); }
+    size_t size() const { return hidden_ids_.size(); }
+    const std::unordered_set<uint32_t>& hiddenIds() const { return hidden_ids_; }
+
+signals:
+    // Emitted on any mutation that changes the hidden set.  Consumers
+    // (the viewport) connect to invalidate cached cull state and
+    // requestUpdate.
+    void changed();
+
+private:
+    // Recompute cpu_flags_ from hidden_ids_.  Cheap: O(|cpu_flags_|).
+    void rebuildFlags();
+
+    std::unordered_set<uint32_t> hidden_ids_;
+    std::vector<uint8_t>         cpu_flags_;
+};
+
+#endif // IFCVIEWER_VISIBILITY_H