egutierrez
144b15f0ce
Previously the cycle validator rejected any link whose source had a vector index >= target's, which silently killed legitimate connections between nodes added in the wrong drop order. Switch to a DFS over source_ids: an edge from->to creates a cycle iff `from` already (transitively) depends on `to`. topo_sort runs after each topology change so the vector ends up in a consistent order regardless of how nodes were inserted. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
450 lines
18 KiB
C++
450 lines
18 KiB
C++
#include "gfx/dag_node_editor.h"
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#include "gfx/dag_catalog.h"
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#include "imgui.h"
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#include "imgui_node_editor.h"
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#include <algorithm>
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#include <cstdio>
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#include <functional>
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#include <queue>
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#include <string>
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#include <unordered_map>
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#include <unordered_set>
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#include <vector>
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namespace ed = ax::NodeEditor;
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namespace fn::gfx {
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static constexpr int MAX_NODES = 16;
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static ed::EditorContext* s_ctx = nullptr;
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static uint32_t s_next_uid = 1;
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static std::unordered_set<uint32_t> s_positioned;
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// ── ID encoding ──────────────────────────────────────────────────────────────
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// node id = editor_uid
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// output pin id = (editor_uid << 8) | 0
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// input pin id = (editor_uid << 8) | (slot + 1) slot 0..3
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// link id = (from_node_uid << 20) | (to_node_uid << 8) | slot
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static uintptr_t node_id(uint32_t uid) {
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return static_cast<uintptr_t>(uid);
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}
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static uintptr_t output_pin_id(uint32_t uid) {
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return (static_cast<uintptr_t>(uid) << 8) | 0u;
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}
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static uintptr_t input_pin_id(uint32_t uid, int slot) {
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return (static_cast<uintptr_t>(uid) << 8) | static_cast<uintptr_t>(slot + 1);
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}
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static uintptr_t link_id(uint32_t from_uid, uint32_t to_uid, int slot) {
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return (static_cast<uintptr_t>(from_uid) << 20)
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| (static_cast<uintptr_t>(to_uid) << 8)
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| static_cast<uintptr_t>(slot);
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}
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// Decode pin id back
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static bool is_output_pin(uintptr_t id) { return (id & 0xFF) == 0; }
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static uint32_t uid_from_pin(uintptr_t id) { return static_cast<uint32_t>(id >> 8); }
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static int slot_from_input_pin(uintptr_t id) { return static_cast<int>(id & 0xFF) - 1; }
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static int find_by_uid(const std::vector<DagStep>& p, uint32_t uid) {
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for (int i = 0; i < static_cast<int>(p.size()); ++i) {
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if (p[static_cast<size_t>(i)].editor_uid == uid) return i;
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}
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return -1;
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}
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static int find_by_id(const std::vector<DagStep>& p, const std::string& id) {
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for (int i = 0; i < static_cast<int>(p.size()); ++i) {
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if (p[static_cast<size_t>(i)].id == id) return i;
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}
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return -1;
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}
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static ImVec4 kind_color(DagKind kind) {
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switch (kind) {
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case DagKind::Gen: return ImVec4(0.25f, 0.55f, 0.90f, 1.0f);
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case DagKind::Op: return ImVec4(0.65f, 0.40f, 0.90f, 1.0f);
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case DagKind::Blend: return ImVec4(0.90f, 0.65f, 0.15f, 1.0f);
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case DagKind::Output: return ImVec4(0.85f, 0.25f, 0.25f, 1.0f);
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}
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return ImVec4(1, 1, 1, 1);
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}
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// Topological sort using Kahn's algorithm.
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// Returns false if a cycle is detected (should not happen — BeginCreate rejects cycles).
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static bool topo_sort(std::vector<DagStep>& pipeline) {
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int n = static_cast<int>(pipeline.size());
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if (n == 0) return true;
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// Build adjacency: edge from src -> dst if dst.source_ids[k] == src.id
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std::unordered_map<std::string, int> id_to_idx;
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for (int i = 0; i < n; ++i) id_to_idx[pipeline[static_cast<size_t>(i)].id] = i;
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std::vector<int> in_degree(static_cast<size_t>(n), 0);
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std::vector<std::vector<int>> adj(static_cast<size_t>(n));
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for (int i = 0; i < n; ++i) {
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const DagStep& s = pipeline[static_cast<size_t>(i)];
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const DagNodeDef* def = dag_find(s.name);
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int ni = def ? def->num_inputs : 0;
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for (int k = 0; k < ni; ++k) {
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const std::string& sid = s.source_ids[static_cast<size_t>(k)];
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if (sid.empty()) continue;
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auto it = id_to_idx.find(sid);
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if (it == id_to_idx.end()) continue;
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int src = it->second;
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adj[static_cast<size_t>(src)].push_back(i);
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in_degree[static_cast<size_t>(i)]++;
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}
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}
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std::queue<int> q;
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for (int i = 0; i < n; ++i) {
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if (in_degree[static_cast<size_t>(i)] == 0) q.push(i);
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}
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std::vector<int> order;
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order.reserve(static_cast<size_t>(n));
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while (!q.empty()) {
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int u = q.front(); q.pop();
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order.push_back(u);
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for (int v : adj[static_cast<size_t>(u)]) {
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if (--in_degree[static_cast<size_t>(v)] == 0) q.push(v);
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}
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}
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if (static_cast<int>(order.size()) != n) return false; // cycle
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std::vector<DagStep> sorted;
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sorted.reserve(static_cast<size_t>(n));
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for (int idx : order) sorted.push_back(pipeline[static_cast<size_t>(idx)]);
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// Force Output nodes to the back so all their dependencies live at smaller
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// indices (compiler and cycle validator search strictly before the target).
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std::stable_partition(sorted.begin(), sorted.end(), [](const DagStep& s) {
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const DagNodeDef* d = dag_find(s.name);
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return !(d && d->kind == DagKind::Output);
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});
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pipeline = std::move(sorted);
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return true;
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}
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bool dag_node_editor(std::vector<DagStep>& pipeline) {
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bool changed = false;
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// Ensure UIDs are assigned (e.g. for nodes created before this editor was active)
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for (auto& step : pipeline) {
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if (step.editor_uid == 0) {
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step.editor_uid = s_next_uid++;
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}
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}
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// Create context on first call
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if (!s_ctx) {
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ed::Config cfg;
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cfg.SettingsFile = nullptr; // no disk persistence
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s_ctx = ed::CreateEditor(&cfg);
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}
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// Palette drop: detect without a capturing target (an InvisibleButton would
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// steal clicks from the node editor). Observe the active drag-drop payload
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// and, if the mouse is over this window and the user releases LMB, queue an
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// add at that canvas position.
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static std::string s_pending_add_name;
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static ImVec2 s_pending_add_pos(0, 0);
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static bool s_pending_add = false;
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const bool window_hovered = ImGui::IsWindowHovered(
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ImGuiHoveredFlags_ChildWindows | ImGuiHoveredFlags_AllowWhenBlockedByActiveItem);
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if (window_hovered) {
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if (const ImGuiPayload* p = ImGui::GetDragDropPayload()) {
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if (p->IsDataType("DAG_NODE_TYPE") && ImGui::IsMouseReleased(ImGuiMouseButton_Left)) {
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s_pending_add_name.assign(static_cast<const char*>(p->Data),
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static_cast<size_t>(p->DataSize));
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s_pending_add_pos = ImGui::GetMousePos();
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s_pending_add = true;
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}
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}
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}
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ed::SetCurrentEditor(s_ctx);
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ed::Begin("dag_editor", ImVec2(0.0f, 0.0f));
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if (s_pending_add) {
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const DagNodeDef* def = dag_find(s_pending_add_name);
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if (def && static_cast<int>(pipeline.size()) < MAX_NODES) {
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uint32_t uid = s_next_uid++;
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DagStep step;
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step.id = "n" + std::to_string(uid);
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step.name = def->name;
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step.params = def->param_defaults;
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step.editor_uid = uid;
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ImVec2 canvas_pos = ed::ScreenToCanvas(s_pending_add_pos);
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step.editor_pos_x = canvas_pos.x;
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step.editor_pos_y = canvas_pos.y;
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// Insert before the Output node so the Output stays at the back;
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// otherwise new nodes can never be wired into it (compiler and
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// cycle check only search indices strictly before the target).
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auto insert_it = pipeline.end();
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for (auto it = pipeline.begin(); it != pipeline.end(); ++it) {
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const DagNodeDef* d = dag_find(it->name);
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if (d && d->kind == DagKind::Output) { insert_it = it; break; }
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}
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pipeline.insert(insert_it, step);
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changed = true;
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}
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s_pending_add = false;
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}
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// ── Draw nodes ───────────────────────────────────────────────────────────
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for (int i = 0; i < static_cast<int>(pipeline.size()); ++i) {
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DagStep& step = pipeline[static_cast<size_t>(i)];
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const DagNodeDef* def = dag_find(step.name);
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if (!def) continue;
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ImVec4 col = kind_color(def->kind);
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// Initial position only — after that, the editor owns the node's position
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// and user drags must not be overwritten.
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if (s_positioned.find(step.editor_uid) == s_positioned.end()) {
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if (step.editor_pos_x == 0.0f && step.editor_pos_y == 0.0f) {
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step.editor_pos_x = 50.0f + static_cast<float>(i) * 220.0f;
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step.editor_pos_y = 100.0f;
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}
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ed::SetNodePosition(ed::NodeId(node_id(step.editor_uid)),
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ImVec2(step.editor_pos_x, step.editor_pos_y));
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s_positioned.insert(step.editor_uid);
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}
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ed::BeginNode(ed::NodeId(node_id(step.editor_uid)));
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// Header
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ImGui::PushStyleColor(ImGuiCol_Text, col);
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ImGui::TextUnformatted(def->label.c_str());
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ImGui::PopStyleColor();
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ImGui::Dummy(ImVec2(0, 2));
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// Input pins (left column) + controls (middle) + output pin (right)
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// We use a simple layout: input pins vertically, then controls, then output pin
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int ni = def->num_inputs;
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// Input pins
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for (int k = 0; k < ni; ++k) {
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ed::BeginPin(ed::PinId(input_pin_id(step.editor_uid, k)), ed::PinKind::Input);
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char lbl[16];
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std::snprintf(lbl, sizeof(lbl), "-> in%d", k);
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ImGui::TextUnformatted(lbl);
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ed::EndPin();
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}
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if (ni == 0) {
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// Gen: no inputs, push a small placeholder so layout is consistent
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ImGui::Dummy(ImVec2(4, 4));
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}
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// Controls
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ImGui::PushID(static_cast<int>(step.editor_uid));
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for (size_t ci = 0; ci < def->controls.size(); ++ci) {
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const DagControl& ctrl = def->controls[ci];
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ImGui::SetNextItemWidth(150.0f);
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char uid_lbl[64];
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std::snprintf(uid_lbl, sizeof(uid_lbl), "%s##%u%zu", ctrl.label.c_str(), step.editor_uid, ci);
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if (ctrl.kind == DagControl::Kind::Slider) {
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int pidx = ctrl.param_idx[0];
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if (pidx >= 0 && pidx < 4) {
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ImGui::SliderFloat(uid_lbl, &step.params[static_cast<size_t>(pidx)], ctrl.min, ctrl.max);
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}
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} else if (ctrl.kind == DagControl::Kind::XY) {
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int px = ctrl.param_idx[0], py = ctrl.param_idx[1];
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if (px >= 0 && px < 4 && py >= 0 && py < 4 && py == px + 1) {
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ImGui::SliderFloat2(uid_lbl, &step.params[static_cast<size_t>(px)], ctrl.min, ctrl.max);
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}
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} else if (ctrl.kind == DagControl::Kind::Color) {
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int pr = ctrl.param_idx[0];
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if (pr >= 0 && pr + 2 < 4) {
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// Suspend the node editor while the color picker popup is
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// open so its clicks don't reach the canvas (and so the
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// popup isn't clipped to the node bounds).
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ed::Suspend();
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ImGui::ColorEdit3(uid_lbl, &step.params[static_cast<size_t>(pr)],
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ImGuiColorEditFlags_NoInputs |
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ImGuiColorEditFlags_NoLabel |
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ImGuiColorEditFlags_AlphaBar);
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ed::Resume();
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}
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}
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}
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ImGui::PopID();
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// Output pin (skip for the terminal Output node — it has no output)
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if (def->kind != DagKind::Output) {
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ImGui::Dummy(ImVec2(0, 2));
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ed::BeginPin(ed::PinId(output_pin_id(step.editor_uid)), ed::PinKind::Output);
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ImGui::Text("out ->");
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ed::EndPin();
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}
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ed::EndNode();
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}
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// ── Draw existing links ──────────────────────────────────────────────────
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for (int i = 0; i < static_cast<int>(pipeline.size()); ++i) {
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const DagStep& step = pipeline[static_cast<size_t>(i)];
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const DagNodeDef* def = dag_find(step.name);
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if (!def) continue;
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for (int k = 0; k < def->num_inputs; ++k) {
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const std::string& sid = step.source_ids[static_cast<size_t>(k)];
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if (sid.empty()) continue;
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int src_idx = find_by_id(pipeline, sid);
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if (src_idx < 0) continue;
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uint32_t src_uid = pipeline[static_cast<size_t>(src_idx)].editor_uid;
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ed::Link(ed::LinkId(link_id(src_uid, step.editor_uid, k)),
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ed::PinId(output_pin_id(src_uid)),
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ed::PinId(input_pin_id(step.editor_uid, k)));
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}
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}
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// ── Handle link creation ─────────────────────────────────────────────────
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if (ed::BeginCreate()) {
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ed::PinId start_pin, end_pin;
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if (ed::QueryNewLink(&start_pin, &end_pin)) {
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uintptr_t sp = start_pin.Get();
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uintptr_t ep = end_pin.Get();
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// Normalise: start must be output, end must be input
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if (!is_output_pin(sp) && is_output_pin(ep)) {
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std::swap(sp, ep);
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}
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bool valid = is_output_pin(sp) && !is_output_pin(ep);
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if (valid) {
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uint32_t from_uid = uid_from_pin(sp);
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uint32_t to_uid = uid_from_pin(ep);
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int slot = slot_from_input_pin(ep);
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int from_idx = find_by_uid(pipeline, from_uid);
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int to_idx = find_by_uid(pipeline, to_uid);
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// Real cycle check: would the new edge from->to introduce a path
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// from `from` back to itself? It does iff `from` already (transitively)
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// depends on `to`. We walk source_ids of `from` and reject if we
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// ever hit `to`. Vector index order is irrelevant — topo_sort runs
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// at end-of-frame and reorders the pipeline.
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bool cycle = false;
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if (from_uid == to_uid) {
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cycle = true;
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} else if (from_idx >= 0 && to_idx >= 0) {
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const std::string to_id = pipeline[static_cast<size_t>(to_idx)].id;
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std::function<bool(const std::string&)> depends_on_to;
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depends_on_to = [&](const std::string& node_id) -> bool {
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if (node_id == to_id) return true;
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int idx = -1;
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for (int i = 0; i < static_cast<int>(pipeline.size()); ++i) {
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if (pipeline[static_cast<size_t>(i)].id == node_id) { idx = i; break; }
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}
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if (idx < 0) return false;
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const DagStep& s = pipeline[static_cast<size_t>(idx)];
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const DagNodeDef* d = dag_find(s.name);
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int n = d ? d->num_inputs : 0;
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for (int k = 0; k < n; ++k) {
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const std::string& sid = s.source_ids[static_cast<size_t>(k)];
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if (!sid.empty() && depends_on_to(sid)) return true;
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}
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return false;
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};
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cycle = depends_on_to(pipeline[static_cast<size_t>(from_idx)].id);
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}
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if (cycle) {
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ed::RejectNewItem(ImVec4(1, 0.3f, 0.3f, 1));
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valid = false;
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}
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if (valid && from_idx >= 0 && to_idx >= 0 && slot >= 0) {
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if (ed::AcceptNewItem()) {
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pipeline[static_cast<size_t>(to_idx)].source_ids[static_cast<size_t>(slot)] =
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pipeline[static_cast<size_t>(from_idx)].id;
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changed = true;
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}
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}
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} else {
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ed::RejectNewItem(ImVec4(0.5f, 0.5f, 0.5f, 1));
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}
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}
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}
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ed::EndCreate();
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// ── Handle deletion ──────────────────────────────────────────────────────
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if (ed::BeginDelete()) {
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ed::LinkId del_lid;
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while (ed::QueryDeletedLink(&del_lid)) {
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if (ed::AcceptDeletedItem()) {
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uintptr_t raw = del_lid.Get();
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uint32_t to_uid = static_cast<uint32_t>((raw >> 8) & 0xFFF);
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int slot = static_cast<int>(raw & 0xFF);
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int to_idx = find_by_uid(pipeline, to_uid);
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if (to_idx >= 0 && slot < 4) {
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pipeline[static_cast<size_t>(to_idx)].source_ids[static_cast<size_t>(slot)].clear();
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changed = true;
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}
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}
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}
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ed::NodeId del_nid;
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while (ed::QueryDeletedNode(&del_nid)) {
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uint32_t uid = static_cast<uint32_t>(del_nid.Get());
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int idx = find_by_uid(pipeline, uid);
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// Refuse to delete the Output node (it's the sink)
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const DagNodeDef* ddef = (idx >= 0) ? dag_find(pipeline[static_cast<size_t>(idx)].name) : nullptr;
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if (ddef && ddef->kind == DagKind::Output) {
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ed::RejectDeletedItem();
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continue;
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}
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if (ed::AcceptDeletedItem()) {
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if (idx >= 0) {
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const std::string& del_step_id = pipeline[static_cast<size_t>(idx)].id;
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for (auto& step : pipeline) {
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for (auto& sid : step.source_ids) {
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if (sid == del_step_id) sid.clear();
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}
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}
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pipeline.erase(pipeline.begin() + idx);
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changed = true;
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}
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}
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}
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}
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ed::EndDelete();
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// ── Save node positions back to steps ────────────────────────────────────
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for (auto& step : pipeline) {
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auto pos = ed::GetNodePosition(ed::NodeId(node_id(step.editor_uid)));
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step.editor_pos_x = pos.x;
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step.editor_pos_y = pos.y;
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}
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|
|
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ed::End();
|
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ed::SetCurrentEditor(nullptr);
|
|
|
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// ── Topological sort after topology change ───────────────────────────────
|
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if (changed) {
|
|
if (!topo_sort(pipeline)) {
|
|
// Cycle detected — should not happen given BeginCreate validation
|
|
// but log a warning and leave order as-is
|
|
std::fprintf(stderr, "dag_node_editor: cycle detected, skipping topo sort\n");
|
|
}
|
|
}
|
|
|
|
return changed;
|
|
}
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|
|
|
void dag_node_editor_destroy() {
|
|
if (s_ctx) {
|
|
ed::DestroyEditor(s_ctx);
|
|
s_ctx = nullptr;
|
|
}
|
|
}
|
|
|
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} // namespace fn::gfx
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