Extending the Add Node Menu

Overview

This example demonstrates how to extend the "Add Node" submenu that appears in the hierarchy context menu and World > Spawn Node. You can add items to existing categories (3D, Widget, Other) or create entirely new categories.

Files

package.json

{
    "name": "Custom Node Types Addon",
    "author": "Polyphase Examples",
    "description": "Adds custom node types to the Add Node menu.",
    "version": "1.0.0",
    "tags": ["editor", "example"],
    "native": {
        "target": "editor",
        "sourceDir": "Source",
        "binaryName": "customnodetypesaddon",
        "apiVersion": 2
    }
}

Source/CustomNodeTypesAddon.cpp

#include "Plugins/PolyphasePluginAPI.h"
#include "Plugins/PolyphaseEngineAPI.h"

#if EDITOR
#include "Plugins/EditorUIHooks.h"
#include "imgui.h"
#endif

static PolyphaseEngineAPI* sEngineAPI = nullptr;

#if EDITOR
/**
 * @brief Adds items to the "3D" category of the Add Node menu.
 * @param parentNode The node to parent the new node under (may be null).
 * @param userData User data (unused).
 */
static void DrawCustom3dNodes(void* parentNode, void* userData)
{
    if (ImGui::MenuItem("Waypoint3D"))
    {
        sEngineAPI->LogDebug("Spawning Waypoint3D node");
    }

    if (ImGui::MenuItem("TriggerVolume3D"))
    {
        sEngineAPI->LogDebug("Spawning TriggerVolume3D node");
    }
}

/**
 * @brief Creates a new "AI" category in the Add Node menu.
 * @param parentNode The node to parent the new node under (may be null).
 * @param userData User data (unused).
 */
static void DrawAINodes(void* parentNode, void* userData)
{
    if (ImGui::MenuItem("NavMeshAgent"))
    {
        sEngineAPI->LogDebug("Spawning NavMeshAgent node");
    }

    if (ImGui::MenuItem("AIController"))
    {
        sEngineAPI->LogDebug("Spawning AIController node");
    }

    if (ImGui::MenuItem("BehaviorTree"))
    {
        sEngineAPI->LogDebug("Spawning BehaviorTree node");
    }
}

/**
 * @brief Adds items to the "Create Asset" submenu in the asset browser.
 * @param parentNode Unused for asset creation.
 * @param userData User data (unused).
 */
static void DrawCustomAssetTypes(void* parentNode, void* userData)
{
    if (ImGui::MenuItem("AI Behavior"))
    {
        sEngineAPI->LogDebug("Creating AI Behavior asset...");
    }

    if (ImGui::MenuItem("Dialogue Tree"))
    {
        sEngineAPI->LogDebug("Creating Dialogue Tree asset...");
    }
}
#endif

static int OnLoad(PolyphaseEngineAPI* api)
{
    sEngineAPI = api;
    return 0;
}

static void OnUnload()
{
    sEngineAPI = nullptr;
}

#if EDITOR
static void RegisterEditorUI(EditorUIHooks* hooks, uint64_t hookId)
{
    // Add items to existing "3D" category
    hooks->AddNodeMenuItems(hookId, "3D", DrawCustom3dNodes, nullptr);

    // Create a new "AI" category submenu
    hooks->AddNodeMenuItems(hookId, "AI", DrawAINodes, nullptr);

    // Extend the Create Asset submenu
    hooks->AddCreateAssetItems(hookId, DrawCustomAssetTypes, nullptr);
}
#endif

extern "C" OCTAVE_PLUGIN_API int PolyphasePlugin_GetDesc(PolyphasePluginDesc* desc)
{
    desc->apiVersion = OCTAVE_PLUGIN_API_VERSION;
    desc->pluginName = "Custom Node Types Addon";
    desc->pluginVersion = "1.0.0";
    desc->OnLoad = OnLoad;
    desc->OnUnload = OnUnload;
    desc->Tick = nullptr;
    desc->TickEditor = nullptr;
    desc->RegisterTypes = nullptr;
    desc->RegisterScriptFuncs = nullptr;
#if EDITOR
    desc->RegisterEditorUI = RegisterEditorUI;
#else
    desc->RegisterEditorUI = nullptr;
#endif
    desc->OnEditorPreInit = nullptr;
    desc->OnEditorReady = nullptr;
    return 0;
}

Result

The Add Node menu will look like:

Node
3D >
    (built-in 3D nodes)
    Waypoint3D          <-- addon item
    TriggerVolume3D     <-- addon item
Widget >
    (built-in widgets)
AI >                    <-- new custom category
    NavMeshAgent
    AIController
    BehaviorTree
Other >
    (built-in other nodes)

The Create Asset submenu will have:

Create Asset >
    (built-in asset types)
    AI Behavior         <-- addon item
    Dialogue Tree       <-- addon item

API Reference

AddNodeMenuItems

void (*AddNodeMenuItems)(HookId hookId, const char* category,
    MenuSectionDrawCallback drawFunc, void* userData);

Parameters: - hookId - The hook identifier - category - Category name: "3D", "Widget", "Other", or any custom name for a new submenu - drawFunc - Callback: void drawFunc(void* parentNode, void* userData) - userData - Optional user data

AddCreateAssetItems

void (*AddCreateAssetItems)(HookId hookId, MenuSectionDrawCallback drawFunc, void* userData);

Parameters: - hookId - The hook identifier - drawFunc - Callback: void drawFunc(void* parentNode, void* userData) - userData - Optional user data

AddSpawnBasic3dItems / AddSpawnBasicWidgetItems

void (*AddSpawnBasic3dItems)(HookId hookId, MenuSectionDrawCallback drawFunc, void* userData);
void (*AddSpawnBasicWidgetItems)(HookId hookId, MenuSectionDrawCallback drawFunc, void* userData);

Extends the Spawn Basic 3D/Widget menus (Shift+Q/Shift+W hotkey menus).

Best Practices

1. Built-in Categories - Use "3D", "Widget", or "Other" to add items to existing submenus
2. Custom Categories - Use any other string to create a new submenu section
3. Parent Node - The parentNode parameter is the node the user right-clicked on; use it to parent new nodes
4. Node Spawning - In a real addon, call the engine API to spawn nodes instead of just logging