Examples
Real, tested patterns extracted from PrismaInventory_F4 and PrismaShowcase_F4.
1. Minimal Toggle Menu
The simplest possible plugin: one view, one hotkey, show/hide with game pause.
C++ (main.cpp):
#include "PrismaUI_F4_API.h"
#include "KeyHandler.h"
#include <spdlog/sinks/basic_file_sink.h>
static PRISMA_UI_API::IVPrismaUI3* g_api = nullptr;
static PrismaView g_view = 0;
static bool g_visible = false;
static void OnDomReady(PrismaView view) {
g_api->RegisterJSListener(view, "requestClose", [](const char*) {
// No RE:: access — safe to call PrismaUI directly here
g_visible = false;
g_api->Unfocus(g_view);
g_api->Hide(g_view);
});
logger::info("DOM ready");
}
static void Toggle() {
if (!g_api || !g_api->IsValid(g_view)) return;
g_visible = !g_visible;
if (g_visible) {
g_api->Show(g_view);
g_api->Focus(g_view, true, false); // pauseGame=true
} else {
g_api->Unfocus(g_view);
g_api->Hide(g_view);
}
}
static void F4SEMessageHandler(F4SE::MessagingInterface::Message* msg) {
switch (msg->type) {
case F4SE::MessagingInterface::kGameDataReady:
g_api = PRISMA_UI_API::RequestPluginAPI<PRISMA_UI_API::IVPrismaUI3>();
KeyHandler::RegisterSink();
KeyHandler::GetSingleton()->Register(0x43, KeyEventType::KEY_DOWN, Toggle); // F9
break;
case F4SE::MessagingInterface::kPostLoadGame:
case F4SE::MessagingInterface::kNewGame:
if (g_api && g_view == 0) {
g_view = g_api->CreateView("mymenu.html", OnDomReady);
g_api->RegisterConsoleCallback(g_view,
[](PrismaView, PRISMA_UI_API::ConsoleMessageLevel lvl, const char* msg) {
logger::info("[JS] {}", msg);
});
g_api->RegisterTranslations(g_view, "MyPlugin_F4");
g_api->Hide(g_view);
}
break;
}
}HTML (mymenu.html):
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8">
<style>
* { margin:0; padding:0; box-sizing:border-box; }
body { width:100vw; height:100vh; background:transparent;
display:flex; align-items:center; justify-content:center;
font-family:'Courier New',monospace; }
.panel { background:rgba(0,0,0,0.9); border:1px solid #00661a;
padding:40px; color:#00ff41; text-align:center; }
button { margin-top:20px; padding:10px 24px; background:transparent;
border:1px solid #00661a; color:#00ff41; font-family:'Courier New',monospace;
font-size:12px; cursor:pointer; letter-spacing:2px; }
button:hover { background:rgba(0,255,65,0.1); }
</style>
</head>
<body>
<div class="panel">
<h2 style="letter-spacing:3px" id="title">MY MENU</h2>
<p style="margin-top:12px;color:#009921;font-size:11px">Game is paused.</p>
<button onclick="requestClose()">CLOSE</button>
</div>
<script>
console.log('mymenu ready');
// Use t() for localized strings if RegisterTranslations was called
// document.getElementById('title').textContent = t('ui.title');
</script>
</body>
</html>2. Pushing Structured Data to a View
Push game data to the HTML page using InteropCall with JSON. Always call this from the game thread (inside AddTask or an F4SE message handler).
C++ — build and push inventory:
#include <nlohmann/json.hpp> // or build JSON manually with sprintf
static void PushInventoryData(PrismaView view) {
// Must be called on game thread — RE:: access requires it
auto* player = RE::PlayerCharacter::GetSingleton();
if (!player) return;
std::string json = "[";
bool first = true;
player->GetInventory([&](RE::TESBoundObject& obj, const RE::InventoryEntryData& entry) {
if (!first) json += ",";
first = false;
json += "{\"name\":\"" + std::string(obj.GetFullName()) + "\""
+ ",\"count\":" + std::to_string(entry.countDelta)
+ ",\"weight\":" + std::to_string(obj.GetWeight())
+ "}";
});
json += "]";
g_api->InteropCall(view, "loadInventory", json.c_str());
}HTML — receive and render:
<div id="list"></div>
<script>
function loadInventory(jsonStr) {
var items = JSON.parse(jsonStr);
var html = '';
items.forEach(function(item) {
html += '<div class="row">'
+ '<span class="name">' + escapeHtml(item.name) + '</span>'
+ '<span class="count">x' + item.count + '</span>'
+ '</div>';
});
document.getElementById('list').innerHTML = html;
}
function escapeHtml(str) {
return str.replace(/&/g,'&').replace(/</g,'<').replace(/>/g,'>');
}
</script>3. Receiving Events from JavaScript
The JS → C++ direction uses RegisterJSListener. Callbacks fire on the Ultralight render thread — if you need RE:: access, dispatch via AddTask.
C++ — register multiple listeners:
static void OnDomReady(PrismaView view) {
// Safe: no RE:: access, just UI state
g_api->RegisterJSListener(view, "requestClose", [](const char*) {
g_api->Unfocus(g_view);
g_api->Hide(g_view);
g_visible = false;
});
// Safe: logging only — no RE::
g_api->RegisterJSListener(view, "onSettingChanged", [](const char* json) {
logger::info("Setting: {}", json);
// Parse and apply without RE::, or dispatch to game thread:
std::string j = json;
F4SE::GetTaskInterface()->AddTask([j]() {
// Apply setting via RE:: here if needed
});
});
// CORRECT: RE:: access dispatched to game thread
g_api->RegisterJSListener(view, "onItemSelected", [](const char* formIdStr) {
std::string s = formIdStr ? formIdStr : "";
F4SE::GetTaskInterface()->AddTask([s]() {
uint32_t formId = std::stoul(s, nullptr, 16);
auto* form = RE::TESForm::GetFormByID(formId);
if (form) logger::info("Selected: {}", form->GetFullName());
});
});
}HTML — call from buttons and inputs:
// Close
document.getElementById('closeBtn').onclick = function() {
requestClose();
};
// Setting slider
document.getElementById('hungerSlider').oninput = function() {
onSettingChanged(JSON.stringify({ key: 'hungerRate', value: this.value }));
};
// Item click
document.querySelectorAll('.item-row').forEach(function(el) {
el.onclick = function() {
onItemSelected(this.dataset.formid);
};
});4. Querying Game Data from a JS Listener
The full round-trip pattern: JS asks for data → C++ dispatches to game thread → reads RE:: → sends result back to JS.
// C++ — in OnDomReady
g_api->RegisterJSListener(view, "requestPlayerStats", [](const char* /*arg*/) {
// Ultralight thread — dispatch to game thread for RE:: access
F4SE::GetTaskInterface()->AddTask([]() {
auto* player = RE::PlayerCharacter::GetSingleton();
if (!player || !g_api || !g_api->IsValid(g_view)) return;
std::string json = "{"
"\"hp\":" + std::to_string((int)player->GetActorValue(RE::ActorValue::kHealth)) +
",\"ap\":" + std::to_string((int)player->GetActorValue(RE::ActorValue::kActionPoints)) +
",\"name\":\"" + std::string(player->GetFullName()) + "\""
"}";
g_api->InteropCall(g_view, "onPlayerStats", json.c_str());
});
});// JS — trigger from a button
document.getElementById('refreshBtn').onclick = function() {
requestPlayerStats(); // fires C++ listener
};
// JS — receive result
function onPlayerStats(json) {
var d = JSON.parse(json);
document.getElementById('hp').textContent = d.hp;
document.getElementById('ap').textContent = d.ap;
}5. Reading a Value Back from JS
Invoke with a callback lets you pull a value from the page’s JS state. The callback fires on the game thread.
// Ask the page what the current slider value is
g_api->Invoke(view,
"document.getElementById('volumeSlider').value",
[](const char* result) {
// Game thread — safe for RE:: access
int volume = std::atoi(result);
logger::info("Volume is {}", volume);
});For passing complex state back, have JS call a listener instead — it’s cleaner than parsing Invoke results.
6. Translations (V3)
RegisterTranslations injects window.t() and window.L10N into the page. Call it once after CreateView.
Translation file (Data\Interface\Translations\MyPlugin_F4_en.txt):
ui.title MY MENU
ui.close CLOSE
ui.hp Health
ui.ap Action PointsC++:
// kPostLoadGame / kNewGame
g_view = g_api->CreateView("mymenu.html", OnDomReady);
g_api->RegisterTranslations(g_view, "MyPlugin_F4"); // must match the filename prefixHTML:
<script>
// t() returns the translated string, or the key if not found
document.getElementById('title').textContent = t('ui.title');
document.getElementById('closeBtn').textContent = t('ui.close');
// L10N is the raw key→value map
console.log(L10N['ui.title']);
</script>Translations are re-injected automatically on each subsequent page load — call RegisterTranslations once per view.
7. Four Views, Four Keys (Showcase Pattern)
Managing multiple views from a single plugin. Each view is independent.
static constexpr uint32_t KEYS[4] = { 0x43, 0x44, 0x57, 0x58 }; // F9-F12
static constexpr const char* FILES[4] = { "levelup.html", "mcm.html",
"companion.html", "terminal.html" };
static PRISMA_UI_API::IVPrismaUI3* g_api = nullptr;
static PrismaView g_views[4] = {};
static bool g_visible[4] = {};
static void Toggle(int idx) {
if (!g_api || !g_api->IsValid(g_views[idx])) return;
g_visible[idx] = !g_visible[idx];
if (g_visible[idx]) {
g_api->Show(g_views[idx]);
g_api->Focus(g_views[idx], true, false);
} else {
g_api->Unfocus(g_views[idx]);
g_api->Hide(g_views[idx]);
}
}
static void CreateViews() {
for (int i = 0; i < 4; i++) {
if (g_views[i] != 0) continue;
g_views[i] = g_api->CreateView(FILES[i], nullptr);
g_api->RegisterConsoleCallback(g_views[i],
[](PrismaView, PRISMA_UI_API::ConsoleMessageLevel, const char* msg) {
logger::info("[JS] {}", msg);
});
g_api->RegisterTranslations(g_views[i], "MyPlugin_F4");
g_api->Hide(g_views[i]);
}
}
static void F4SEMessageHandler(F4SE::MessagingInterface::Message* msg) {
switch (msg->type) {
case F4SE::MessagingInterface::kGameDataReady:
g_api = PRISMA_UI_API::RequestPluginAPI<PRISMA_UI_API::IVPrismaUI3>();
KeyHandler::RegisterSink();
for (int i = 0; i < 4; i++) {
KeyHandler::GetSingleton()->Register(KEYS[i], KeyEventType::KEY_DOWN,
[i]() { Toggle(i); });
}
break;
case F4SE::MessagingInterface::kPostLoadGame:
case F4SE::MessagingInterface::kNewGame:
if (g_api) CreateViews();
break;
}
}8. Z-Ordering Two Overlapping Views
// Background HUD — always visible, no focus, low z-order
g_hudView = g_api->CreateView("hud.html", nullptr);
g_api->SetOrder(g_hudView, 0);
g_api->Show(g_hudView); // visible but unfocused
// Popup menu — appears on top of HUD when opened
g_menuView = g_api->CreateView("menu.html", OnMenuReady);
g_api->SetOrder(g_menuView, 10);
g_api->Hide(g_menuView);The HUD renders continuously. When the menu is opened with Show + Focus, it renders over the HUD because its order value (10) is higher.
9. Updating a HUD Each Second
For a heads-up display that shows live stats, push updates from a recurring game-thread task. All RE:: access is safe inside AddTask.
static void ScheduleHudUpdate() {
F4SE::GetTaskInterface()->AddTask([]() {
if (!g_api || !g_api->IsValid(g_hudView) || g_api->IsHidden(g_hudView)) {
ScheduleHudUpdate();
return;
}
auto* player = RE::PlayerCharacter::GetSingleton();
if (!player) { ScheduleHudUpdate(); return; }
std::string json = "{\"hp\":" + std::to_string((int)player->GetActorValue(RE::ActorValue::kHealth))
+ ",\"ap\":" + std::to_string((int)player->GetActorValue(RE::ActorValue::kActionPoints))
+ "}";
g_api->InteropCall(g_hudView, "updateStats", json.c_str());
ScheduleHudUpdate(); // re-schedule
});
}For a real HUD, hook the game’s tick or use a 1-second timer rather than a tight recursion loop. The example above shows the pattern; adjust the scheduling mechanism to your needs.
10. Inspector Setup (Development Only)
#ifdef PRISMA_DEV
static void SetupInspector(PrismaView view) {
g_api->CreateInspectorView(view);
// Position inspector on right half of a 1920-wide screen
g_api->SetInspectorBounds(view, 960.0f, 0.0f, 960, 600);
g_api->SetInspectorVisibility(view, true);
}
// Bind F12 to toggle inspector during dev
KeyHandler::GetSingleton()->Register(0x58, KeyEventType::KEY_DOWN, []() {
bool v = g_api->IsInspectorVisible(g_view);
g_api->SetInspectorVisibility(g_view, !v);
});
#endifRemove all CreateInspectorView calls before releasing your mod.
11. Error-Resilient View Creation
static void CreateViews() {
if (!g_api) {
logger::error("PrismaUI not available — is PrismaUI_F4.dll installed and loaded?");
return;
}
if (g_view != 0) return; // already created
g_view = g_api->CreateView("mymenu.html", OnDomReady);
if (!g_api->IsValid(g_view)) {
logger::error("Created view is immediately invalid — check that mymenu.html exists in Data/PrismaUI_F4/views/");
g_view = 0;
return;
}
g_api->RegisterConsoleCallback(g_view,
[](PrismaView, PRISMA_UI_API::ConsoleMessageLevel lvl, const char* msg) {
if (lvl == PRISMA_UI_API::ConsoleMessageLevel::Error)
logger::error("[JS ERR] {}", msg);
else
logger::info("[JS] {}", msg);
});
g_api->RegisterTranslations(g_view, "MyPlugin_F4");
g_api->Hide(g_view);
logger::info("View created (id={})", g_view);
}The most common failure modes:
g_apiis null → PrismaUI_F4 is not installed or failed to load, orRequestPluginAPIwas called beforekGameDataReadyIsValidreturns false immediately → the HTML file path is wrong- JS errors in console → check HTML/JS syntax errors, missing function guards
- Game data listeners return no data → JS listener accessed
RE::directly instead of dispatching viaAddTask