add global variable F to count frames

Author: luizbills

src/index.js

@@ -105,6 +105,9 @@ export default function litecanvas(settings = {}) {
         /** @type {number} */
         T: 0,
 
+        /** @type {number} */
+        F: 0,
+
         /** @type {number} */
         MX: -1,
 
@@ -1622,6 +1625,7 @@ export default function litecanvas(settings = {}) {
 
         if (updated) {
             instance.emit('draw', _ctx)
+            instance.def('F', instance.F + 1)
             if (updated > 1) {
                 _accumulated = 0
                 DEV: console.warn(

tests/globals.js

@@ -0,0 +1,29 @@
+import test from 'ava'
+import litecanvas from '../src/index.js'
+import * as sinon from 'sinon'
+
+test.before(() => {
+    sinon.stub(console) // silent console
+})
+
+test('variable F should count frames', async (t) => {
+    t.plan(1)
+
+    const local = litecanvas({
+        global: false,
+    })
+    const expected = 3
+
+    await new Promise((resolve) => {
+        let i = expected
+        local.listen('draw', () => {
+            i--
+            if (i === 0) {
+                resolve()
+                local.quit()
+            }
+        })
+    })
+
+    t.is(local.F, expected)
+})

types/global.d.ts

@@ -11,6 +11,8 @@ declare global {
     var H: number
     /** the amount of time (in seconds) since the game started */
     var T: number
+    /** the amount of rendered frames */
+    var F: number
     /** The current mouse's horizontal (X) position or -1 (if the mouse was not used or detected) */
     var MX: number
     /** The current mouse's vertical (Y) position or -1 (if the mouse was not used or detected) */

types/types.d.ts

@@ -5,6 +5,8 @@ type LitecanvasInstance = {
     H: number
     /** the amount of time (in seconds) since the game started */
     T: number
+    /** the amount of rendered frames */
+    F: number
     /** The current mouse's horizontal (X) position or -1 (if the mouse was not used or detected) */
     MX: number
     /** The current mouse's vertical (Y) position or -1 (if the mouse was not used or detected) */