frame-delta

Utility for counting frame time and frames per interval.

Usage

Install

npm install frame-delta --save

Code

var FrameDelta = require("FrameDelta").FrameDelta;
var sleep = require("sleep-promise");

// Create a new `FrameDelta` instance and tell it that we are aiming for
// 30 FPS. The `1000` (given to the constructor in the line below) is the
// interval (in milliseconds) that we want the `FrameDelta` to update its
// FPI.
var frames = new FrameDelta(1000);
frames.targetFPI = 30;

// Enter a render/update loop.
while (windowIsOpen) {
    render();
    update();

    // We can get the frames per interval (FPI) and frame time from the
    // instance. These values will be `0` the first time we print them, as
    // it takes at least one render/update loop iteration before these values
    // can be determined.
    console.log("FPS: " + frames.fpi);
    console.log("Frame Time: " + frames.frameTime);

    // Based on the current frame time (duration between last two frame
    // updates), the `FrameDelta` instance will suggest the optimal amount
    // of time we can suspend the thread so we don't hammer the CPU, whilst
    // still allowing us to get our target FPI.
    await sleep(frames.loopSleepTime);

    // Tell the instance that the frame is over.
    this.frames.nextFrame();
}

Build

frame-delta is built using gulp. You can invoke the build process by using either gulp directly, or via an npm script which calls gulp. (Basically, both the npm script and the gulp command do exactly the same thing.)

    npm run build
    // Or
    gulp build

License

See the LICENSE file for license information.