Tweeny 2.0.1

Tweening animation engine for GameMaker LTS 2026

Tweeny is a tweening engine made for GameMaker, featuring a fluent chainable API, fire-and-forget use, more than 50 easing modes, sequential and parallel step execution, and flexible interpolation for variables, colors, angles, strings, and custom methods.

1. Create a tween instance and chain steps together:

   // Create a new tween
   t = new Tweeny();
   
   // Animate a variable over 2 seconds
   t.Variable(id, "x", 300, 2);

2. Use the fluent API to configure steps inline:

   // Chain multiple steps with easing
   t.Variable(id, "x", 300, 1).SetEaseCurve(TWEENY_EASE_BOUNCE, TWEENY_CHANNEL_OUT);
   t.Variable(id, "y", 400, 1).SetEaseCurve(TWEENY_EASE_ELASTIC, TWEENY_CHANNEL_OUT);

3. Run steps in parallel for simultaneous animations:

   // Move X and Y at the same time
   t.ParallelBegin();
   t.Variable(id, "x", 300, 1);
   t.Variable(id, "y", 400, 1);
   t.ParallelEnd();

4. Set loops, callbacks, and control playback:

   t.Variable(id, "x", 300, 1)
   t.Variable(id, "x", 100, 1)
   t.SetLoops(3).OnFinished(function() {
      show_debug_message("Animation complete!");
   })
   
   // Control playback
   t.Pause();
   t.Play();
   t.Skip();  // Jump to end

12 easing curves are available via macros, each with In, Out, InOut, and OutIn channels:

// Set easing on the whole tween
t.SetEaseCurve(TWEENY_EASE_BOUNCE, TWEENY_CHANNEL_OUT)
t.Variable(id, "x", 500, 1)

// Or per-step
t.Variable(id, "x", 500, 1).SetEaseCurve(TWEENY_EASE_ELASTIC, TWEENY_CHANNEL_IN)

Color and angle tweens handle their types automatically:

// Fade a color
t.Color(id, "colour", c_red, 1);

// Rotate with shortest angle path
t.Angle(id, "image_angle", 720, 2);

Animate strings by interpolating character ordinals:

t.String(id, "caption", "HELLO WORLD", 1);

Animate arbitrary values through a callback function:

t.Method(function(value) {
    audio_set_gain(snd_music, value, 0);
}, 0, 1, 2).SetEaseCurve(TWEENY_EASE_SINE, TWEENY_CHANNEL_IN);

Target values relative to the current value:

t.Variable(id, "x", 200, 1).Relative();

Override the starting value of a step:

t.Variable(id, "x", 500, 1).From(0);

Add delays between steps or wait without animation:

t.Variable(id, "x", 300, 2);
t.Interval(1); // Wait 1 second
t.Variable(id, "y", 400, 2);

Loop animations a finite number of times or infinitely:

// Infinite loop
t.Variable(id, "x", 500, 1);
t.Variable(id, "x", 100, 1);
t.SetLoops();

// Loop 5 times
t.SetLoops(5);

// Listen for loop completions
t.OnLoopFinished(function() {
    show_debug_message("Loop finished!");
});

Provide your own lerp function for a step:

t.Variable(id, "x", 500, 1).SetInterpolate(customLerp);

Manage all tweens at once:

TweenyPauseAll();
TweenyResumeAll();
TweenyStopAll();
TweenyFinishAll();

// Get all active tweens
var all = TweenyGetAll();

Sets the global timescale used by every tween:

TweenySetTimescale(1.0);

Creates a new tween chain. Optional source instance - the tween auto-destructs if the source is destroyed. Leave undefined if the tween is inside a struct or script

• Variable(instance, variable, target, duration) - Animate any numeric variable
• Color(instance, variable, target, duration) - Animate a colour variable
• Angle(instance, variable, target, duration) - Animate an angle (shortest path)
• String(instance, variable, target, duration) - Animate a string variable
• Method(func, from, to, duration) - Animate via custom callback (receives interpolated value)
• Interval(duration) - Wait/pause for a duration
• Callback(func, [args]) - Execute a function mid-sequence
• Await(func, [args]) - Awaits for a true return from the signal function

• SetEaseCurve(animCurve, [channel]) - Set per-step easing curve
• SetEaseFunc(easeFunc) - Set per-step easing function
• SetDelay(value) - Delay before the step executes (in frames)
• SetInterpolate(func) - Custom interpolation function (val1, val2, amount)
• Relative() - Make the target value relative to current
• From(value) - Override the starting value
• FromCurrent() - Explicitly snap the from value to the current value

• ParallelBegin() - Start parallel step group
• ParallelEnd() - End parallel step group

• SetSpeed(scale) - Set playback speed multiplier
• SetLoops([loops]) - Set loop count (0 = infinite, 1 = default)
• SetEase(animCurve, [channel]) - Set global easing for all steps
• Skip() - Jump to the end immediately
• Pause() - Pause the tween
• Play() - Resume the tween
• Stop() - Pause and reset to beginning
• Finish() - Finishes the tween
• Execute() - Start the tween

• IsRunning() - Check if the tween is actively playing
• IsPaused() - Check if the tween is paused
• IsValid() - Check if the tween is valid
• GetLoops() - Get total loop count
• GetLoopsLeft() - Get remaining loops
• GetElapsedTime() - Get elapsed time

• OnFinished(callback) - Called when all steps and loops finish
• OnLoopFinished(callback) - Called at the end of each loop
• OnStepFinished(callback) - Called when an individual step completes

• TweenySetTimescale(dt) - Override the global timescale
• TweenyPauseAll() - Pause all active tweens
• TweenyResumeAll() - Resume all paused tweens
• TweenyStopAll() - Stop all tweens
• TweenyFinishAll() - Finishes all the tweens
• TweenyDestroyAll() - Destroy all the tweens
• TweenyGetAll() - Get an array of all active tweens

• TWEENY_EASE_STEP, TWEENY_EASE_LINEAR, TWEENY_EASE_SINE, TWEENY_EASE_QUAD, TWEENY_EASE_CUBIC, TWEENY_EASE_QUART, TWEENY_EASE_QUINT, TWEENY_EASE_EXPO, TWEENY_EASE_CIRC, TWEENY_EASE_BACK, TWEENY_EASE_BOUNCE, TWEENY_EASE_ELASTIC, TWEENY_EASE_SPRING

• TWEENY_CHANNEL_IN, TWEENY_CHANNEL_OUT, TWEENY_CHANNEL_IN_OUT, TWEENY_CHANNEL_OUT_IN