In GameMaker Language (GML), changing the alpha of an object can be a useful technique for creating various visual effects in your game. Whether you want to make an object transparent, fade it in or out, or create a ghosting effect, adjusting its alpha value can help you achieve the desired visual impact. Here's how you can change the alpha of an object using GML.

1. Access the object's alpha value:

To change the alpha of an object, you need to access its alpha value. You can do this by referencing the object's alpha variable in GML. For example, if you want to change the alpha of an instance of the object named obj_sprite, you can use the following code:

obj_sprite.image_alpha = 0.5;

This line of code sets the alpha of the obj_sprite instance to 0.5, making it 50% opaque. You can adjust the value from 0 (fully transparent) to 1 (fully opaque) to achieve the desired transparency level.

2. Create a gradual alpha change:

If you want to create a gradual change in the alpha value of an object, you can use GML's built-in functions to interpolate the alpha over time. For example, you can use the lerp function to smoothly transition the alpha from its current value to a new value.

For instance, the following code can be used to gradually fade out the obj_sprite instance over a period of time:

var target_alpha = 0;

obj_sprite.image_alpha = lerp(obj_sprite.image_alpha, target_alpha, 0.05);

In this example, the lerp function is used to smoothly transition the obj_sprite's alpha towards the target_alpha value over time, creating a gradual fade-out effect.

3. Utilize alpha for visual effects:

Finally, changing the alpha of an object can be combined with other visual effects to create more complex and dynamic visuals in your game. For instance, you can use alpha adjustments to create a pulsating effect, simulate lighting changes, or dynamically highlight objects.

By controlling the alpha of objects in your game, you can add depth and visual interest to your game's graphics, enhancing the overall player experience.

In conclusion, using GML to change the alpha of an object allows you to create a wide range of visual effects in your game. Whether you want to adjust transparency, create gradual fades, or experiment with dynamic visual effects, mastering the manipulation of alpha values in GML can bring your game visuals to the next level.