image_speed

From YoYoGames Wiki

Description

(real): the speed at which a subimage of an object's sprite will progress

• Read-write
• Scope: Local

Explanation

The image_index local variable is the variable that defines the speed that the sub-image of an object's sprite progresses. Each sprite could have an number of images greater than 1, and the object 'animates' by moving a ceratin number of images per step.

Definition

Strictly speaking its "definition", image_speed is the number added to the current image index on each step. But this does not explain what does it do.

What does it do

Game Maker automatically increments the value image_index (and image_single in pre-6.x versions, but with conditions) of image_speed itself, then wraps the value around the maximum number of images, so if a sprite has 30 images, and the number 34 is reached, it is automatically turned into 4.

Remarks

Conditions of incrementing image_single in pre-6.0 versions

The image_single variable is incrmented then wrapped around the maximum number of existing images in the sprite, however, unlike image_index, when image_single is equal to -1, it is not incremented at all.