Movement

Описание	Как управлять движением агентов на экране
Область знаний	Информатика, Game design, Геометрия
Область использования (ISTE)
Возрастная категория	10
Поясняющее видео
Близкие рецепту понятия
Среды и средства для приготовления рецепта:	Scratch, Snap!, NetLogo

Movement is the action of changing an object's position. It is used to show action. Scratch provides various blocks that can be used to create movement, including the Change X by (), Change Y by (), and Move () Steps blocks.

Following the Mouse

This script can be used to make a sprite follow the mouse-pointer.

when gf clicked // starts the script
forever // makes it so the movement will keep going
point towards (mouse-pointer v) // aims for the mouse
move (10) steps // moves

Arrow Keys Movement

This script gives more control over the movement, and it uses the arrow keys rather than the mouse. However, this script only allows for movement horizontally and vertically.

when green flag clicked // Starts the script.
forever // lets the script repeat
if <key (up arrow v) pressed?> then // if key is pressed
repeat until <not <key (up arrow v) pressed?>> // repeats until key is not pressed
change y by (10) // moves in wanted direction
end
end
if <key (down arrow v) pressed?> then
repeat until <not <key (down arrow v) pressed?>>
change y by (-10)
end
end
if <key (right arrow v) pressed?> then
repeat until <not <key (right arrow v) pressed?>>
change x by (10)
end
end
if <key (left arrow v) pressed?> then
repeat until <not <key (left arrow v) pressed?>>
change x by (-10)

This script is similar to the previous, but it allows diagonal movement as well. It works since the forever loop detects all keys and is not looping each individual key press.

when green flag clicked // starts the script
forever // lets the script repeat
if <key (up arrow v) pressed?> then // if key is pressed
change y by (10) // moves in wanted direction
end
if <key (down arrow v) pressed?> then
change y by (-10)
end
if <key (right arrow v) pressed?> then
change x by (10)
end
if <key (left arrow v) pressed?> then
change x by (-10)
end
end

Velocity Movement

This script creates a smoother form of movement. It works by gradually increasing or decreasing the amount that the sprite moves each loop through the use of a variable.

when gf clicked // starts the script
forever // loops the movement script
if <key (right arrow v) pressed> then // detects an input
change [x velocity v] by (1) // changes the velocity variable
end
if <key (left arrow v) pressed> then
change [x velocity v] by (-1)
end
set [x velocity v] to ((x velocity) * (0.9)) // slowly decreases velocity
change x by (x velocity) // makes the sprite move based on the velocity variable

See Also

• Jumping