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A driving engine is used in a variety of racing games, and can be very easy to replicate. There are two main ways that top-down driving works- in a non-scrollable world and a scrollable world. For the non-scrollable driving engine, only 1 script is needed.

Non-scrollable Engine

when gf clicked
go to x: (0) y: (0) // reset position
point in direction (90) // reset direction
set [turn v] to (0) // reset on flag click
set [velocity v] to (0) // reset on flag click
forever
if <(0) < (velocity)> then // if sprite moving forward
if <key [left arrow v] pressed?> then
change [turn v] by (-0.75) // affect direction negatively
change [velocity v] by (-0.15) // slow down forward movement on turn
end
if <key [right arrow v] pressed?> then
change [turn v] by (.75) // affect direction positively
change [velocity v] by (-0.15) // slow down forward movement on turn
end
else// if movement speed negative
if <key [left arrow v] pressed?> then
change [turn v] by (.75) // turn opposite direction, as with real cars
change [velocity v] by (.15) // slow down backward movement on turn
end
if <key [right arrow v] pressed?> then
change [turn v] by (-0.75) // turn opposite direction, as with real cars
change [velocity v] by (.15) // slow down backward movement on turn
end
end
if <key [up arrow v] pressed?> then
change [velocity v] by (.5) // move forward
end
if <key [down arrow v] pressed?> then
change [velocity v] by (-0.5) // move backward
end
set [turn v] to  ((turn) * (.9)) // gradually slow down, as in real physics
turn right (turn) degrees // set turn to control the sprite's direction
set [velocity v] to  ((velocity) * (.9)) // gradually slow down, as in real physics
move (velocity) steps // set velocity to control the sprite's position
end

Scrollable Engine

The main difference between the scrollable driving engine and the non-scrollable driving engine is that a non-scrollable driving engine is good for one computer, two player games, while a scrollable engine is primarily used in one player or online, cloud-based games.The scrollable driving engine requires two sprites- car and road- and as such, two separate scripts. The first one is very similar to the non-scrollable script.

when gf clicked
go to x: (0) y: (0) // reset position
point in direction (90) // reset direction
set [turn v] to (0) // reset on flag click
set [velocity v] to (0) // reset on flag click
forever
if <(0) < (velocity)> then // if sprite moving forward
if <key [left arrow v] pressed?> then
change [turn v] by (.75) // affect direction positively
change [velocity v] by (-0.15) // slow down forward movement on turn
end
if <key [right arrow v] pressed?> then
change [turn v] by (-0.75) // affect direction negatively
change [velocity v] by (-0.15) // slow down forward movement on turn
end
else// if movement speed negative
if <key [left arrow v] pressed?> then
change [turn v] by (-0.75) // turn opposite direction, as with real cars
change [velocity v] by (.15) // slow down backward movement on turn
end
if <key [right arrow v] pressed?> then
change [turn v] by (.75) // turn opposite direction, as with real cars
change [velocity v] by (.15) // slow down backward movement on turn
end
end
if <key [up arrow v] pressed?> then
change [velocity v] by (.5) // move forward
end
if <key [down arrow v] pressed?> then
change [velocity v] by (-0.5) // move backward
end
set [turn v] to  ((turn) * (.9)) // gradually slow down, as in real physics
set [velocity v] to  ((velocity) * (.9)) // gradually slow down, as in real physics
move (velocity) steps // set velocity to control the sprite's position
end

Here is the script that controls the movement of the 'road' the car is driving on.

Note Note: Remember that it must be a sprite, not a backdrop.
when gf clicked
set rotation style [don't rotate v]
go to x: (0) y: (0) // reset position
forever
move ((0) - (velocity)) steps// move opposite direction of velocity
point in direction ([direction v] of [car v]) // point in direction of car
end

See Also

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