Top-Down Racing Game

In this lesson, you will create a top-down racing game in GameMaker. Instead of the car immediately moving at full speed, it will gradually accelerate, slow down using friction, and steer around a race track.

Lesson Objectives

By the end of this lesson, you should be able to:

• Create a car that gradually accelerates.
• Create braking and reverse movement.
• Steer the car left and right.
• Add friction.
• Limit the maximum speed.
• Create a race track.
• Create checkpoints.
• Require checkpoints to be completed in order.
• Count completed laps.

Game Requirements

Part 1 - Create the Project

Create a new GameMaker project named:

PX_lastname_Top-DownRacing

Create the following assets:

spr_car
obj_car

spr_checkpoint
obj_checkpoint

spr_wall
obj_wall

rm_race

Part 2 - Create the Car

Create a sprite named:

spr_car

The car should be viewed from above. A simple rectangle is fine.

Set the sprite origin to:

Middle Center

Create an object named:

obj_car

Assign spr_car to the object.

Part 3 - Create the Car Variables

Add a Create Event to obj_car.

car_speed = 0;

acceleration = 0.15;
brake_power = 0.20;

max_speed = 6;
max_reverse = -2;

friction = 0.05;

turn_speed = 3;

next_checkpoint = 0;
lap = 0;

What Do These Variables Mean?

Part 4 - Add Acceleration

Add a Step Event to obj_car.

if (keyboard_check(vk_up))
{
    car_speed += acceleration;
}

Holding the Up Arrow gradually increases the car's speed.

Part 5 - Add Braking and Reverse

if (keyboard_check(vk_down))
{
    car_speed -= brake_power;
}

The Down Arrow slows the car. If the player continues holding Down, the car can move backward.

Part 6 - Limit the Speed

car_speed = clamp(car_speed, max_reverse, max_speed);

The clamp() function keeps a value between a minimum and maximum.

Minimum = -2
Maximum = 6

Part 7 - Add Friction

if (!keyboard_check(vk_up) && !keyboard_check(vk_down))
{
    if (car_speed > 0)
    {
        car_speed -= friction;
        car_speed = max(car_speed, 0);
    }

    if (car_speed < 0)
    {
        car_speed += friction;
        car_speed = min(car_speed, 0);
    }
}

Release the accelerator. The car should gradually slow down instead of stopping instantly.

Part 8 - Add Steering

if (abs(car_speed) > 0.1)
{
    if (keyboard_check(vk_left))
    {
        image_angle += turn_speed;
    }

    if (keyboard_check(vk_right))
    {
        image_angle -= turn_speed;
    }
}

The car can turn only when it is moving. This makes the controls feel more like a real vehicle.

Part 9 - Move the Car

x += lengthdir_x(car_speed, image_angle);
y += lengthdir_y(car_speed, image_angle);

These functions use the direction of the car to calculate horizontal and vertical movement.

Complete Step Event

// ACCELERATE

if (keyboard_check(vk_up))
{
    car_speed += acceleration;
}


// BRAKE / REVERSE

if (keyboard_check(vk_down))
{
    car_speed -= brake_power;
}


// LIMIT SPEED

car_speed = clamp(car_speed, max_reverse, max_speed);


// FRICTION

if (!keyboard_check(vk_up) && !keyboard_check(vk_down))
{
    if (car_speed > 0)
    {
        car_speed -= friction;
        car_speed = max(car_speed, 0);
    }

    if (car_speed < 0)
    {
        car_speed += friction;
        car_speed = min(car_speed, 0);
    }
}


// STEERING

if (abs(car_speed) > 0.1)
{
    if (keyboard_check(vk_left))
    {
        image_angle += turn_speed;
    }

    if (keyboard_check(vk_right))
    {
        image_angle -= turn_speed;
    }
}


// MOVE

x += lengthdir_x(car_speed, image_angle);
y += lengthdir_y(car_speed, image_angle);

Part 10 - Test the Car

Place obj_car inside:

rm_race

Run the game and test the controls.

Part 11 - Create the Race Track

Create your race track inside rm_race.

You can use:

• Road sprites
• Grass
• Barriers
• Walls
• Cones
• Simple colored shapes

The track should form a complete circuit.

        +-----------------------+
        |                       |
        |     +-----------+     |
        |     |           |     |
        |     |           |     |
        |     +-----------+     |
        |                       |
        +-----------------------+

Part 12 - Create Checkpoints

Create:

spr_checkpoint

A checkpoint can be a rectangle placed across the road.

Create:

obj_checkpoint

Add a Create Event:

checkpoint_number = 0;

Each checkpoint should have a different number.

Checkpoint 0
Checkpoint 1
Checkpoint 2
Checkpoint 3

Part 13 - Number the Checkpoints

Starting Line = 0

Checkpoint 1 = 1

Checkpoint 2 = 2

Checkpoint 3 = 3

The player should drive through them in this order:

0 -> 1 -> 2 -> 3 -> 0

Part 14 - Detect Checkpoints

In obj_car, add a Collision Event with obj_checkpoint.

if (other.checkpoint_number == next_checkpoint)
{
    next_checkpoint += 1;
}

The car only accepts the correct checkpoint.

Part 15 - Complete a Lap

If you have four checkpoints numbered 0 through 3, use:

if (other.checkpoint_number == next_checkpoint)
{
    next_checkpoint += 1;

    if (next_checkpoint >= 4)
    {
        next_checkpoint = 0;
        lap += 1;
    }
}

When the player reaches all four checkpoints, the lap counter increases.

Part 16 - Display Race Information

Add a Draw GUI Event to obj_car.

draw_text(20, 20, "Lap: " + string(lap));
draw_text(20, 50, "Next Checkpoint: " + string(next_checkpoint));
draw_text(20, 80, "Speed: " + string(round(car_speed)));

Your game should display information similar to:

Lap: 2
Next Checkpoint: 3
Speed: 5

Challenge 1 - Better Steering

var steering_amount = turn_speed * abs(car_speed / max_speed);

if (keyboard_check(vk_left))
{
    image_angle += steering_amount;
}

if (keyboard_check(vk_right))
{
    image_angle -= steering_amount;
}

Challenge 2 - Wall Collisions

obj_wall

car_speed *= -0.3;

Challenge 3 - Off-Road Penalty

car_speed *= 0.95;

Challenge 4 - Add a Timer

race_time = 0;

race_time += 1 / room_speed;

draw_text(20, 110,
    "Time: " + string_format(race_time, 0, 2));

Challenge 5 - Three-Lap Race

total_laps = 3;

if (lap >= total_laps)

RACE COMPLETE!

Final Game Checklist

• ☐ A top-down car
• ☐ Up Arrow acceleration
• ☐ Down Arrow braking/reverse
• ☐ Left and Right steering
• ☐ Gradual acceleration
• ☐ Friction
• ☐ Maximum speed
• ☐ Race track
• ☐ At least four checkpoints
• ☐ Checkpoints completed in order
• ☐ Lap counter
• ☐ Speed displayed on screen
• ☐ Game runs without errors

Student Reflection

1. What variable controls how quickly the car accelerates?
2. What is the purpose of friction?
3. Why do we use clamp()?
4. Why should checkpoints have numbers?
5. What would happen if the player could cross checkpoints in any order?
6. What change did you make that improved your game the most?

Extension Goal

After completing the basic game, try adding one or more advanced features:

• Computer-controlled racers
• Best lap times
• 3-2-1-GO countdown
• Engine sound effects
• Drifting
• Boost pads
• Multiple race tracks
• Car selection
• High-score system