Tilt Controls in JavaScript Games [Understanding AI - Lesson 12 / 15]
TLDRThis video tutorial introduces viewers to the concept of using the device orientation sensor to create tilt controls for mobile games and applications. The host begins by expressing his initial fascination with mobile games that utilized phone tilting as a control mechanism. Despite losing interest in such games due to their basic nature compared to PC or console games, he delves into the technicalities of implementing tilt controls using JavaScript. The video demonstrates how to use HTML, CSS, and JavaScript to create a canvas element that visualizes phone sensor values. It guides viewers through styling the canvas, drawing an animated ellipse, and connecting the tilt sensor to the canvas for a dynamic user experience. The tutorial then shifts to creating a 'phone controls' JavaScript class that listens to device orientation changes and updates the game's steering accordingly. The host also discusses the use of the 'device motion' event for a smoother and more accurate control experience. Finally, the video integrates the tilt controls into a racing game, offering viewers a practical application of the concepts learned. The host encourages viewers to experiment with the code and adapt it to their needs, whether for gaming or other interactive applications.
Takeaways
- 🎮 **Mobile Gaming Tilt Controls**: The video introduces how to implement tilt controls in mobile games using the device orientation sensor for steering.
- 📱 **Device Orientation Sensor**: The device orientation sensor is used to detect the tilt of the phone, which can be applied to various apps beyond gaming.
- 📐 **Canvas Visualization**: A canvas element is used to visualize the phone's sensor values, with styling applied to make it more visually appealing.
- 🔵 **Styling the Canvas**: The canvas is styled with an orange background and positioned in the center of the screen with CSS.
- 📈 **Drawing on Canvas**: JavaScript is used to draw an ellipse on the canvas, which is later animated and used to represent the tilt visually.
- 🔄 **Animating the Ellipse**: An animation loop is created to continuously rotate the ellipse, simulating the tilt effect.
- 📱 **Phone Controls Implementation**: A separate JavaScript file implements phone controls that respond to the device's orientation changes.
- ↕️ **Tilt Measurement**: The beta value from the device orientation event is used to measure the tilt, with negative values indicating left tilt and positive indicating right.
- 🔀 **Smoothing the Tilt**: To smooth out the tilt effect, the canvas angle is updated as a weighted average of the current and new angles.
- 🛠️ **Integration with Racing Game**: The tilt controls are integrated into a racing game, where the car's steering is influenced by the phone's tilt.
- 📱 **Testing on Mobile**: The script is tested on an actual mobile device to ensure that the tilt controls function as intended.
Q & A
What was the initial reaction to mobile games with tilt controls?
-The initial reaction was amazement, as it was considered the coolest thing ever for steering games by tilting the phone.
Why did the speaker get bored of mobile games after playing for a short time?
-The speaker got bored because mobile games at the time were basic compared to PC or console games.
What is the purpose of using the device orientation sensor in games?
-The device orientation sensor is used to detect the tilt of the device, which can be used to control games and other applications.
How can the knowledge from this lesson be applied outside of gaming?
-The knowledge can be applied to create other apps, such as ones to measure the heights of trees or distances to far away objects.
What is the first step in creating a tilt-controlled game using HTML?
-The first step is to create an HTML file with basic syntax, including a canvas element for visualizing phone sensor values.
How is the canvas element styled to be in the center of the screen?
-The canvas is styled with a background color, positioned absolutely at 50% top and left, and then translated by half its width towards the left and top.
What is the purpose of drawing an ellipse in the middle of the canvas?
-The ellipse serves as a visual representation of the phone's tilt, which can be animated and rotated based on the device's orientation.
How is the rotation of the ellipse animated?
-An animation loop is created that increases the rotation on every frame and redraws the ellipse at the new rotation, calling requestAnimationFrame to repeat the process.
What is the role of the 'phoneControls' class in the script?
-The 'phoneControls' class is responsible for tracking the tilt of the phone using the device orientation sensor and updating the game or application accordingly.
How can the game be tested on a computer without a physical mobile device?
-Developer tools in browsers like Google Chrome can simulate device orientation, allowing for testing of tilt controls on a computer.
What is the final step in integrating tilt controls into a racing game?
-The final step is to update the game's control logic to respond to the tilt values from the 'phoneControls' class, allowing the player to steer the car by tilting the phone.
Outlines
📱 Introduction to Mobile Gaming and Device Orientation Sensor
The speaker begins by reminiscing about the initial excitement of mobile games that used the device orientation sensor for steering by tilting the phone. They express that while these games were basic compared to PC or console games, the concept was intriguing. The speaker then introduces the topic of the video: teaching viewers how to use the device orientation sensor to create games and other applications, such as measuring tree heights or distances to objects. They also mention a friend's game, 'Ja Man versus Metal Heads,' available on the Play Store, as an example of a non-racing game utilizing this technology.
🎨 Setting Up HTML and Canvas for Phone Tilt Experiment
The speaker guides viewers through setting up an HTML file named 'index.html' with basic syntax, including a 'head' section and a 'body' with a 'canvas' element for visualizing phone sensor values. They then demonstrate how to style the canvas with an orange background and center it on the screen, adjusting its position and size. The canvas is set to a width of 700 and a height of 500 pixels. JavaScript is introduced to draw an ellipse in the middle of the canvas, with a unique ID assigned for reference. The speaker explains how to access the canvas context and use the 'ellipse' method to draw the shape.
🔄 Animating the Ellipse and Connecting to Phone Sensors
The speaker continues by discussing the parameters of the 'ellipse' method in the canvas context, including the center coordinates, radii, rotation, and the extent of the ellipse. They animate the ellipse to rotate and explain how to create an animation loop using 'requestAnimationFrame' for a smooth effect. The animation is refined to clear the canvas on each frame to prevent a chaotic buildup of ellipses. The speaker then transitions to connecting the animation with the phone's device orientation sensor, introducing the concept of using the 'beta' angle for steering in a racing game.
📱 Implementing Phone Controls and Responding to Device Orientation
The speaker outlines the process of creating a 'phone-controls.js' file to handle the phone's tilt and rotation. They explain how to define a 'phoneControls' class, initialize tilt to zero, and add event listeners for the 'deviceorientation' event. The speaker demonstrates how to log sensor data and use the 'beta' angle to determine the steering direction. They also discuss simulating phone orientation using developer tools and the importance of using the 'gamma' value to keep the game content flat and oriented correctly during phone rotation.
🧭 Refining Tilt Measurements and Smoothing the Animation
The speaker refines the tilt measurement method by using the 'devicemotion' event instead of 'deviceorientation', which provides a more stable and less noisy signal. They explain the phone's coordinate system and how to calculate the angle of gravity on the X and Y axes to determine the tilt. The speaker introduces a method to reduce flickering by only updating the canvas angle when there's a significant change. They also suggest a smoothing technique by blending the new canvas angle with the previous one, resulting in a smoother animation.
🏎️ Integrating Phone Controls into a Racing Game
The speaker challenges viewers to implement forward and reverse controls for the racing game using the phone's tilt. They demonstrate a simple interface where touching the screen activates the brake, and the car moves forward by default. The speaker guides viewers on how to integrate the newly created phone controls into an existing racing game codebase, ensuring backward compatibility with keyboard controls. They also discuss the need to adjust the car's rotation angle based on the phone's tilt and provide a solution for a more efficient and smoother gaming experience on mobile devices.
📱 Testing and Optimizing the Racing Game for Mobile Devices
The speaker addresses the need to test the racing game on mobile devices and discusses the challenges of simulating touch events on a small screen. They suggest hiding certain UI elements for a cleaner interface and provide a solution to enable full-screen gameplay with sound activation on startup. The speaker also mentions plans to optimize the game for better performance and to host it on their website for easier access.
Mindmap
Keywords
💡Tilt Controls
💡Device Orientation Sensor
💡Mobile Games
💡Canvas Element
💡JavaScript
💡Racing Game
💡Beta Angle
💡Animation Loop
💡CSS Attributes
💡Device Motion Event
💡Arctan Function
Highlights
Introduction to using the device orientation sensor for phone tilt controls in mobile games.
Creating a basic HTML structure for the game with a canvas element for visualization.
Styling the canvas with an orange background and centering it on the screen.
Setting the canvas size and drawing an ellipse in the middle using JavaScript.
Animating the ellipse rotation and optimizing the animation loop for smoothness.
Clearing the canvas on each frame to prevent graphical artifacts.
Implementing phone controls to respond to the device's tilt using the beta angle from the device orientation event.
Simulating phone tilt using developer tools for testing on a computer.
Using the device motion event for a more accurate tilt measurement and creating a bubble level app.
Integrating phone tilt controls into a racing game for steering and movement.
Creating a simple interface for the racing game with touch controls for braking and acceleration.
Making the game backward compatible to support both keyboard and phone controls.
Optimizing the game for efficiency and full-screen mobile play.
Challenge for users to implement forward, reverse, and speed control using phone tilt.
Instructions on hiding certain UI elements for a cleaner mobile gameplay experience.
Testing the game on an actual mobile device for accurate tilt controls and performance.
Adjusting the car's rotation angle based on phone tilt for a more realistic driving experience.
Final touches on the game, including sound activation and fullscreen mode for an immersive experience.