Speedometer

Solutions for those exercises are behind the speedometer feature.

Displaying the Speedometer

Display the speedometer images, with the images available in the assets/speedometer folder.

Tips:

• The hand will need a position relative to the dial
  • It will need to rotate around the center of the dial which is not the center of the image
  • The hand itself is too large and needs to be scaled down
  • It will rotate not around the center of itself, but around the dot in the image

Hierarchy and positions that can be used:

[
  (dial image, default position),
  (hand group, (0.0, -125.0, 0.0) with scale (0.5),
    [
      (hand image, (0.0, 150.0, 0.0))
    ]
  )
]

Making the Car Move

While the space bar is pressed, the car speed should increase. The speedometer hand should point to the correct speed.

• Add a Resource that will hold the speed (a f32)
  • Don't forget to initialize the resource in the application
• Add a System that will increase the speed when the space bar is pressed, and decrease it when the space bar is not pressed
• Add a System that will rotate the hand based on the speed
  • You will need to rotate the hand group from above, not the hand image. A marker component can help you select the correct entity
  • Rotation is done with Quaternions
  • Quat::from_rotation_z(-speed.0 / 160.0 * 3.0 + 1.5) works well for the speedometer hand rotation