Unity – Tanks Tutorial Part 3

Hey folks, we had a quite complicated session this week which discussed a lot of new concepts.

Screen Shot 2016-03-13 at 21.07.33Screen Shot 2016-03-13 at 21.07.10

We talked about the difference between perspective cameras and orthogonal cameras. With perspective cameras, as shown in the first image above, things appear smaller the further they are from the camera. With an orthogonal camera, as shown above in the second image, they appear the same size, regardless of how far they are from the camera.

The screen, and by extension, the camera which draws into that screen has an aspect ratio. This is defined as the width divided by the height. For example, a standard 1080p HD screen of has 1920 x 1024 pixels. This is an aspect ratio of 1.875. Our aspect ratio depends on how we’ve sized our game panel.

The camera in the tanks game is an orthogonal camera and the amount it can see is determined by it’s size. Whatever the camera’s size is, twice that distance in world units will be shown vertically by the camera. Our camera’s size is 5 so that means we can see 10 world distance units vertically and (10 x aspect ratio) distance units horizontally.

The code we showed the last day tries to position the camera at the average position between the tanks and size it so that both tanks fit in at the same time.

One unusual thing  that it does is to ensure smooth movement of the camera by not jumping it instantly to the place we want it to be, or the size we want it to be, but rather using the Vector3.SmoothDamp() method. This method allows us to specify two vectors, one representing the current value and the second representing value we’d like to get to, and returns a vectors that is someway from the first to the second such that it gives a smooth, as opposed to sudden or jerky, movement:

        transform.position = Vector3.SmoothDamp(transform.position, 
                                                m_DesiredPosition, 
                                                ref m_MoveVelocity, m_DampTime);

 

I’ve completed the health bar, as promised, and we won’t be doing that at Dojo. Just download the up-to-date project file from here, and we will start with it next week.

Remember to be working on your own projects! See you next week.

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