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  • Cameras.

  • The camera is one of the most

  • essential components in Unity.

  • The camera takes the contents of our scene

  • and displays it to our users.

  • Every scene must have at least

  • one camera to render out scene objects

  • otherwise we have nothing to show.

  • When a new scene is created

  • one game object is always created.

  • This is the main camera.

  • The game view camera is a

  • component attached to a game object.

  • This means we can manipulate, or move our camera

  • like any other game object,

  • including parenting, scripting,

  • or physical interaction.

  • To create a first or third person camera,

  • including side scrollers,

  • we can use the player object as the parent.

  • For first person cameras, make sure the camera

  • is at the character's eye height

  • looking forward from the character's point of view.

  • For a third person view, make sure the camera is

  • above and behind the character.

  • For a simple puzzle game or top-down shooter

  • the camera would be static, simply

  • looking at and rendering the game.

  • In this example we are going to centre the camera,

  • remove any unwanted rotation,

  • point it straight down and lift it above

  • the game board to simulate a top-down game.

  • In this case we are using the orthographic

  • mode on the camera, which we will cover

  • later in this lesson.

  • We can have any number of cameras in our scene.

  • Each rendering different parts of the environment.

  • In this example we have three cameras.

  • One rendering all of the dynamic

  • objects in the scene. Another rendering

  • the static background and a third

  • rendering a User Interface overlay.

  • All three cameras can be brought together to

  • make a single presentation to our user.

  • We will talk about how to properly use all

  • three cameras at once later on in this lesson.

  • When a camera is selected in the hierarchy

  • we see a preview of the camera in the scene.

  • When we have multiple cameras in the scene

  • this helps us to see what the camera is rendering.

  • This preview is also helpful when we are in

  • full screen mode to see what the camera is rendering,

  • even if it's the only camera in the scene.

  • Cameras will render everything that's in

  • front of them and within their view.

  • How much of the scene is within their view

  • is shown in the scene view as a white outline.

  • This shape is a view frustum.

  • A view frustum is a pyramid, or cone,

  • with the top cut off.

  • The cut off top of the pyramid is the

  • near clipping plane and the base

  • is the far clipping plane.

  • The near and far clipping planes control

  • the draw distance from the camera.

  • Objects must be between the near and far

  • clipping planes to be rendered. The sides

  • indicate how much the camera can see

  • side to side and top to bottom.

  • and any part of the scene that's within

  • the frustum will be rendered.

  • Cameras have two different ways of

  • looking at the scene. Perspective mode

  • and orthographic mode.

  • These dramatically effect the shape and

  • size of the frustum and the

  • look of the scene through the camera.

  • In perspective mode the camera will render

  • the scene like a real world camera with

  • a sense of diminishing perspective.

  • We can see this in the scene view as the

  • white representation of the cameras

  • frustum gets larger as it extends

  • away from the camera.

  • This is the most common camera mode to use

  • when creating a game.

  • In orthographic mode there is no

  • diminishing perspective. All objects are

  • rendered using a form of parallel

  • projection from the camera. We can see this

  • in the scene view as the frustum is straight

  • and the front and back are the same size.

  • This mode is usually seen in isometric

  • games like some real time strategy or

  • board games, or for 2D

  • games, simple puzzle games and when using

  • an additional camera for rendering UI elements

  • on top of the game view, like mini

  • maps or heads-up displays.

  • To control what is being rendered in our

  • scenes, adjust the near and far clipping

  • planes and the size or shape of the frustum.

  • Field Of View controls how wide the view

  • of the camera will be. This is very much

  • like using the zoom on a real world camera.

  • When the camera is in orthographic mode

  • size replaces the field of view property.

  • This controls the size of the

  • orthographic viewport.

  • This is similar to field of view but

  • the value of the size property changes

  • the size of both the front and back planes

  • at the same time as there is no perspective

  • with an orthographic camera.

  • Our scenes must have some sort of a background.

  • This controlled by the Clear Flags and

  • Background properties.

  • The colour values set in the background

  • property will be what's drawn behind any

  • of the objects in our scene, if no other

  • settings have been changed. This is the

  • default blue colour we see in a new empty scene.

  • Clear Flags determines what the background

  • will be for a camera. This setting is particularly

  • important when using multiple cameras.

  • Each camera stores colour and depth information

  • when it renders it's view. The portions of the

  • screen that are not drawn upon are considered empty.

  • The Clear Flags property will determine

  • what is shown in this empty space.

  • If we have a skybox set in our render

  • settings the background will be a skybox.

  • Skybox is the default clear flag for any camera.

  • A skybox is a material that contains

  • several images that surround the entire scene

  • providing a textured background for that scene.

  • For more information on skyboxes and

  • render settings see the appropriate lessons.

  • If we don't have a skybox set, or we choose

  • solid colour as our clear flag.

  • The colour value from the background property

  • will be used behind any of our objects

  • in the scene.

  • Depth Only is primarily used for

  • multiple cameras. We will cover depth only

  • in a moment.

  • Don't Clear will result in each frame

  • being drawn over the last, creating

  • a smear effect. This setting isn't typically

  • used in games.

  • When using multiple cameras the most practical

  • setting for clear flags is depth only.

  • With this setting each camera is given a

  • value and depth and the contents of each

  • camera's view are layered on top of each other

  • in depth order, starting with

  • lowest depth first.

  • Normally the main camera is assigned

  • the lowest depth value

  • and has it's clear flag set to either

  • skybox or solid colour.

  • All of the other cameras have their clear

  • flags set to depth only. This way there is

  • one ultimate background, and the images

  • of all the other cameras are

  • layered on top of the main camera.

  • The content of what the camera is rendering

  • is limited by the Culling Mask property.

  • The Culling Mask drop down will list

  • all the layers available in the scene.

  • The camera will render only those objects

  • on the layers selected in it's culling mask.

  • For more information on layers and how to

  • use then see the appropriate lesson.

  • In the case of the User Interface overlay

  • we have the interface element set to the

  • UI layer. Our UI camera has it's culling mask

  • set to render only the objects on the User Interface layer

  • We have our clear flag set to depth only

  • and the depth set to the highest value

  • of all the cameras in the scene.

  • This way the UI camera only draws

  • the UI element based on the culling mask

  • setting and the UI element draws on top

  • of all of the other layers, based on the depth.

  • It is also worth noting that the camera is set to

  • orthographic to remove any possible

  • perspective on the UI element.

  • Typical uses of multiple cameras

  • are to render UI elements like

  • mini maps or heads-up displays over the

  • world view, make rear-view mirrors and

  • missile cameras, or to force the drawing order

  • of objects in the scene, like making

  • sure that a gun in a first person shooter

  • doesn't get drawn inside the level geometry.

  • The normalised viewport rect, render path,

  • target texture and HDR properties

  • are more advanced and will be covered in an other lesson.

Cameras.

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