Home › API Reference › Camera

Camera

Type	Class (Component)
Namespace	`UnityEngine`
Inherits	Behaviour > Component > Object

Camera

A Camera decides what the player sees. It also converts between screen positions (pixels, like where the mouse is) and world positions (where things are in the scene).

The camera is a window you look through at the world. The screen is the glass. ScreenPointToRay is putting your finger on the glass and asking "what am I pointing at out there?" WorldToScreenPoint is the reverse: "where on the glass do I see that tree?"

Coordinate systems

Space	Units	Example
Screen	Pixels. (0,0) bottom-left, (`Screen.width`, `Screen.height`) top-right	`Input.mousePosition`
Viewport	0 to 1. (0.5, 0.5) is the center	"Center of the screen" on any resolution
World	Scene units (meters)	`transform.position`

Screen and viewport coordinates both start at the bottom-left, in pixels or 0 to 1. ScreenPointToRay turns a point on the screen into a ray from the camera into the world; pass it to Physics.Raycast to find what's under the mouse.

Static Properties

Name	Type	Description
`Camera.main`	`Camera`	The first enabled camera tagged "MainCamera". `null` if none is tagged.

Properties

Name	Type	Description
`fieldOfView`	`float`	Vertical view angle in degrees (perspective). Lower = zoomed in.
`orthographic`	`bool`	True for flat 2D-style views with no perspective.
`orthographicSize`	`float`	Half the height of the view in world units (orthographic). Lower = zoomed in.
`nearClipPlane` / `farClipPlane`	`float`	Things closer/further than these aren't drawn.
`backgroundColor`	`Color`	Fill color when Clear Flags / Background Type is Solid Color.
`cullingMask`	`int`	Which layers this camera draws.
`depth`	`float`	Draw order when there are several cameras (Built-in pipeline). Higher draws on top.

Methods

Method	Returns	Description
`ScreenPointToRay(Vector3 pos)`	`Ray`	A ray from the camera through a screen pixel. Use with `Physics.Raycast` for mouse picking.
`ViewportPointToRay(Vector3 pos)`	`Ray`	Same with viewport coordinates. (0.5, 0.5) = crosshair.
`ScreenToWorldPoint(Vector3 pos)`	`Vector3`	Pixel → world. `pos.z` must be the distance from the camera.
`WorldToScreenPoint(Vector3 pos)`	`Vector3`	World → pixel. `z` is the distance; negative means behind the camera.
`WorldToViewportPoint(Vector3 pos)`	`Vector3`	World → 0-1 viewport. Handy for "is this on screen?"

Code Samples

2D: move an object to the mouse

using UnityEngine;

public class FollowMouse2D : MonoBehaviour
{
    private Camera cam;

    void Awake() { cam = Camera.main; } // cache it

    void Update()
    {
        Vector3 mouse = Input.mousePosition;
        mouse.z = -cam.transform.position.z; // distance from camera to the z = 0 plane
        Vector3 world = cam.ScreenToWorldPoint(mouse);
        transform.position = new Vector3(world.x, world.y, 0f);
    }
}

Health bar over an enemy's head (Screen Space UI)

[SerializeField] private Transform enemyHead;
[SerializeField] private RectTransform healthBarUI;

void LateUpdate()
{
    Vector3 screen = Camera.main.WorldToScreenPoint(enemyHead.position);
    bool inFront = screen.z > 0f;
    healthBarUI.gameObject.SetActive(inFront);
    if (inFront) healthBarUI.position = screen;
}

Is an object on screen?

Vector3 v = cam.WorldToViewportPoint(target.position);
bool onScreen = v.z > 0f && v.x >= 0f && v.x <= 1f && v.y >= 0f && v.y <= 1f;

What happens at runtime

After LateUpdate, every enabled camera renders what it can see on its cullingMask layers, between its near and far clip planes.
That's why camera movement belongs in LateUpdate: everything has moved for this frame, and the camera renders right after.
Camera.main is cached by Unity in recent versions, so it's cheap, but it's still tidy to store it in a field.

Common Mistakes

Camera.main is null. Your camera isn't tagged "MainCamera".
ScreenToWorldPoint always returns the camera position. You left z = 0. For a perspective camera, z must be how far in front of the camera you want the point.
Jittery follow camera. Move it in LateUpdate, and if following a Rigidbody, turn on Interpolate on that Rigidbody.
For polished cameras, consider the Cinemachine package: follow, look-at, screen shake and blending between shots without code.

Camera

Coordinate systems

Static Properties

Properties

Methods

Code Samples

2D: move an object to the mouse

Health bar over an enemy's head (Screen Space UI)

Is an object on screen?

What happens at runtime

Common Mistakes

See also