Adding a Camera

### 3.1.3 Adding a Camera

The `camera` statement describes where and how the camera sees the scene. It gives x-, y- and z-coordinates to indicate the position of the camera and what part of the scene it is pointing at. We describe the coordinates using a three-part vector. A vector is specified by putting three numeric values between a pair of angle brackets and separating the values with commas. We add the following camera statement to the scene.

      camera {
        location <0, 2, -3>
        look_at  <0, 1,  2>
      }

Briefly, `location <0,2,-3>` places the camera up two units and back three units from the center of the ray-tracing universe which is at <0,0,0>. By default +z is into the screen and -z is back out of the screen.

Also `look_at <0,1,2>` rotates the camera to point at the coordinates <0,1,2>. A point 1 unit up from the origin and 2 units away from the origin. This makes it 5 units in front of and 1 unit lower than the camera. The `look_at` point should be the center of attention of our image.