3.8 - Modeling Cameras¶
A virtual world is viewed through the lens of a virtual camera. A camera is modeled using the following information:
- location
The location of the camera in the virtual world. This is modeled by a(x,y,z)point relative to the global origin.
- orientation
The orientation of the camera determines its line-of-sight and which direction is conceptually “up”. This is modeled by defining a 3D local coordinate system defined by 3 orthogonal axes.
- projection
The projection is how 3D world coordinates are mapped to a 2D image. The two most widely used projections are orthogonal and perspective. An orthogonal projection maintains angles and distances and is useful for engineering renderings. A perspective projection models the lens of a camera and mimics the way our eyes see the real world.
WebGL Implementation¶
A virtual camera is implemented with a 4x4 transformation matrix that moves objects to their desired location and orientation in front of a camera. The transformation matrix is multiplied by an object’s vertices in your vertex shader. Modeling a camera and modeling a projection are typically done separately, but they are typically combined into a single 4x4 transformation matrix.
Glossary¶
- virtual camera
- A model of a camera that allows a view of a virtual world from a specific location and orientation.
- projection
- A mathematical operation that projects a 3D world into a 2D image.