User's Manual

Selecting Screen Objects

141

Figure 12-1 Ray Pick Action

The shape closest to the origin of the csSeg and intersected by the line segment is

recorded in a csHit object. For information about csHit, see “Storing Selected Screen

Objects” on page 142.

Using Pick()

csCamera::pick() uses window and viewport coordinates to select the screen object

closest to the ray connecting the camera to the point. You might supply the window

coordinates using the user input methods; see “Handling User Input” on page 139.

When you supply pick() with window coordinates, the method internally uses

csContext::getViewport() to convert the coordinates to viewpoint coordinates. The

method then calls csIsectAction to construct a ray from the camera to the coordinates.

The screen object closest the camera on the ray is recorded in a csHit object. For

information about csHit, see “Storing Selected Screen Objects” on page 142.

For information about csContext::getViewport(), see “Setting the Screen Display of the

Scene” on page 97.

csPickPoints