DragonFly On-Line Manual Pages

BUGLE-CAMERA(7)                Bugle user manual               BUGLE-CAMERA(7)

NAME
       bugle-camera - allow the camera to be manipulated

SYNOPSIS
       filterset camera [key inactive]
       {
           speed "1.0"
           mouse_dga "no"
       }

DESCRIPTION
       This filter-set allows you to take over the camera in an OpenGL
       application and move it about. This is particularly useful for testing
       visibility culling and level-of-detail (LOD), as these will not change
       as the camera is moved.

       To use it, make sure it is activated, then move to the mouse to control
       the camera angle and the Up, Down, Left and Right keys to move the
       viewpoint. The camera model is a free camera, so it will not maintain a
       defined up direction. There are a few other useful keys, described in
       the section called "OPTIONS".

       This filter-set supports activation and deactivation; the recommended
       use is to have it initially inactive and use a key to take over control
       when desired (see bugle(3)).

       Since this filter-set is based on modifying OpenGL state without
       telling the application, there are significant limitations:

       o   The projection matrix, and in particular, the near and far clip
           planes, are not altered. Thus, trying to move in too close or out
           too far could cause objects to be clipped away.

       o   Various fancy rendering techniques involve rendering a quad that is
           carefully aligned to the screen; altering the camera will break
           such techniques. There is ultimately no general fix as it is
           impossible to know when an application is dealing with the real
           world. If you are writing such an application and wish it to work
           with this filter-set, you should use a vertex program that ignores
           the model-view matrix in situations where you do not want this
           filter-set to interfere.

       o   Applications that rely on the feedback buffer are likely to break.

OPTIONS
       mouse_dga
           This is a boolean option which should be enabled when debugging an
           application that uses XDGA(3) to get relative motion data from the
           mouse. If the camera goes all over the place as soon as you move
           the mouse, try enabling this option (SDL-based applications are the
           main culprits).

       speed
           This sets the speed at which the camera moves. Since each
           application has a different scale, you will need to adjust the
           value for each application (but dynamic control is also possible;
           see below).

       key_forward, key_back, key_left, key_right
           These are the keys for moving the camera. They default to the arrow
           keys.

       key_faster, key_slower
           These keys control the speed of the camera, doubling or halving it
           respectively. They default to PageUp and PageDown.

       key_reset
           This key cancels any alterations made, restoring the camera to
           where the application thinks it is. There is no default.

       key_toggle
           This key alternately releases and recaptures the mouse. It can be
           useful if you need to use the mouse in another window without
           completely disabling the filter-set (which would also restore the
           camera position). There is no default.

           This toggles display of the original view frustum. If this driver
           supports GL_NV_depth_clamp, depth clamping is used to prevent the
           frustum from being clipped to the near and far clip planes. There
           is no default.

AUTHOR
       bugle is written and maintained by Bruce Merry.

SEE ALSO
       bugle(3)

BUGLE 0.0.20091026               October 2007                  BUGLE-CAMERA(7)