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Set_Camera_Near_Limit


Functions

void Set_Camera_Near_Limit (double wlimit)
void UnSet_Camera_Near_Limit (void)

Function Documentation

void Set_Camera_Near_Limit ( double  wlimit  ) 

Controls the hither camera plane setting.

Parameters:
wlimit - a parametric value from 0.0 at the camera to 1.0 at the target. If 0.0 or negated, the value has special meaning (see below). Default is -0.001.

DETAILS

This function allows you to set the near clipping plane. A value approaching 0.0 will place it close to the camera position (at the cost of poor z-buffer precision), whereas a value approaching 1.0 will place it near the camera target (at the cost of clipping away anything closer than the target). A value exactly equal to 0 will let HOOPS choose a wlimit based on the precision of the zbuffer as reported by the driver.

This function can help you improve the z-buffer allocation in the scene and consequently reduce the amount of z-buffer stitching in the scene. This function is of particular use for applications which always have a large amount of empty space between the camera postion and target.

A negative value for wlimit has special meaning. The near plane starts at -wlimit but is then pushed back to the location of the nearest extremity of the bounding volume (assuming bounding volumes have not been disabled -- see Define_System_Options()). Note that since the default near limit is negative, this behavior is on by default.

NOTES

General usage should set the value as high as possible to improve Z buffer allocation as long as it doesn't clip away geometry. Architectural walkthroughs will probably want to use values near the default, while geometric modelling may work well with values in the 0.2 to 0.5 range. In other words, if developers have data that is fully enclosed within the camera frustum, higher near limits are often appropriate. Conversely, if developers are navigating in and around the objects of interest, lower near limits may be needed to avoid near-plane clipping.

RESTRICTIONS

See also:
Set_Camera, Show_Bounding_Info, UnSet_Bounding_Volume, Define_System_Options

void void UnSet_Camera_Near_Limit ( void   ) 

Removes the hither camera plane value set by a previous call to Set_Camera_Limit().

DETAILS

After a call to UnSet_Camera_Near_Limit, HOOPS 3DF will use the default camera near limit defined in Define_System_Options().

See also:
Set_Camera, Show_Bounding_Info, UnSet_Bounding_Volume, Define_System_Options

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