SilverScreenAPI

SS_COEF

Structure

A data type used to represent a plane equation of the form: AX + BY + CZ + D = 0.

struct SS_COEF

{

SS_XYZ abc;

double d;

} ;

Members

Member	Description
abc	A vector referred to as a plane normal. The x-member stores the A term from the equation above. The y-member stores the B term from the equation above. The z-member stores the C term from the equation above.
d	The d value of the plane equation.

Remarks

Given a point 'p' and a plane equation 'plane', here is how you can decide if the point is on the plane, on the + side, or on the - side. Note: There is a function which performs this calculation in the SilverScreen API called point_vs_plane and the code below is for informational purposes.

C / C++ Code

SS_XYZ p;

SS_COEF plane;

double tval;

tval = (plane.abc.x * p.x) + (plane.abc.y * p.y) + (plane.abc.z * p.z) +

plane.d;

if ( zero_double(tval) )

// The point is on the plane

else

if ( tval > 0.0 )

// The point is on the + side of the plane

else
// The point is on the - side of the plane

ssdef.h

Help URL: http://www.yourdomain.com/help/index.html?ss_coef.htm