3D Graphics Programming with QuickDraw 3D 1.5.4

Determining Point Relative Ratios

QuickDraw 3D provides routines that you can use to determine point-relative ratios between two points. These routines return a point on the line segment defined by those two points that is at a desired distance from the first point.

Q3Point2D_RRatio

You can use the Q3Point2D_RRatio function to find a point lying between two given two-dimensional points that is at a desired distance ratio from one of those points.



 
TQ3Point2D *Q3Point2D_RRatio (

                     const TQ3Point2D *p1, 

                     const TQ3Point2D *p2, 

                     float r1, 

                     float r2, 

                     TQ3Point2D *result);

p1: A two-dimensional point.
p2: A two-dimensional point.
r1: A floating-point number.
r2: A floating-point number.
result: On exit, the two-dimensional point that is at a desired distance ratio from p1 along the line segment between p1 and p2 .

DESCRIPTION

The Q3Point2D_RRatio function returns, as its function result and in the result parameter, the two-dimensional point that lies on the line segment between the points p1 and p2 and that is at a distance from the first point determined by the ratio r1 /(r1 + r2 ).

Q3Param2D_RRatio

You can use the Q3Param2D_RRatio function to find a point lying between two given two-dimensional parametric points that is at a desired distance ratio from one of those points.



 
TQ3Param2D *Q3Param2D_RRatio (

                     const TQ3Param2D *p1, 

                     const TQ3Param2D *p2, 

                     float r1, 

                     float r2, 

                     TQ3Param2D *result);

p1: A two-dimensional parametric point.
p2: A two-dimensional parametric point.
r1: A floating-point number.
r2: A floating-point number.
result: On exit, the two-dimensional parametric point that is at a desired distance ratio from p1 along the line segment between p1 and p2 .

DESCRIPTION

The Q3Param2D_RRatio function returns, as its function result and in the result parameter, the two-dimensional parametric point that lies on the line segment between the points p1 and p2 and that is at a distance from the first parametric point determined by the ratio r1 /(r1 + r2 ).

Q3Point3D_RRatio

You can use the Q3Point3D_RRatio function to find a point lying between two given three-dimensional points that is at a desired distance ratio from one of those points.



 
TQ3Point3D *Q3Point3D_RRatio (

                     const TQ3Point3D *p1, 

                     const TQ3Point3D *p2, 

                     float r1, 

                     float r2, 

                     TQ3Point3D *result);

p1: A three-dimensional point.
p2: A three-dimensional point.
r1: A floating-point number.
r2: A floating-point number.
result: On exit, the three-dimensional point that is at a desired distance ratio from p1 along the line segment between p1 and p2 .

DESCRIPTION

The Q3Point3D_RRatio function returns, as its function result and in the result parameter, the three-dimensional point that lies on the line segment between the points p1 and p2 and that is at a distance from the first point determined by the ratio r1 /(r1 + r2 ).

Q3RationalPoint4D_RRatio

You can use the Q3RationalPoint4D_RRatio function to find a point lying between two given four-dimensional points that is at a desired distance ratio from one of those points.



 
TQ3RationalPoint4D *Q3RationalPoint4D_RRatio (

                     const TQ3RationalPoint4D *p1, 

                     const TQ3RationalPoint4D *p2, 

                     float r1, 

                     float r2, 

                     TQ3RationalPoint4D *result);

p1: A rational four-dimensional point.
p2: A rational four-dimensional point.
r1: A floating-point number.
r2: A floating-point number.
result: On exit, the four-dimensional point that is at a desired distance ratio from p1 along the line segment between p1 and p2 .

DESCRIPTION

The Q3RationalPoint4D_RRatio function returns, as its function result and in the result parameter, the four-dimensional point that lies on the line segment lying between the points p1 and p2 and that is at a distance from the first point determined by the ratio r1 /(r1 + r2 ).