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The graPHIGS Programming Interface : Subroutine Reference

GPDM2 - Set Data Matrix 2

GPDM2 (matrix)

Purpose

Use GPDM2 to insert a Set Data Matrix 2 structure element into the open structure following the element pointer, or to replace the element pointed at by the element pointer with a Set Data Matrix 2 structure element, depending upon the current edit mode.

This element specifies the transformation matrix that the graPHIGS API uses to modify the data mapping values specified in primitives that support data mapping.

The data mapping values are treated as homogeneous points of the form (u, v, 1.0). When used with a data mapping method of 2=SINGLE_VALUE_UNIFORM , the graPHIGS API sets the v coordinate value to 0.0. Otherwise, the graPHIGS API uses indexed vertex data values for the u and v coordinate values. This point is multiplied by the specified matrix. The resulting values are used to perform the data mapping.

The last column of the matrix must have the values 0.0, 0.0, 1.0.

The traversal default data matrix is the identity matrix.

Parameters

matrix -- specified by user, 9 short floating-point numbers

Data modification matrix.

The elements of the matrix must be specified as follows:

|m11  M12  0.0|
|m21  M22  0.0| ---> (m11, m12, 0.0, m21, m22, 0.0, m31, m32, 1.0)
|m31  M32  1.0|

Error Codes

5
FUNCTION REQUIRES STATE STOP OR NROP (NOT STCL)
633
MATRIX VALUE IS INVALID

Related Subroutines

GPBDM2
Set Back Data Matrix 2
GPDMR
Set Data Mapping Representation

RCP code

201343517 (X'0C00421D')


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