graPHIGS Programming Interface: Subroutine Reference

The graPHIGS Programming Interface : Subroutine Reference

GPEVM3 - Evaluate View Mapping Matrix 3

GPEVM3 (window, viewpt, type, point, dist, near, far, errind, matrix)

Purpose

Use GPEVM3 to create a view mapping matrix. The matrix can be used as input to the Set Extended View Representation (GPXVR) subroutine.

If the view mapping matrix can be computed, the error indicator is set to zero, and the matrix is returned. If the matrix cannot be computed, the error indicator contains an error number indicating the reason. In this case, the value of the output parameter is unpredictable.

Parameters

window -- specified by user, 4 short floating-point numbers (VC)

Window limits (Umin, Umax, Vmin, Vmax)

viewpt -- specified by user, 6 short floating-point numbers (NPC)

Viewport limits (Xmin, Xmax, Ymin, Ymax, Zmin, Zmax)

type -- specified by user, fullword integer

Projection type (1=PARALLEL, 2=PERSPECTIVE )

point -- specified by user, 3 short floating point numbers (VC)

Projection reference point (U, V, N)

dist -- specified by user, short floating-point number (VC)

Distance of view plane from view reference point along n-axis.

near -- specified by user, short floating-point number (VC)

Distance of near plane from view reference point along n-axis.

far -- specified by user, short floating-point number (VC)

Distance of far plane from view reference point along n-axis.

errind -- returned by the graPHIGS API, fullword integer

If the error indicator is zero, the request has been completed. Otherwise, one of the following errors exists:

44: INVALID WINDOW DEFINITION
55: PRP IS POSITIONED ON THE VIEW PLANE
330: INVALID VIEWPORT
331: PROJECTION TYPE IS INVALID
336: FAR CLIPPING PLANE IN FRONT OF NEAR CLIPPING PLANE
608: FRONT PLANE DISTANCE = BACK PLANE DISTANCE WHEN Z-EXTENT NON-ZERO
610: PROJECTION REFERENCE POINT BETWEEN NEAR AND FAR PLANES

matrix -- returned by the graPHIGS API, 16 short floating-point numbers

View mapping matrix. The elements are returned in the following order for the view mapping matrix:

                 
  |m11 m12 m13 m14|
  |m21 m22 m23 m24| ---> (m11,m12,m13,m14,m21,m22,...m44)
  |m31 m32 m33 m34|
  |m41 m42 m43 m44|

Error Codes

None

Related Subroutines

GPXVR: Set Extended View Representation

RCP code

201331207 (X'0C001207')