push_vdc_matrix(3G)

NAME

push_vdc_matrix − push VDC-to-DC transformation matrix on top of matrix stack.

SYNOPSIS

C Syntax:

void push_vdc_matrix(fildes);
int fildes;

FORTRAN77 Syntax:

subroutine push_vdc_matrix(fildes)
integer*4 fildes

Pascal Syntax:

procedure push_vdc_matrix(fildes:integer);

DESCRIPTION

Input Parameters

fildes Integer file descriptor returned by gopen when an I/O path to a graphics device is opened.

Discussion

A copy of the current VDC-to-DC transformation matrix is pushed onto the top of the matrix stack and becomes the current transformation matrix. If vdc_extent, set_p1_p2, mapping_mode, or vdc_justification changes, the internal Starbase VDC-to-DC transformation matrix changes, but not any VDC-to-DC matrices that were pushed using push_vdc_matrix.

This routine should be used carefully (especially when a device has been opened in MODEL_XFORM mode), because only modeling matrices are normally pushed on the matrix stack. If the VDC-to-DC matrix is pushed on the stack in MODEL_XFORM mode, lighting calculations for subsequent output primitives may be invalid. For lighting calculations in VDC space, use flush_matrices.

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