gluProject.3G - Man Page

map object coordinates to window coordinates

C Specification

GLint gluProject( GLdouble objX,

	GLdouble objY,
	GLdouble objZ,
	const GLdouble *model,
	const GLdouble *proj,
	const GLint *view,
	GLdouble* winX,
	GLdouble* winY,
	GLdouble* winZ )

Parameters

objX, objY, objZ

Specify the object coordinates.

model

Specifies the current modelview matrix (as from a glGetDoublev call).

proj

Specifies the current projection matrix (as from a glGetDoublev call).

view

Specifies the current viewport (as from a glGetIntegerv call).

winX, winY, winZ

Return the computed window coordinates.

Description

gluProject transforms the specified object coordinates into window coordinates using model, proj, and view. The result is stored  in winX, winY, and winZ. A return value of  GL_TRUE indicates success, a return value of GL_FALSE indicates failure.

To compute the coordinates, let v=(objX,objY,objZ,1.0) represented as a matrix with 4 rows and 1 column. Then gluProject computes v as follows:

v=P×M×v

where P is the current projection matrix proj, M is the current modelview matrix model (both represented as 4×4 matrices in column-major order) and '×' represents matrix multiplication.

The window coordinates are then computed as follows:

winX=view(0)+view(2)*(v(0)+1)/2

winY=view(1)+view(3)*(v(1)+1)/2

winZ=(v(2)+1)/2

See Also

glGet(3G), gluUnProject(3G)

Referenced By

gluUnProject.3G(3), gluUnProject4.3G(3).