gluProject(3G) OpenGL Reference gluProject(3G)
NAME
gluProject - 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 GLTRUE indicates success, a return
value of GLFALSE 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 x M x v
where P is the current projection matrix proj, M is the current modelview
matrix model (both represented as 4x4 matrices in column-major order) and
'x' represents matrix multiplication.
The window coordinates are then computed as follows:
'
winX = view(0) + view(2) * (v (0) + 1) / 2
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gluProject(3G) OpenGL Reference gluProject(3G)
'
winY = view(1) + view(3) * (v (1) + 1) / 2
'
winZ = (v (2) + 1) / 2
SEE ALSO
glGet, gluUnProject
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