NAME
glOrtho
- multiply the current matrix with an orthographic matrix
C SPECIFICATION
void ggllOOrrtthhoo(
GLdouble _l_e_f_t,
GLdouble _r_i_g_h_t,
GLdouble _b_o_t_t_o_m,
GLdouble _t_o_p,
GLdouble _n_e_a_r___v_a_l,
GLdouble _f_a_r___v_a_l )
PARAMETERS
-
_l_e_f_t, _r_i_g_h_t
-
Specify the coordinates for the left and right vertical clipping planes.
-
_b_o_t_t_o_m, _t_o_p
-
Specify the coordinates for the bottom and top horizontal clipping planes.
-
_n_e_a_r___v_a_l, _f_a_r___v_a_l
-
Specify the distances to the nearer and farther depth clipping planes.
These values are negative if the plane is to be behind the viewer.
DESCRIPTION
ggllOOrrtthhoo describes a transformation that produces a parallel projection.
The current matrix (see ggllMMaattrriixxMMooddee) is multiplied by this matrix
and the result replaces the current matrix, as if
ggllMMuullttMMaattrriixx were called with the following matrix
as its argument:
left ( matrix {
ccol { {2 over {"right" - "left"}} above 0 above 0 above 0 }
ccol { 0 above {2 over {"top" - "bottom"}} above 0 above 0 }
ccol { 0 above 0 above {-2 over {"far_val" - "near_val"}} above 0 }
ccol { {t sub x}~ above {t sub y}~ above {t sub z}~ above 1~ }
} right )
where
t sub x ~=~ -^{{"right" ~+~ "left"} over {"right" ~-~ "left"}}
t sub y ~=~ -^{{"top" ~+~ "bottom"} over {"top" ~-~ "bottom"}}
t sub z ~=~ -^{{"far_val" ~+~ "near_val"} over {"far_val" ~-~ "near_val"}}
Typically, the matrix mode is GGLL__PPRROOJJEECCTTIIOONN, and
(_l_e_f_t, _b_o_t_t_o_m, -_n_e_a_r___v_a_l) and (_r_i_g_h_t, _t_o_p, -_n_e_a_r___v_a_l)
specify the points on the near clipping plane that are mapped
to the lower left and upper right corners of the window,
respectively,
assuming that the eye is located at (0, 0, 0).
-_f_a_r___v_a_l specifies the location of the far clipping plane.
Both _n_e_a_r___v_a_l and _f_a_r___v_a_l can be either positive or negative.
Use ggllPPuusshhMMaattrriixx and ggllPPooppMMaattrriixx to save and restore
the current matrix stack.
ERRORS
GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if ggllOOrrtthhoo
is executed between the execution of
ggllBBeeggiinn
and the corresponding execution of ggllEEnndd.
ASSOCIATED GETS
ggllGGeett with argument GGLL__MMAATTRRIIXX__MMOODDEE
ggllGGeett with argument GGLL__CCOOLLOORR__MMAATTRRIIXX
ggllGGeett with argument GGLL__MMOODDEELLVVIIEEWW__MMAATTRRIIXX
ggllGGeett with argument GGLL__PPRROOJJEECCTTIIOONN__MMAATTRRIIXX
ggllGGeett with argument GGLL__TTEEXXTTUURREE__MMAATTRRIIXX
SEE ALSO
ggllFFrruussttuumm((33GG)),
ggllMMaattrriixxMMooddee((33GG)),
ggllMMuullttMMaattrriixx((33GG)),
ggllPPuusshhMMaattrriixx((33GG)),
ggllVViieewwppoorrtt((33GG))