NAME
glRenderMode
- set rasterization mode
C SPECIFICATION
GLint ggllRReennddeerrMMooddee(
GLenum _m_o_d_e )
PARAMETERS
-
_m_o_d_e
-
Specifies the rasterization mode.
Three values are accepted:
GGLL__RREENNDDEERR,
GGLL__SSEELLEECCTT, and
GGLL__FFEEEEDDBBAACCKK.
The initial value is GGLL__RREENNDDEERR.
DESCRIPTION
ggllRReennddeerrMMooddee sets the rasterization mode.
It takes one argument,
_m_o_d_e,
which can assume one of three predefined values:
-
GGLL__RREENNDDEERR
-
Render mode. Primitives are rasterized,
producing pixel fragments,
which are written into the frame buffer.
This is the normal mode
and also the default mode.
-
GGLL__SSEELLEECCTT
-
Selection mode.
No pixel fragments are produced,
and no change to the frame buffer contents is made.
Instead,
a record of the names of primitives that would have been drawn
if the render mode had been GGLL__RREENNDDEERR is returned in a select buffer,
which must be created (see ggllSSeelleeccttBBuuffffeerr) before selection mode
is entered.
-
GGLL__FFEEEEDDBBAACCKK
-
Feedback mode.
No pixel fragments are produced,
and no change to the frame buffer contents is made.
Instead,
the coordinates and attributes of vertices that would have been drawn
if the render mode had been GGLL__RREENNDDEERR is returned in a feedback buffer,
which must be created (see ggllFFeeeeddbbaacckkBBuuffffeerr) before feedback mode
is entered.
The return value of ggllRReennddeerrMMooddee is determined by the render mode at the time
ggllRReennddeerrMMooddee is called,
rather than by _m_o_d_e.
The values returned for the three render modes are as follows:
-
GGLL__RREENNDDEERR
-
0.
-
GGLL__SSEELLEECCTT
-
The number of hit records transferred to the select buffer.
-
GGLL__FFEEEEDDBBAACCKK
-
The number of values (not vertices) transferred to the feedback buffer.
See the ggllSSeelleeccttBBuuffffeerr and ggllFFeeeeddbbaacckkBBuuffffeerr reference pages for
more details concerning selection and feedback operation.
NOTES
If an error is generated,
ggllRReennddeerrMMooddee returns 0 regardless of the current render mode.
ERRORS
GGLL__IINNVVAALLIIDD__EENNUUMM is generated if _m_o_d_e is not one of the three
accepted values.
GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if ggllSSeelleeccttBBuuffffeerr is called
while the render mode is GGLL__SSEELLEECCTT,
or if ggllRReennddeerrMMooddee is called with argument GGLL__SSEELLEECCTT before
ggllSSeelleeccttBBuuffffeerr is called at least once.
GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if ggllFFeeeeddbbaacckkBBuuffffeerr is called
while the render mode is GGLL__FFEEEEDDBBAACCKK,
or if ggllRReennddeerrMMooddee is called with argument GGLL__FFEEEEDDBBAACCKK before
ggllFFeeeeddbbaacckkBBuuffffeerr is called at least once.
GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if ggllRReennddeerrMMooddee
is executed between the execution of ggllBBeeggiinn
and the corresponding execution of ggllEEnndd.
ASSOCIATED GETS
ggllGGeett with argument GGLL__RREENNDDEERR__MMOODDEE
SEE ALSO
ggllFFeeeeddbbaacckkBBuuffffeerr((33GG)),
ggllIInniittNNaammeess((33GG)),
ggllLLooaaddNNaammee((33GG)),
ggllPPaassssTThhrroouugghh((33GG)),
ggllPPuusshhNNaammee((33GG)),
ggllSSeelleeccttBBuuffffeerr((33GG))