NAME
fglRenderMode - set rasterization mode
FORTRAN SPECIFICATION
INTEGER*4 fglRenderMode( INTEGER*4 mode )
PARAMETERS
mode Specifies the rasterization mode. Three values are
accepted: GL_RENDER, GL_SELECT, and GL_FEEDBACK. The
initial value is GL_RENDER.
DESCRIPTION
fglRenderMode sets the rasterization mode. It takes one
argument, mode, which can assume one of three predefined
values:
GL_RENDER 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.
GL_SELECT 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 GL_RENDER
is returned in a select buffer, which must
be created (see fglSelectBuffer) before
selection mode is entered.
GL_FEEDBACK 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
GL_RENDER is returned in a feedback buffer,
which must be created (see
fglFeedbackBuffer) before feedback mode is
entered.
The return value of fglRenderMode is determined by the
render mode at the time fglRenderMode is called, rather than
by mode. The values returned for the three render modes are
as follows:
GL_RENDER 0.
GL_SELECT The number of hit records transferred to the
select buffer.
GL_FEEDBACK The number of values (not vertices)
transferred to the feedback buffer.
See the fglSelectBuffer and fglFeedbackBuffer reference
pages for more details concerning selection and feedback
operation.
NOTES
If an error is generated, fglRenderMode returns 0 regardless
of the current render mode.
ERRORS
GL_INVALID_ENUM is generated if mode is not one of the three
accepted values.
GL_INVALID_OPERATION is generated if fglSelectBuffer is
called while the render mode is GL_SELECT, or if
fglRenderMode is called with argument GL_SELECT before
fglSelectBuffer is called at least once.
GL_INVALID_OPERATION is generated if fglFeedbackBuffer is
called while the render mode is GL_FEEDBACK, or if
fglRenderMode is called with argument GL_FEEDBACK before
fglFeedbackBuffer is called at least once.
GL_INVALID_OPERATION is generated if fglRenderMode is
executed between the execution of fglBegin and the
corresponding execution of fglEnd.
ASSOCIATED GETS
fglGet with argument GL_RENDER_MODE
SEE ALSO
fglFeedbackBuffer, fglInitNames, fglLoadName,
fglPassThrough, fglPushName, fglSelectBuffer