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<STRONG>NAME</STRONG>
<STRONG>glRenderMode</STRONG> - set rasterization mode
<STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>
GLint <STRONG>glRenderMode</STRONG>( GLenum <EM>mode</EM> )
<STRONG>PARAMETERS</STRONG>
<EM>mode</EM> Specifies the rasterization mode. Three values are
accepted: <STRONG>GL_RENDER</STRONG>, <STRONG>GL_SELECT</STRONG>, and <STRONG>GL_FEEDBACK</STRONG>. The
initial value is <STRONG>GL_RENDER</STRONG>.
<STRONG>DESCRIPTION</STRONG>
<STRONG>glRenderMode</STRONG> sets the rasterization mode. It takes one
argument, <EM>mode</EM>, which can assume one of three predefined
values:
<STRONG>GL_RENDER</STRONG> 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.
<STRONG>GL_SELECT</STRONG> 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 <STRONG>GL_RENDER</STRONG>
is returned in a select buffer, which must
be created (see <STRONG>glSelectBuffer</STRONG>) before
selection mode is entered.
<STRONG>GL_FEEDBACK</STRONG> 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
<STRONG>GL_RENDER</STRONG> is returned in a feedback buffer,
which must be created (see <STRONG>glFeedbackBuffer</STRONG>)
before feedback mode is entered.
The return value of <STRONG>glRenderMode</STRONG> is determined by the render
mode at the time <STRONG>glRenderMode</STRONG> is called, rather than by
<EM>mode</EM>. The values returned for the three render modes are as
follows:
<STRONG>GL_RENDER</STRONG> 0.
<STRONG>GL_SELECT</STRONG> The number of hit records transferred to the
select buffer.
<STRONG>GL_FEEDBACK</STRONG> The number of values (not vertices)
transferred to the feedback buffer.
See the <STRONG>glSelectBuffer</STRONG> and <STRONG>glFeedbackBuffer</STRONG> reference pages
for more details concerning selection and feedback
operation.
<STRONG>NOTES</STRONG>
If an error is generated, <STRONG>glRenderMode</STRONG> returns 0 regardless
of the current render mode.
<STRONG>ERRORS</STRONG>
<STRONG>GL_INVALID_ENUM</STRONG> is generated if <EM>mode</EM> is not one of the three
accepted values.
<STRONG>GL_INVALID_OPERATION</STRONG> is generated if <STRONG>glSelectBuffer</STRONG> is
called while the render mode is <STRONG>GL_SELECT</STRONG>, or if
<STRONG>glRenderMode</STRONG> is called with argument <STRONG>GL_SELECT</STRONG> before
<STRONG>glSelectBuffer</STRONG> is called at least once.
<STRONG>GL_INVALID_OPERATION</STRONG> is generated if <STRONG>glFeedbackBuffer</STRONG> is
called while the render mode is <STRONG>GL_FEEDBACK</STRONG>, or if
<STRONG>glRenderMode</STRONG> is called with argument <STRONG>GL_FEEDBACK</STRONG> before
<STRONG>glFeedbackBuffer</STRONG> is called at least once.
<STRONG>GL_INVALID_OPERATION</STRONG> is generated if <STRONG>glRenderMode</STRONG> is
executed between the execution of <STRONG>glBegin</STRONG> and the
corresponding execution of <STRONG>glEnd</STRONG>.
<STRONG>ASSOCIATED</STRONG> <STRONG>GETS</STRONG>
<STRONG>glGet</STRONG> with argument <STRONG>GL_RENDER_MODE</STRONG>
<STRONG>SEE</STRONG> <STRONG>ALSO</STRONG>
<STRONG>glFeedbackBuffer</STRONG>, <STRONG>glInitNames</STRONG>, <STRONG>glLoadName</STRONG>, <STRONG>glPassThrough</STRONG>,
<STRONG>glPushName</STRONG>, <STRONG>glSelectBuffer</STRONG>
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