glRenderMode - set rasterization mode
GLenum mode );
Specifies the rasterization mode. Three values are
accepted: GL_RENDER, GL_SELECT, and GL_FEEDBACK. The initial
value is GL_RENDER.
glRenderMode() sets the rasterization mode. It takes one
argument, mode, which can assume one of three predefined
values: 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. 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 glSelectBuffer())
before selection mode is entered. 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 glFeedbackBuffer())
before feedback mode is entered.
The return value of glRenderMode() is determined by the
render mode at the time glRenderMode() is called, rather
than by mode. The values returned for the three render
modes are as follows: 0. The number of hit records transferred
to the select buffer. The number of values (not
vertices) transferred to the feedback buffer.
See the glSelectBuffer() and glFeedbackBuffer() reference
pages for more details concerning selection and feedback
If an error is generated, glRenderMode() returns 0 regardless
of the current render mode.
GL_INVALID_ENUM is generated if mode is not one of the
three accepted values.
GL_INVALID_OPERATION is generated if glSelectBuffer() is
called while the render mode is GL_SELECT, or if glRenderMode()
is called with argument GL_SELECT before glSelectBuffer()
is called at least once.
GL_INVALID_OPERATION is generated if glFeedbackBuffer() is
called while the render mode is GL_FEEDBACK, or if glRenderMode()
is called with argument GL_FEEDBACK before
glFeedbackBuffer() is called at least once.
GL_INVALID_OPERATION is generated if glRenderMode() is
executed between the execution of glBegin() and the
corresponding execution of glEnd().
glGet() with argument GL_RENDER_MODE
glFeedbackBuffer(3), glInitNames(3) ,glLoadName(3),
glPassThrough(3), glPushName(3), glSelectBuffer(3)
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