glRenderMode(3G)glRenderMode(3G)NAMEglRenderMode - 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.
DESCRIPTIONglRenderMode() 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 con‐
tents 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 operation.
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
GL_INVALID_OPERATION is generated if glSelectBuffer() is called while
the render mode is GL_SELECT, or if glRenderMode() is called with argu‐
ment 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().
ASSOCIATED GETSglGet() with argument GL_RENDER_MODE
SEE ALSOglFeedbackBuffer(3), glInitNames(3) ,glLoadName(3), glPassThrough(3),