GLPASSTHROUGH(3G)GLPASSTHROUGH(3G)NAME
glPassThrough - place a marker in the feedback buffer
C SPECIFICATION
void glPassThrough( GLfloat token )
PARAMETERS
token Specifies a marker value to be placed in the feedback buffer following a GL_PASS_THROUGH_TOKEN.
DESCRIPTION
Feedback is a GL render mode. The mode is selected by calling glRenderMode with GL_FEEDBACK. When the GL is in feedback mode, no pixels
are produced by rasterization. Instead, information about primitives that would have been rasterized is fed back to the application using
the GL. See the glFeedbackBuffer reference page for a description of the feedback buffer and the values in it.
glPassThrough inserts a user-defined marker in the feedback buffer when it is executed in feedback mode. token is returned as if it were a
primitive; it is indicated with its own unique identifying value: GL_PASS_THROUGH_TOKEN. The order of glPassThrough commands with respect
to the specification of graphics primitives is maintained.
NOTES
glPassThrough is ignored if the GL is not in feedback mode.
ERRORS
GL_INVALID_OPERATION is generated if glPassThrough is executed between the execution of glBegin and the corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GL_RENDER_MODE
SEE ALSO glFeedbackBuffer(3G), glRenderMode(3G)GLPASSTHROUGH(3G)
Check Out this Related Man Page
GLRENDERMODE(3G)GLRENDERMODE(3G)NAME
glRenderMode - set rasterization mode
C SPECIFICATION
GLint glRenderMode( GLenum 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
glRenderMode 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 glSelectBuffer) 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 coordi-
nates 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:
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 glSelectBuffer and glFeedbackBuffer reference pages for more details concerning selection and feedback operation.
NOTES
If an error is generated, glRenderMode 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 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 GETS
glGet with argument GL_RENDER_MODE
SEE ALSO
glFeedbackBuffer, glInitNames, glLoadName, glPassThrough, glPushName, glSelectBuffer
GLRENDERMODE(3G)