MirOS Manual: glRenderMode(3)


GLRENDERMODE(3G)    UNIX Programmer's Manual     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 argu-
     ment, mode, which can assume one of three predefined values:

     GL_RENDER       Render mode. Primitives are rasterized, pro-
                     ducing 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 pro-
                     duced, 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 pro-
                     duced, 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:

     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.

MirOS BSD #10-current  Printed 03.04.2017                       1

GLRENDERMODE(3G)    UNIX Programmer's Manual     GLRENDERMODE(3G)

     See the glSelectBuffer and glFeedbackBuffer reference pages
     for more details concerning selection and feedback opera-
     tion.

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 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 exe-
     cuted between the execution of glBegin and the corresponding
     execution of glEnd.

ASSOCIATED GETS

     glGet with argument GL_RENDER_MODE

SEE ALSO

     glFeedbackBuffer(3G), glInitNames(3G), glLoadName(3G),
     glPassThrough(3G), glPushName(3G), glSelectBuffer(3G)

MirOS BSD #10-current  Printed 03.04.2017                       2

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