glRenderMode — set rasterization mode
Specifies the rasterization mode. Three values are accepted:
GL_FEEDBACK. The initial value is
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:
The number of hit records transferred to the select buffer.
The number of values (not vertices) transferred to the feedback buffer.
GL_INVALID_ENUM is generated if
mode is not one of the three accepted values.
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.
glGet with argument
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.