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Manual Reference Pages  - GLRENDERMODE (3G)

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glRenderMode - set rasterization mode

CONTENTS

C Specification
Parameters
Description
Notes
Errors
Associated Gets
See Also

GLint glRenderMode( GLenum mode )

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:

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 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.

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

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