- Method glRenderMode
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.
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.
glFeedbackBufferreference pages for more details concerning selection and feedback operation.
GL_INVALID_ENUM is generated if mode is not one of the three accepted values.
GL_INVALID_OPERATION is generated if
glFeedbackBufferis called while the render mode is GL_FEEDBACK, or if glRenderMode is called with argument GL_FEEDBACK before
glFeedbackBufferis called at least once.