Gl.RenderMode (gb.opengl)
Static Function RenderMode ( Mode As Integer ) As Array
Set rasterization 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
Gl.RenderMode 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 Gl.SelectBuffer) 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 Gl.FeedbackBuffer) before feedback mode
is entered.
The return value of
Gl.RenderMode is determined by the render mode at the time
Gl.RenderMode 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 Gl.SelectBuffer and Gl.FeedbackBuffer reference pages for
more details concerning selection and feedback operation.
Notes
If an error is generated,
Gl.RenderMode 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 Gl.SelectBuffer is called
while the render mode is Gl.SELECT,
or if
Gl.RenderMode is called with argument Gl.SELECT before
Gl.SelectBuffer is called at least once.
Gl.INVALID_OPERATION is generated if
Gl.FeedbackBuffer is called
while the render mode is
Gl.FEEDBACK,
or if
Gl.RenderMode is called with argument Gl.FEEDBACK before
Gl.FeedbackBuffer is called at least once.
Gl.INVALID_OPERATION is generated if
Gl.RenderMode
is executed between the execution of Gl.Begin
and the corresponding execution of Gl.End.
Associated Gets
Gl.Get with argument Gl.RENDER_MODE
See also
Gl.PushName,
Gl.SelectBuffer