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.Dd October 12, 2007
.Dt AG_GLVIEW 3
.Os
.ds vT Agar API Reference
.ds oS Agar 1.2
.Sh NAME
.Nm AG_GLView
.Nd low-level OpenGL context widget
.Sh SYNOPSIS
.Bd -literal
#include <agar/core.h>
#include <agar/gui.h>
.Ed
.Sh DESCRIPTION
The
.Nm
widget provides a low-level OpenGL context.
.Pp
If needed, the Agar-SG library can provide higher-level scene rendering
capabilities (see
.Xr SG_View 3 ,
which inherits from
.Nm ) .
.Sh INHERITANCE HIERARCHY
.Xr AG_Object 3 ->
.Xr AG_Widget 3 ->
.Nm .
.Sh INITIALIZATION
.nr nS 1
.Ft "AG_GLView *"
.Fn AG_GLViewNew "AG_Widget *parent" "Uint flags"
.Pp
.Ft void
.Fn AG_GLViewSizeHint "AG_GLView *glv" "int w" "int h"
.Pp
.Ft void
.Fn AG_GLViewDrawFn "AG_GLView *glv" "void (*fn)(AG_Event *)" "const char *args" "..."
.Pp
.Ft void
.Fn AG_GLViewOverlayFn "AG_GLView *glv" "void (*fn)(AG_Event *)" "const char *args" "..."
.Pp
.Ft void
.Fn AG_GLViewScaleFn "AG_GLView *glv" "void (*fn)(AG_Event *)" "const char *args" "..."
.Pp
.Ft void
.Fn AG_GLViewKeydownFn "AG_GLView *glv" "void (*fn)(AG_Event *)" "const char *args" "..."
.Pp
.Ft void
.Fn AG_GLViewKeyupFn "AG_GLView *glv" "void (*fn)(AG_Event *)" "const char *args" "..."
.Pp
.Ft void
.Fn AG_GLViewButtondownFn "AG_GLView *glv" "void (*fn)(AG_Event *)" "const char *args" "..."
.Pp
.Ft void
.Fn AG_GLViewButtonupFn "AG_GLView *glv" "void (*fn)(AG_Event *)" "const char *args" "..."
.Pp
.Ft void
.Fn AG_GLViewMotionFn "AG_GLView *glv" "void (*fn)(AG_Event *)" "const char *args" "..."
.Pp
.nr nS 0
The
.Fn AG_GLViewNew
function allocates, initializes, and attaches a new
.Nm
widget.
There are currently no
.Fa flags
specific to this widget.
.Pp
.Fn AG_GLViewSizeHint
suggests an initial widget size in pixels.
.Pp
The
.Fn AG_GLViewDrawFn
registers a the rendering function (specified in
.Xr AG_Event 3
format).
Prior to invoking this function, the widget will set the
.Xr glViewport 3
to the widget area, save the current OpenGL matrices and load the
widget-specific matrices.
.Pp
.Fn AG_GLViewOverlayFn
registers a function that will be invoked after rendering, after the
GUI matrices and viewport have been restored.
It is typically used to draw text or controls independently of the
.Nm ' s
projection and viewing matrices.
.Pp
.Fn AG_GLViewScaleFn
registers a function to invoke whenever the widget is resized.
.Pp
.Fn AG_GLViewKeydownFn ,
.Fn AG_GLViewKeyupFn ,
.Fn AG_GLViewButtondownFn ,
.Fn AG_GLViewButtonupFn
and
.Fn AG_GLViewMotionFn
register general event handler functions that will be forwarded
.Sq window-keydown ,
.Sq window-keyup ,
.Sq window-mousebuttondown ,
.Sq window-mousebuttonup
and
.Sq window-mousemotion
events, respectively.
.Sh BINDINGS
The
.Nm
widget does not provide any binding.
.Sh EVENTS
The
.Nm
widget reacts to the following events:
.Pp
.Bl -tag -compact -width "widget-moved "
.It widget-moved
Projection matrix is recomputed and the
.Va scale
operation is invoked.
.El
.Pp
The
.Nm
widget does not generate any event.
.Sh STRUCTURE DATA
For the
.Ft AG_GLView
object:
.Pp
.Bl -tag -width "float mProjection[16] "
.It Ft float mProjection[16]
Projection matrix (4x4, column-major) to automatically load every time the
.Nm
is drawn.
Defaults to identity.
.It Ft float mModelview[16]
Modelview matrix (4x4, column-major) to automatically load every time the
.Nm
is drawn.
Defaults to identity.
.It Ft float mTexture[16]
Texture matrix (4x4, column-major) to automatically load every time the
.Nm
is drawn.
Defaults to identity.
.El
.Sh EXAMPLES
See the
.Pa glview
demo in the Agar
.Pa demos
directory.
.Sh SEE ALSO
.Xr AG_Intro 3 ,
.Xr AG_Widget 3 ,
.Xr AG_Window 3 ,
.Xr SG 3 ,
.Xr SG_View 3
.Sh HISTORY
The
.Nm
widget first appeared in Agar 1.2.