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/******************************************************************************
* Copyright (C) 1999 Chris Abernethy <chris65536@home.com> *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License *
* as published by the Free Software Foundation; either version 2 *
* of the License, or (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the Free Software *
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, *
* USA. *
* *
******************************************************************************
*
* This is a short, heavily commented demo program designed to help
* get you started using the GtkGLArea widget in your gtk programs.
*
* The program creates a window with a GtkGLArea widget and a quit button.
* Some commonly used callbacks are registered, but nothing is drawn into
* the window.
*
* Please email me with any corrections, additions, or clarifications!
*
* Created 11.14.1999
* Modified 11.14.1999
*
* Compile command:
*
* gcc gtkglarea_demo.c `gtk-config --libs --cflags` -lMesaGL -lgtkgl
*
************/
#include <glib.h> /* For G_OS_WIN32 */
#ifdef G_OS_WIN32
#include <windows.h>
#endif
#include <GL/gl.h>
#include <gtk/gtk.h>
#include <gtkgl/gtkglarea.h>
GtkWidget* create_glarea (void);
gint glarea_button_release (GtkWidget*, GdkEventButton*);
gint glarea_button_press (GtkWidget*, GdkEventButton*);
gint glarea_motion_notify (GtkWidget*, GdkEventMotion*);
gint glarea_draw (GtkWidget*, GdkEventExpose*);
gint glarea_reshape (GtkWidget*, GdkEventConfigure*);
gint glarea_init (GtkWidget*);
gint glarea_destroy (GtkWidget*);
int main (int, char**);
/*****************************************************************************/
/* */
/* Function: create_glarea (void) */
/* */
/* This function performs the necessary operations to construct a GtkGlarea */
/* widget. These operations include creating the widget, setting the size */
/* of the widget, and registering callbacks for the widget. */
/* */
/* This is a good place to add function calls for any GtkGlarea */
/* initialization that you need to do. */
/* */
/*****************************************************************************/
GtkWidget* create_glarea (void) {
GtkWidget* glarea;
/* Choose the attributes that we would like for our visual. */
/* These attributes are passed to glXChooseVisual by the */
/* gdk (see gdk_gl_choose_visual in gdkgl.c from the */
/* GtkGlarea distro). */
/* */
/* */
/* From the glXChooseVisual manpage: */
/* */
/* glXChooseVisual returns a pointer to an XVisualInfo */
/* structure describing the visual that best meets a */
/* minimum specification. */
/* */
/* Check out the manpage for a complete list of attributes */
/* and their descriptions. */
int attrlist[] = {
GDK_GL_RGBA,
GDK_GL_DOUBLEBUFFER,
GDK_GL_DEPTH_SIZE, 1,
GDK_GL_NONE
};
/* First things first! Make sure that OpenGL is supported */
/* before trying to do OpenGL stuff! */
if(gdk_gl_query() == FALSE) {
g_print("OpenGL not supported!\n");
return NULL;
}
/* Now, create the GtkGLArea using the attribute list that */
/* we defined above. */
if ((glarea = gtk_gl_area_new(attrlist)) == NULL) {
g_print("Error creating GtkGLArea!\n");
return NULL;
}
/* Indicate which events we are interested in receiving in */
/* in the window allocated to our glarea widget. */
/* */
/* Check out gdk/gdktypes.h in your include directory for a */
/* complete list of event masks that you can use. */
gtk_widget_set_events(GTK_WIDGET(glarea),
GDK_EXPOSURE_MASK|
GDK_BUTTON_PRESS_MASK|
GDK_BUTTON_RELEASE_MASK|
GDK_POINTER_MOTION_MASK|
GDK_POINTER_MOTION_HINT_MASK);
/* Here we register the callbacks for the specific events */
/* we are interested in handling. Event handling is beyond */
/* the scope of this demo, but a good place to start for */
/* learning about this is the gtk web pages at www.gtk.org */
/* */
/* The following callback registration code registers */
/* callbacks for some of the more common things that you */
/* might want to do with an OpenGL window. */
/* button_release_event - The user has released one of the */
/* mouse buttons in the window. */
g_signal_connect (G_OBJECT(glarea), "button-release-event",
G_CALLBACK(glarea_button_release), NULL);
/* button_press_event - The user has pressed one of the */
/* mouse buttons in the window. */
g_signal_connect (G_OBJECT(glarea), "button-press-event",
G_CALLBACK(glarea_button_press), NULL);
/* motion_notify_event - The mouse is moving in the window. */
g_signal_connect (G_OBJECT(glarea), "motion-notify-event",
G_CALLBACK(glarea_motion_notify), NULL);
/* expose_event - The window was exposed and the contents */
/* need to be redrawn. */
g_signal_connect (G_OBJECT(glarea), "expose-event",
G_CALLBACK(glarea_draw), NULL);
/* configure_event - The window has been resized. You will */
/* probably want to call your reshape */
/* function here. */
g_signal_connect (G_OBJECT(glarea), "configure-event",
G_CALLBACK(glarea_reshape), NULL);
/* realize - The window has been created, this is where you */
/* can hook up your initialization routines. */
g_signal_connect (G_OBJECT(glarea), "realize",
G_CALLBACK(glarea_init), NULL);
/* destroy - The window has received a destroy event, this */
/* is where you should do any cleanup that needs */
/* to happen, such as de-allocating data objects */
/* that you have added to your GtkGLArea. */
g_signal_connect (G_OBJECT(glarea), "destroy",
G_CALLBACK (glarea_destroy), NULL);
gtk_widget_set_size_request(GTK_WIDGET(glarea), 256, 256);
return (glarea);
}
/*****************************************************************************/
/* */
/* Function: glarea_button_release (GtkWidget*, GdkEventButton*) */
/* */
/* This function handles button-release events for the GtkGLArea into which */
/* we are drawing. */
/* */
/*****************************************************************************/
gint glarea_button_release (GtkWidget* widget, GdkEventButton* event) {
int x = event->x;
int y = event->y;
if (event->button == 1) {
/* Mouse button 1 was released */
g_print ("Button 1 release (%d, %d)\n", x, y);
return TRUE;
}
if (event->button == 2) {
/* Mouse button 2 was released */
g_print ("Button 2 release (%d, %d)\n", x, y);
return TRUE;
}
return FALSE;
}
/*****************************************************************************/
/* */
/* Function: glarea_button_press (GtkWidget*, GdkEventButton*) */
/* */
/* This function handles button-press events for the GtkGLArea into which we */
/* are drawing. */
/* */
/*****************************************************************************/
gint glarea_button_press (GtkWidget* widget, GdkEventButton* event) {
int x = event->x;
int y = event->y;
if (event->button == 1) {
/* Mouse button 1 was engaged */
g_print ("Button 1 press (%d, %d)\n", x, y);
return TRUE;
}
if (event->button == 2) {
/* Mouse button 2 was engaged */
g_print ("Button 2 press (%d, %d)\n", x, y);
return TRUE;
}
return FALSE;
}
/*****************************************************************************/
/* */
/* Function: glarea_motion_notify (GtkWidget*, GdkEventMotion*) */
/* */
/* This function handles motion events for the GtkGLArea into which we are */
/* drawing */
/* */
/*****************************************************************************/
gint glarea_motion_notify (GtkWidget* widget, GdkEventMotion* event) {
int x;
int y;
GdkModifierType state;
if (event->is_hint) {
gdk_window_get_pointer(event->window, &x, &y, &state);
} else {
x = event->x;
y = event->y;
state = event->state;
}
if (state & GDK_BUTTON1_MASK) {
/* Mouse button 1 is engaged */
g_print ("Button 1 motion (%d, %d)\n", x, y);
}
if (state & GDK_BUTTON2_MASK) {
/* Mouse button 2 is engaged */
g_print ("Button 2 motion (%d, %d)\n", x, y);
}
return TRUE;
}
/*****************************************************************************/
/* */
/* Function: glarea_draw (GtkWidget*, GdkEventExpose*) */
/* */
/* This is the function that should render your scene to the GtkGLArea. It */
/* can be used as a callback to the 'Expose' event. */
/* */
/*****************************************************************************/
gint glarea_draw (GtkWidget* widget, GdkEventExpose* event) {
/* Draw only on the last expose event. */
if (event->count > 0) {
return(TRUE);
}
g_print ("Expose Event\n");
/* gtk_gl_area_make_current MUST be called before rendering */
/* into the GtkGLArea. */
if (gtk_gl_area_make_current(GTK_GL_AREA(widget))) {
/* Clear the drawing color buffer and depth buffers */
/* before drawing. */
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
/* */
/* Insert your drawing code here. */
/* */
/* Swap the back and front buffers. Using doublebuffers */
/* is definitely recommended! Take a look at the red */
/* book if you don't already have an understanding of */
/* single vs. double buffered windows. */
gtk_gl_area_swap_buffers (GTK_GL_AREA(widget));
}
return (TRUE);
}
/*****************************************************************************/
/* */
/* Function: glarea_reshape (GtkWidget*, GdkEventConfigure*) */
/* */
/* This function performs the operations needed to maintain the viewing area */
/* of the GtkGLArea. This should be called whenever the size of the area */
/* is changed. */
/* */
/*****************************************************************************/
gint glarea_reshape (GtkWidget* widget, GdkEventConfigure* event) {
GtkAllocation allocation;
gtk_widget_get_allocation (widget, &allocation);
int w = allocation.width;
int h = allocation.height;
g_print ("Reshape Event\n");
/* gtk_gl_area_make_current MUST be called before rendering */
/* into the GtkGLArea. */
if (gtk_gl_area_make_current (GTK_GL_AREA(widget))) {
/* This is an example 2D reshape function. Writing reshape */
/* functions is beyond the scope of this demo. Check the */
/* red book or the www.opengl.org for more information on */
/* how to write reshape code to suit your needs. */
glViewport (0, 0, w, h);
glMatrixMode (GL_PROJECTION);
glLoadIdentity ();
glOrtho (-(w>>1), (w>>1), -(h>>1), h>>1, -1, 1);
glMatrixMode (GL_MODELVIEW);
}
return (TRUE);
}
/*****************************************************************************/
/* */
/* Function: glarea_init (GtkWidget*) */
/* */
/* This function is a callback for the realization of the GtkGLArea widtget. */
/* You should do any OpenGL initialization here. */
/* */
/*****************************************************************************/
gint glarea_init (GtkWidget* widget) {
g_print ("Realize Event\n");
/* gtk_gl_area_make_current MUST be called before rendering */
/* into the GtkGLArea. */
if (gtk_gl_area_make_current (GTK_GL_AREA(widget))) {
/* Insert your OpenGL initialization code here */
}
return TRUE;
}
/*****************************************************************************/
/* */
/* Function: glarea_destroy (GtkWidget*) */
/* */
/* This function is a callback for the main GtkGLArea. It deletes should */
/* delete any data structures stored in the GtkGLArea. */
/* */
/*****************************************************************************/
gint glarea_destroy (GtkWidget* widget) {
g_print ("GTK GL Area Destroy Event\n");
/* Insert any required cleanup */
/* code here. */
return TRUE;
}
/*****************************************************************************/
/* */
/* Function: main (int, char**) */
/* */
/* The main function sets up our GUI and calls the functions needed to */
/* create our GtkGLArea. */
/* */
/*****************************************************************************/
int main (int argc, char** argv) {
GtkWidget* window;
GtkWidget* button_quit;
GtkWidget* box_main;
GtkWidget* glarea;
gtk_init (&argc, &argv);
/* Main widget container */
box_main = gtk_vbox_new (FALSE, 10);
/* GTK GL Area */
glarea = create_glarea ();
/* Quit button */
button_quit = gtk_button_new_with_label ("Quit");
g_signal_connect (G_OBJECT(button_quit), "clicked",
G_CALLBACK(gtk_main_quit), NULL);
/* Main window */
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title (GTK_WINDOW(window), "GtkGLArea Demo");
/* destroy this window when exiting from gtk_main() */
gtk_quit_add_destroy (1, GTK_OBJECT(window));
g_signal_connect (G_OBJECT(window), "delete-event",
G_CALLBACK(gtk_main_quit), NULL);
g_signal_connect (G_OBJECT (window), "destroy",
G_CALLBACK(gtk_main_quit), NULL);
gtk_container_set_border_width (GTK_CONTAINER(window), 10);
/* Pack everything into the main box, add the main box to */
/* the top-level window, and 'show' all of the widgets. */
/* The window is 'shown' last so that when the user sees */
/* it, it's contents are already there. Otherwise they */
/* might see each widget come up. */
gtk_box_pack_start (GTK_BOX(box_main), glarea, FALSE, TRUE, 0);
gtk_box_pack_start (GTK_BOX(box_main), button_quit, FALSE, TRUE, 0);
gtk_container_add (GTK_CONTAINER(window), box_main);
gtk_widget_show (glarea);
gtk_widget_show (button_quit);
gtk_widget_show (box_main);
gtk_widget_show (window);
gtk_main ();
return (0);
}
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