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/*
* Copyright (C) 1998 Janne Lf <jlof@mail.student.oulu.fi>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <math.h>
#include <gtk/gtk.h>
#include <gtkgl/gtkglarea.h>
#include <GL/gl.h>
gint init(GtkWidget *widget)
{
/* OpenGL functions can be called only if make_current returns true */
if (gtk_gl_area_make_current(GTK_GL_AREA(widget)))
{
glViewport(0,0, widget->allocation.width, widget->allocation.height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0,100, 100,0, -1,1);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
return TRUE;
}
/* When widget is exposed it's contents are redrawn. */
gint draw(GtkWidget *widget, GdkEventExpose *event)
{
/* Draw only last expose. */
if (event->count > 0)
return TRUE;
/* OpenGL functions can be called only if make_current returns true */
if (gtk_gl_area_make_current(GTK_GL_AREA(widget)))
{
/* Draw simple triangle */
glClearColor(0,0,0,1);
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1,1,1);
glBegin(GL_TRIANGLES);
glVertex2f(10,10);
glVertex2f(10,90);
glVertex2f(90,90);
glEnd();
/* Swap backbuffer to front */
gtk_gl_area_swapbuffers(GTK_GL_AREA(widget));
}
return TRUE;
}
/* When glarea widget size changes, viewport size is set to match the new size */
gint reshape(GtkWidget *widget, GdkEventConfigure *event)
{
/* OpenGL functions can be called only if make_current returns true */
if (gtk_gl_area_make_current(GTK_GL_AREA(widget)))
{
glViewport(0,0, widget->allocation.width, widget->allocation.height);
}
return TRUE;
}
int main(int argc, char **argv)
{
GtkWidget *window,*glarea;
gchar *info_str;
/* Attribute list for gtkglarea widget. Specifies a
list of Boolean attributes and enum/integer
attribute/value pairs. The last attribute must be
GDK_GL_NONE. See glXChooseVisual manpage for further
explanation.
*/
int attrlist[] = {
GDK_GL_RGBA,
GDK_GL_RED_SIZE,1,
GDK_GL_GREEN_SIZE,1,
GDK_GL_BLUE_SIZE,1,
GDK_GL_DOUBLEBUFFER,
GDK_GL_NONE
};
/* initialize gtk */
gtk_init(&argc, &argv);
/* Check if OpenGL is supported. */
if (gdk_gl_query() == FALSE) {
g_print("OpenGL not supported\n");
return 0;
}
/* Create new top level window. */
window = gtk_window_new( GTK_WINDOW_TOPLEVEL);
gtk_window_set_title(GTK_WINDOW(window), "Simple");
gtk_container_set_border_width(GTK_CONTAINER(window), 10);
/* Quit form main if got delete event */
gtk_signal_connect(GTK_OBJECT(window), "delete_event",
GTK_SIGNAL_FUNC(gtk_main_quit), NULL);
/* You should always delete gtk_gl_area widgets before exit or else
GLX contexts are left undeleted, this may cause problems (=core dump)
in some systems.
Destroy method of objects is not automatically called on exit.
You need to manually enable this feature. Do gtk_quit_add_destroy()
for all your top level windows unless you are certain that they get
destroy signal by other means.
*/
gtk_quit_add_destroy(1, GTK_OBJECT(window));
/* Create new OpenGL widget. */
glarea = GTK_WIDGET(gtk_gl_area_new(attrlist));
/* Events for widget must be set before X Window is created */
gtk_widget_set_events(GTK_WIDGET(glarea),
GDK_EXPOSURE_MASK|
GDK_BUTTON_PRESS_MASK);
/* Connect signal handlers */
/* Redraw image when exposed. */
gtk_signal_connect(GTK_OBJECT(glarea), "expose_event",
GTK_SIGNAL_FUNC(draw), NULL);
/* When window is resized viewport needs to be resized also. */
gtk_signal_connect(GTK_OBJECT(glarea), "configure_event",
GTK_SIGNAL_FUNC(reshape), NULL);
/* Do initialization when widget has been realized. */
gtk_signal_connect(GTK_OBJECT(glarea), "realize",
GTK_SIGNAL_FUNC(init), NULL);
/* set minimum size */
gtk_widget_set_usize(GTK_WIDGET(glarea), 100,100);
/* put glarea into window and show it all */
gtk_container_add(GTK_CONTAINER(window),GTK_WIDGET(glarea));
gtk_widget_show(GTK_WIDGET(glarea));
gtk_widget_show(GTK_WIDGET(window));
/* vendor dependent version info string */
info_str = gdk_gl_get_info();
g_print(info_str);
g_free(info_str);
gtk_main();
return 0;
}
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