I have found the way. Here is my code. Any idea where I can post it as a
tutorial?
#include <stdlib.h>
#include <glib.h>
#include <gdk/gdk.h>
#include <gdk/gdkgl.h>
#include <GL/gl.h>
GdkGLWindow *glwin = NULL;
GdkGLContext *glcontext = NULL;
GMainLoop *mainloop;
static void event_func(GdkEvent *ev, gpointer data) {
printf("event func\n");
switch(ev->type) {
case GDK_MAP:
break;
case GDK_DELETE:
g_main_loop_quit(mainloop);
break;
case GDK_KEY_PRESS:
printf("key pressed\n");
break;
case GDK_EXPOSE:
printf("got expose\n");
break;
case GDK_CONFIGURE:
if(gdk_gl_drawable_gl_begin(gdk_window_get_gl_drawable(ev->configure.window),
glcontext)) {
glViewport(0, 0, ev->configure.width,
ev->configure.height);
if(gdk_gl_drawable_is_double_buffered(gdk_window_get_gl_drawable(ev->configure.window)))
{
gdk_gl_drawable_swap_buffers(gdk_window_get_gl_drawable(ev->configure.window));
} else
glFlush();
gdk_gl_drawable_gl_end(gdk_window_get_gl_drawable(ev->configure.window));
}
break;
}
if(gdk_gl_drawable_gl_begin(gdk_window_get_gl_drawable(ev->any.window),
glcontext)) {
glClearColor(1.0, .5, .2, 1.0);
glClear(GL_COLOR_BUFFER_BIT);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, 800, 600, 0, -1, 1);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glBegin(GL_QUADS);
glVertex2i(100, 100);
glVertex2i(400, 100);
glVertex2i(400, 500);
glVertex2i(100, 500);
glEnd();
if(gdk_gl_drawable_is_double_buffered(gdk_window_get_gl_drawable(ev->any.window)))
{
gdk_gl_drawable_swap_buffers(gdk_window_get_gl_drawable(ev->any.window));
} else
glFlush();
gdk_gl_drawable_gl_end(gdk_window_get_gl_drawable(ev->any.window));
}
}
int main(int argc, char **argv) {
gdk_init(&argc, &argv);
gdk_gl_init(&argc, &argv);
int config_attributes[] = {
GDK_GL_DOUBLEBUFFER,
GDK_GL_RGBA,
GDK_GL_RED_SIZE, 1,
GDK_GL_GREEN_SIZE, 1,
GDK_GL_BLUE_SIZE, 1,
GDK_GL_DEPTH_SIZE, 12,
GDK_GL_ATTRIB_LIST_NONE
};
GdkGLConfig *glc = gdk_gl_config_new(config_attributes);
GdkWindowAttr attr;
attr.title = argv[0];
attr.event_mask = GDK_KEY_PRESS_MASK | GDK_STRUCTURE_MASK |
GDK_EXPOSURE_MASK;
attr.window_type = GDK_WINDOW_TOPLEVEL;
attr.wclass = GDK_INPUT_OUTPUT;
attr.width = 800;
attr.height = 600;
GdkWindow *win = gdk_window_new(NULL, &attr, 0);
gdk_window_show(win);
glwin = gdk_window_set_gl_capability(win, glc, NULL);
glcontext = gdk_gl_context_new(GDK_GL_DRAWABLE(glwin), NULL, true,
GDK_GL_RGBA_TYPE);
gdk_event_handler_set(event_func, NULL, NULL); // this is used by GTK+
internally. We just use it for ourselves here
mainloop = g_main_loop_new(g_main_context_default(), FALSE);
g_main_loop_run(mainloop);
gdk_gl_window_destroy(glwin);
gdk_window_destroy(win);
return 0;
}
On Thu, Jul 23, 2009 at 8:07 AM, Emmanuel Rodriguez <
emmanuel.rodrig...@gmail.com> wrote:
>
>
> On Thu, Jul 23, 2009 at 5:33 AM, Mihai Draghicioiu <
> mihai.draghici...@gmail.com> wrote:
>
>> Hi all! I'm making an OpenGL application based on GDK + GtkGLArea. My code
>> so far works, but it has two issues:
>
> Do you really need to have your application based on GDK? Can't you use GTK
> instead?
> By using GTK you can simply connect to the wanted signals and start a main
> loop. This is going to be easier.
>
> The tar.gz of gtkglext has an examples directory and you should be able to
> start from one of their sample programs.
>
> You should consider modifying your code to use GTK instead of GDK:
>
> #include <stdlib.h>
> #include <gtk/gtk.h>
> #include <gtk/gtkgl.h>
> #include <GL/gl.h>
>
>
> static void
> realize (GtkWidget *widget,
> gpointer data)
> {
> GdkGLContext *glcontext = gtk_widget_get_gl_context (widget);
> GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable (widget);
>
> if (!gdk_gl_drawable_gl_begin(gldrawable, glcontext)) {
> return;
> }
>
> glClearColor(1.0, .5, .2, 1.0);
> glClear(GL_COLOR_BUFFER_BIT);
> glMatrixMode(GL_PROJECTION);
> glLoadIdentity();
> glOrtho(0, widget->allocation.width, widget->allocation.height, 0, -1,
> 1);
> glMatrixMode(GL_MODELVIEW);
> glLoadIdentity();
>
> glColor3f(0.0, 1.0, 0.0);
> glBegin(GL_QUADS);
> glVertex2i(100, 100);
> glVertex2i(400, 100);
> glVertex2i(400, 500);
> glVertex2i(100, 500);
> glEnd();
>
> /* swap backbuffer to front */
> if (gdk_gl_drawable_is_double_buffered(gldrawable))
> gdk_gl_drawable_swap_buffers(gldrawable);
> else
> glFlush();
>
> gdk_gl_drawable_gl_end (gldrawable);
> }
>
> static gboolean
> configure_event (GtkWidget *widget,
> GdkEventConfigure *event,
> gpointer data)
> {
> GdkGLContext *glcontext = gtk_widget_get_gl_context (widget);
> GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable (widget);
>
> /*** OpenGL BEGIN ***/
> if (!gdk_gl_drawable_gl_begin (gldrawable, glcontext))
> return FALSE;
>
> glViewport (0, 0,
> widget->allocation.width, widget->allocation.height);
>
> gdk_gl_drawable_gl_end (gldrawable);
> /*** OpenGL END ***/
>
> return TRUE;
> }
>
> static gboolean
> expose_event (GtkWidget *widget,
> GdkEventExpose *event,
> gpointer data)
> {
> GdkGLContext *glcontext = gtk_widget_get_gl_context (widget);
> GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable (widget);
>
> /*** OpenGL BEGIN ***/
> if (!gdk_gl_drawable_gl_begin (gldrawable, glcontext))
> return FALSE;
>
> glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
>
> glCallList (1);
>
> if (gdk_gl_drawable_is_double_buffered (gldrawable))
> gdk_gl_drawable_swap_buffers (gldrawable);
> else
> glFlush ();
>
> gdk_gl_drawable_gl_end (gldrawable);
> /*** OpenGL END ***/
>
> return TRUE;
> }
>
>
> int main(int argc, char **argv) {
> gtk_init(&argc, &argv);
> gtk_gl_init(&argc, &argv);
>
> int config_attributes[] = {
> GDK_GL_DOUBLEBUFFER,
> GDK_GL_RGBA,
> GDK_GL_RED_SIZE, 1,
> GDK_GL_GREEN_SIZE, 1,
> GDK_GL_BLUE_SIZE, 1,
> GDK_GL_DEPTH_SIZE, 12,
> GDK_GL_ATTRIB_LIST_NONE
> };
> GdkGLConfig *glconfig = gdk_gl_config_new(config_attributes);
>
>
> GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
> gtk_window_set_default_size(GTK_WINDOW(window), 800, 600);
> g_signal_connect (G_OBJECT (window), "delete_event", G_CALLBACK
> (gtk_main_quit), NULL);
>
> // Get automatically redrawn if any of their children changed allocation
> gtk_container_set_reallocate_redraws (GTK_CONTAINER (window), TRUE);
>
>
> // The widget where the OpenGL drawing will be done
> GtkWidget *drawing_area = gtk_drawing_area_new ();
> gtk_widget_set_size_request (drawing_area, 200, 200);
> gtk_widget_set_gl_capability(drawing_area, glconfig, NULL, TRUE,
> GDK_GL_RGBA_TYPE);
> gtk_widget_add_events(GTK_WIDGET(drawing_area), GDK_CONFIGURE);
> gtk_widget_add_events(GTK_WIDGET(drawing_area), GDK_KEY_PRESS_MASK);
> gtk_widget_add_events(GTK_WIDGET(drawing_area), GDK_STRUCTURE_MASK);
> gtk_widget_add_events(GTK_WIDGET(drawing_area), GDK_EXPOSURE_MASK);
>
>
> g_signal_connect_after (G_OBJECT (drawing_area), "realize", G_CALLBACK
> (realize), NULL);
> g_signal_connect (G_OBJECT (drawing_area), "configure_event", G_CALLBACK
> (configure_event), NULL);
> g_signal_connect (G_OBJECT (drawing_area), "expose_event", G_CALLBACK
> (expose_event), NULL);
>
>
> gtk_container_add (GTK_CONTAINER (window), drawing_area);
> gtk_widget_show_all(window);
>
> gtk_main();
>
> return 0;
> }
>
>
> This is a merge of your code and the example simple.c provided by
> gtkglext.tar.gz. Your current drawing method doesn't work but I'm not that
> good with OpenGL. Although if I substitue your drawing by the one of
> simple.c it works. I'm sure that you will be able to figure this bit out for
> me :)
>
> --
> Emmanuel Rodriguez
>
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