#include <config.h>
#include <gtk/gtk.h>
#include <gtk/gtkgl.h>
#include <gdk/gdkkeysyms.h>
#include <GL/gl.h>
#include <math.h>

float boxv[][3] = {
	{ -0.5, -0.5, -0.5 },
	{  0.5, -0.5, -0.5 },
	{  0.5,  0.5, -0.5 },
	{ -0.5,  0.5, -0.5 },
	{ -0.5, -0.5,  0.5 },
	{  0.5, -0.5,  0.5 },
	{  0.5,  0.5,  0.5 },
	{ -0.5,  0.5,  0.5 }
};
#define ALPHA 0.5

static float ang = 30.;

gboolean expose (GtkWidget *da, GdkEventExpose *event, gpointer user_data)
{
	GdkGLContext *glcontext = gtk_widget_get_gl_context (da);
	GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable (da);

	// g_print (" :: expose\n");

	if (!gdk_gl_drawable_gl_begin (gldrawable, glcontext))
	{
		g_assert_not_reached ();
	}

	/* draw in here */
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glPushMatrix();
	
	glRotatef (ang, 1, 0, 1);

	glShadeModel(GL_FLAT);

	glBegin (GL_LINES);
	glColor3f (1., 0., 0.);
	glVertex3f (0., 0., 0.);
	glVertex3f (1., 0., 0.);
	glEnd ();
	
	glBegin (GL_LINES);
	glColor3f (0., 1., 0.);
	glVertex3f (0., 0., 0.);
	glVertex3f (0., 1., 0.);
	glEnd ();
	
	glBegin (GL_LINES);
	glColor3f (0., 0., 1.);
	glVertex3f (0., 0., 0.);
	glVertex3f (0., 0., 1.);
	glEnd ();

	glBegin(GL_LINES);
	glColor3f (1., 1., 1.);
	glVertex3fv(boxv[0]);
	glVertex3fv(boxv[1]);
	
	glVertex3fv(boxv[1]);
	glVertex3fv(boxv[2]);
	
	glVertex3fv(boxv[2]);
	glVertex3fv(boxv[3]);
	
	glVertex3fv(boxv[3]);
	glVertex3fv(boxv[0]);
	
	glVertex3fv(boxv[4]);
	glVertex3fv(boxv[5]);
	
	glVertex3fv(boxv[5]);
	glVertex3fv(boxv[6]);
	
	glVertex3fv(boxv[6]);
	glVertex3fv(boxv[7]);
	
	glVertex3fv(boxv[7]);
	glVertex3fv(boxv[4]);
	
	glVertex3fv(boxv[0]);
	glVertex3fv(boxv[4]);
	
	glVertex3fv(boxv[1]);
	glVertex3fv(boxv[5]);
	
	glVertex3fv(boxv[2]);
	glVertex3fv(boxv[6]);
	
	glVertex3fv(boxv[3]);
	glVertex3fv(boxv[7]);
	glEnd();

	glPopMatrix ();

	if (gdk_gl_drawable_is_double_buffered (gldrawable))
		gdk_gl_drawable_swap_buffers (gldrawable);

	else
		glFlush ();

	gdk_gl_drawable_gl_end (gldrawable);

	return TRUE;
}

gboolean configure(GtkWidget *da, GdkEventConfigure *event, gpointer user_data)
{
	GdkGLContext *glcontext = gtk_widget_get_gl_context (da);
	GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable (da);

	if (!gdk_gl_drawable_gl_begin (gldrawable, glcontext))
	{
		g_assert_not_reached ();
	}

	glLoadIdentity();
	glViewport (0, 0, da->allocation.width, da->allocation.height);
	glOrtho (-10,10,-10,10,-20050,10000);
	glEnable (GL_BLEND);
	glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

	glScalef (10., 10., 10.);
	
	gdk_gl_drawable_gl_end (gldrawable);

	return TRUE;
}

gboolean rotate (gpointer user_data)
{
	GtkWidget *da = GTK_WIDGET (user_data);

	ang++;

	gdk_window_invalidate_rect (da->window, &da->allocation, FALSE);
	gdk_window_process_updates (da->window, FALSE);

	return TRUE;
}

gboolean cube_init(GtkDrawingArea *drawing)
{
	g_signal_connect(drawing, "configure-event", G_CALLBACK(configure), NULL);
	g_signal_connect(drawing, "expose-event",    G_CALLBACK(expose),    NULL);
	g_timeout_add(1000/60, rotate, drawing);
}