{ 3-D gear wheels. This program is in the public domain.
Brian Paul
Conversion to GLUT by Mark J. Kilgard
Conversion to GtkGLExt by Naofumi Yasufuku
Conversion to Pascal binding of GtkGLExt by Michalis Kamburelis
}
{$mode delphi}
uses Glib2, Gtk2, Gdk2, GdkGLExt, GtkGLExt, gl;
{*
* Draw a gear wheel. You'll probably want to call this function when
* building a display list since we do a lot of trig here.
*
* Input: inner_radius - radius of hole at center
* outer_radius - radius at center of teeth
* width - width of gear
* teeth - number of teeth
* tooth_depth - depth of tooth
*}
procedure gear(
inner_radius, outer_radius, width: GLfloat;
teeth: GLint;
tooth_depth: GLfloat);
var
i: GLint;
r0, r1, r2: GLfloat;
angle, da: GLfloat;
u, v, len: GLfloat;
begin
r0 := inner_radius;
r1 := outer_radius - tooth_depth / 2.0;
r2 := outer_radius + tooth_depth / 2.0;
da := 2.0 * Pi / teeth / 4.0;
glShadeModel(GL_FLAT);
glNormal3f(0.0, 0.0, 1.0);
{* draw front face *}
glBegin(GL_QUAD_STRIP);
for i := 0 to teeth do
begin
angle := i * 2.0 * Pi / teeth;
glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
if i < teeth then
begin
glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
end;
end;
glEnd();
{* draw front sides of teeth *}
glBegin(GL_QUADS);
da := 2.0 * Pi / teeth / 4.0;
for i := 0 to teeth - 1 do
begin
angle := i * 2.0 * Pi / teeth;
glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
end;
glEnd();
glNormal3f(0.0, 0.0, -1.0);
{* draw back face *}
glBegin(GL_QUAD_STRIP);
for i := 0 to teeth do
begin
angle := i * 2.0 * Pi / teeth;
glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
if i < teeth then
begin
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
end;
end;
glEnd();
{* draw back sides of teeth *}
glBegin(GL_QUADS);
da := 2.0 * Pi / teeth / 4.0;
for i := 0 to teeth - 1 do
begin
angle := i * 2.0 * Pi / teeth;
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
end;
glEnd();
{* draw outward faces of teeth *}
glBegin(GL_QUAD_STRIP);
for i := 0 to teeth - 1 do
begin
angle := i * 2.0 * Pi / teeth;
glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
u := r2 * cos(angle + da) - r1 * cos(angle);
v := r2 * sin(angle + da) - r1 * sin(angle);
len := sqrt(u * u + v * v);
u := u / len;
v := v / len;
glNormal3f(v, -u, 0.0);
glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
glNormal3f(cos(angle), sin(angle), 0.0);
glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
u := r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
v := r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
glNormal3f(v, -u, 0.0);
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
glNormal3f(cos(angle), sin(angle), 0.0);
end;
glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);
glEnd();
glShadeModel(GL_SMOOTH);
{* draw inside radius cylinder *}
glBegin(GL_QUAD_STRIP);
for i := 0 to teeth do
begin
angle := i * 2.0 * Pi / teeth;
glNormal3f(-cos(angle), -sin(angle), 0.0);
glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
end;
glEnd();
end;
var
view_rotx: GLfloat = 20.0;
view_roty: GLfloat = 30.0;
view_rotz: GLfloat = 0.0;
gear1, gear2, gear3: GLint;
angle: GLfloat = 0.0;
timer: PGTimer = nil;
frames: gint = 0;
is_sync: boolean = true;
function draw(
widget: PGtkWidget;
event: PGdkEventExpose;
data: gpointer): gboolean; cdecl;
var
seconds: gdouble;
fps: gdouble;
glcontext: PGdkGLContext;
gldrawable: PGdkGLDrawable;
begin
glcontext := gtk_widget_get_gl_context (widget);
gldrawable := gtk_widget_get_gl_drawable (widget);
{*** OpenGL BEGIN ***}
if not gdk_gl_drawable_gl_begin (gldrawable, glcontext) then
Exit(false);
glClear (GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);
glPushMatrix ();
glRotatef (view_rotx, 1.0, 0.0, 0.0);
glRotatef (view_roty, 0.0, 1.0, 0.0);
glRotatef (view_rotz, 0.0, 0.0, 1.0);
glPushMatrix ();
glTranslatef (-3.0, -2.0, 0.0);
glRotatef (angle, 0.0, 0.0, 1.0);
glCallList (gear1);
glPopMatrix ();
glPushMatrix ();
glTranslatef (3.1, -2.0, 0.0);
glRotatef (-2.0 * angle - 9.0, 0.0, 0.0, 1.0);
glCallList (gear2);
glPopMatrix ();
glPushMatrix ();
glTranslatef (-3.1, 4.2, 0.0);
glRotatef (-2.0 * angle - 25.0, 0.0, 0.0, 1.0);
glCallList (gear3);
glPopMatrix ();
glPopMatrix ();
if gdk_gl_drawable_is_double_buffered (gldrawable) then
gdk_gl_drawable_swap_buffers (gldrawable) else
glFlush ();
gdk_gl_drawable_gl_end (gldrawable);
{*** OpenGL END ***}
Inc(frames);
seconds := g_timer_elapsed (timer, NULL);
if seconds >= 5.0 then
begin
fps := frames / seconds;
g_print ('%d frames in %6.3f seconds = %6.3f FPS' + LineEnding, [frames, seconds, fps]);
g_timer_reset (timer);
frames := 0;
end;
Result := true;
end;
{* new window size or exposure *}
function reshape (
widget: PGtkWidget;
event: PGdkEventConfigure;
data: gpointer): gboolean; cdecl;
var
glcontext: PGdkGLContext;
gldrawable: PGdkGLDrawable;
h: GLfloat;
begin
glcontext := gtk_widget_get_gl_context (widget);
gldrawable := gtk_widget_get_gl_drawable (widget);
h := widget.allocation.height / widget.allocation.width;
{*** OpenGL BEGIN ***}
if not gdk_gl_drawable_gl_begin (gldrawable, glcontext) then
Exit(false);
glViewport (0, 0, widget.allocation.width, widget.allocation.height);
glMatrixMode (GL_PROJECTION);
glLoadIdentity ();
glFrustum (-1.0, 1.0, -h, h, 5.0, 60.0);
glMatrixMode (GL_MODELVIEW);
glLoadIdentity ();
glTranslatef (0.0, 0.0, -40.0);
gdk_gl_drawable_gl_end (gldrawable);
{*** OpenGL END ***}
Result := true;
end;
procedure init(
widget: PGtkWidget;
data: gpointer); cdecl;
const
pos: array[0..3] of GLfloat = (5.0, 5.0, 10.0, 0.0);
red: array[0..3] of GLfloat = (0.8, 0.1, 0.0, 1.0);
green: array[0..3] of GLfloat = (0.0, 0.8, 0.2, 1.0);
blue: array[0..3] of GLfloat = (0.2, 0.2, 1.0, 1.0);
var
glcontext: PGdkGLContext;
gldrawable: PGdkGLDrawable;
begin
glcontext := gtk_widget_get_gl_context (widget);
gldrawable := gtk_widget_get_gl_drawable (widget);
{*** OpenGL BEGIN ***}
if not gdk_gl_drawable_gl_begin (gldrawable, glcontext) then
Exit;
glLightfv (GL_LIGHT0, GL_POSITION, pos);
glEnable (GL_CULL_FACE);
glEnable (GL_LIGHTING);
glEnable (GL_LIGHT0);
glEnable (GL_DEPTH_TEST);
{* make the gears *}
gear1 := glGenLists (1);
glNewList (gear1, GL_COMPILE);
glMaterialfv (GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
gear (1.0, 4.0, 1.0, 20, 0.7);
glEndList ();
gear2 := glGenLists (1);
glNewList (gear2, GL_COMPILE);
glMaterialfv (GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
gear (0.5, 2.0, 2.0, 10, 0.7);
glEndList ();
gear3 := glGenLists (1);
glNewList (gear3, GL_COMPILE);
glMaterialfv (GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
gear (1.3, 2.0, 0.5, 10, 0.7);
glEndList ();
glEnable (GL_NORMALIZE);
g_print (LineEnding);
g_print ('GL_RENDERER = %s' + LineEnding, [glGetString (GL_RENDERER)]);
g_print ('GL_VERSION = %s' + LineEnding, [glGetString (GL_VERSION)]);
g_print ('GL_VENDOR = %s' + LineEnding, [glGetString (GL_VENDOR)]);
g_print ('GL_EXTENSIONS = %s' + LineEnding, [glGetString (GL_EXTENSIONS)]);
g_print (LineEnding);
gdk_gl_drawable_gl_end (gldrawable);
{*** OpenGL END ***}
{* create timer *}
if timer = nil then
timer := g_timer_new ();
g_timer_start (timer);
end;
function idle (widget: PGtkWidget): gboolean; cdecl;
begin
angle := angle + 2.0;
{* Invalidate the whole window. *}
gdk_window_invalidate_rect (widget.window, @widget.allocation, false);
{* Update synchronously (fast). *}
if is_sync then
gdk_window_process_updates (widget.window, false);
Result := true;
end;
var
idle_id: guint = 0;
procedure idle_add (widget: PGtkWidget); cdecl;
begin
if idle_id = 0 then
begin
idle_id := g_idle_add_full (GDK_PRIORITY_REDRAW,
TGSourceFunc(@idle),
widget,
NULL);
end;
end;
procedure idle_remove (widget: PGtkWidget); cdecl;
begin
if idle_id <> 0 then
begin
g_source_remove (idle_id);
idle_id := 0;
end;
end;
function map (
widget: PGtkWidget;
event: PGdkEventAny;
data: gpointer): gboolean; cdecl;
begin
idle_add (widget);
Result := true;
end;
function unmap (
widget: PGtkWidget;
event: PGdkEventAny;
data: gpointer): gboolean; cdecl;
begin
idle_remove (widget);
Result := true;
end;
function visible (
widget: PGtkWidget;
event: PGdkEventVisibility;
data: gpointer): gboolean; cdecl;
begin
if event.state = GDK_VISIBILITY_FULLY_OBSCURED then
idle_remove (widget) else
idle_add (widget);
Result := true;
end;
{* change view angle, exit upon ESC *}
function key (
widget: PGtkWidget;
event: PGdkEventKey;
data: gpointer): gboolean; cdecl;
begin
case event.keyval of
GDK_KEY_z : view_rotz := view_rotz + 5.0;
GDK_KEY_Capital_Z : view_rotz := view_rotz - 5.0;
GDK_KEY_Up : view_roty := view_roty + 5.0;
GDK_KEY_Down : view_roty := view_roty - 5.0;
GDK_KEY_Left : view_rotx := view_rotx + 5.0;
GDK_KEY_Right : view_rotx := view_rotx - 5.0;
GDK_KEY_Escape : gtk_main_quit ();
else Exit(false);
end;
gdk_window_invalidate_rect (widget.window, @widget.allocation, FALSE);
Result := true;
end;
var
glconfig: PGdkGLConfig;
window: PGtkWidget;
vbox: PGtkWidget;
drawing_area: PGtkWidget;
button: PGtkWidget;
i: Integer;
begin
{*
* Init GTK.
*}
gtk_init (@argc, @argv);
{*
* Init GtkGLExt.
*}
gtk_gl_init (@argc, @argv);
{*
* Command line options.
*}
for i := 1 to ParamCount do
if ParamStr(i) = '--async' then
is_sync := FALSE;
{*
* Configure OpenGL-capable visual.
*}
{* Try double-buffered visual *}
glconfig := gdk_gl_config_new_by_mode (GDK_GL_MODE_RGB or
GDK_GL_MODE_DEPTH or
GDK_GL_MODE_DOUBLE);
if glconfig = nil then
begin
g_print ('*** Cannot find the double-buffered visual.' +LineEnding);
g_print ('*** Trying single-buffered visual.' +LineEnding);
{* Try single-buffered visual *}
glconfig := gdk_gl_config_new_by_mode (GDK_GL_MODE_RGB or
GDK_GL_MODE_DEPTH);
if glconfig = nil then
begin
g_print ('*** No appropriate OpenGL-capable visual found.' +LineEnding);
Halt(1);
end;
end;
{*
* Top-level window.
*}
window := gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title (GTK_WINDOW (window), 'gears');
{* Get automatically redrawn if any of their children changed allocation. *}
gtk_container_set_reallocate_redraws (GTK_CONTAINER (window), TRUE);
g_signal_connect (G_OBJECT (window), 'delete_event',
G_CALLBACK (@gtk_main_quit), NULL);
{*
* VBox.
*}
vbox := gtk_vbox_new (FALSE, 0);
gtk_container_add (GTK_CONTAINER (window), vbox);
gtk_widget_show (vbox);
{*
* Drawing area for drawing OpenGL scene.
*}
drawing_area := gtk_drawing_area_new ();
gtk_widget_set_size_request (drawing_area, 300, 300);
{* Set OpenGL-capability to the widget. *}
gtk_widget_set_gl_capability (drawing_area,
glconfig,
NULL,
TRUE,
GDK_GL_RGBA_TYPE);
gtk_widget_add_events (drawing_area,
GDK_VISIBILITY_NOTIFY_MASK);
g_signal_connect_after (G_OBJECT (drawing_area), 'realize',
G_CALLBACK (@init), NULL);
g_signal_connect (G_OBJECT (drawing_area), 'configure_event',
G_CALLBACK (@reshape), NULL);
g_signal_connect (G_OBJECT (drawing_area), 'expose_event',
G_CALLBACK (@draw), NULL);
g_signal_connect (G_OBJECT (drawing_area), 'map_event',
G_CALLBACK (@map), NULL);
g_signal_connect (G_OBJECT (drawing_area), 'unmap_event',
G_CALLBACK (@unmap), NULL);
g_signal_connect (G_OBJECT (drawing_area), 'visibility_notify_event',
G_CALLBACK (@visible), NULL);
g_signal_connect_swapped (G_OBJECT (window), 'key_press_event',
G_CALLBACK (@key), drawing_area);
gtk_box_pack_start (GTK_BOX (vbox), drawing_area, TRUE, TRUE, 0);
gtk_widget_show (drawing_area);
{*
* Simple quit button.
*}
button := gtk_button_new_with_label ('Quit');
g_signal_connect (G_OBJECT (button), 'clicked',
G_CALLBACK (@gtk_main_quit), NULL);
gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);
gtk_widget_show (button);
{*
* Show window.
*}
gtk_widget_show (window);
{*
* Main loop.
*}
gtk_main ();
end.
