/* $Id: shape.c,v 1.1 1999/08/19 00:55:43 jtg Exp $ */
/*
* Example of using the X "shape" extension with OpenGL: render a spinning
* cube inside of a non-rectangular window.
*
* Press ESC to exit. Press up/down to change window shape.
*
* To compile add "shape" to the PROGS list in Makefile.
*
* Brian Paul
* June 16, 1997
*
* This program is in the public domain.
*/
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/keysym.h>
#include <X11/extensions/shape.h>
#include <GL/glx.h>
#ifndef PI
#define PI 3.1415926
#endif
static int Width=500, Height=500;
static float Xangle = 0.0, Yangle = 0.0;
static int Redraw = 0;
static int Sides = 5;
static int MinSides = 3;
static int MaxSides = 20;
/*
* Draw the OpenGL stuff and do a SwapBuffers.
*/
static void display(Display *dpy, Window win)
{
float scale = 1.7;
glClear(GL_COLOR_BUFFER_BIT);
glPushMatrix();
glScalef(scale, scale, scale);
glRotatef(Xangle, 1.0, 0.0, 0.0);
glRotatef(Yangle, 0.0, 1.0, 0.0);
glColor3f(1.0, 1.0, 1.0);
glBegin(GL_LINE_LOOP);
glVertex3f(-1.0, -1.0, -1.0);
glVertex3f( 1.0, -1.0, -1.0);
glVertex3f( 1.0, 1.0, -1.0);
glVertex3f(-1.0, 1.0, -1.0);
glEnd();
glBegin(GL_LINE_LOOP);
glVertex3f(-1.0, -1.0, 1.0);
glVertex3f( 1.0, -1.0, 1.0);
glVertex3f( 1.0, 1.0, 1.0);
glVertex3f(-1.0, 1.0, 1.0);
glEnd();
glBegin(GL_LINES);
glVertex3f(-1.0, -1.0, -1.0); glVertex3f(-1.0, -1.0, 1.0);
glVertex3f( 1.0, -1.0, -1.0); glVertex3f( 1.0, -1.0, 1.0);
glVertex3f( 1.0, 1.0, -1.0); glVertex3f( 1.0, 1.0, 1.0);
glVertex3f(-1.0, 1.0, -1.0); glVertex3f(-1.0, 1.0, 1.0);
glEnd();
glPopMatrix();
glXSwapBuffers(dpy, win);
}
/*
* Called when no events are pending.
*/
static void idle(void)
{
Xangle += 2.0;
Yangle += 3.3;
Redraw = 1;
}
/*
* This is called when we have to recompute the window shape bitmask.
* We just generate an n-sided regular polygon here but any other shape
* would be possible.
*/
static void make_shape_mask(Display *dpy, Window win, int width, int height,
int sides)
{
Pixmap shapeMask;
XGCValues xgcv;
GC gc;
/* allocate 1-bit deep pixmap and a GC */
shapeMask = XCreatePixmap(dpy, win, width, height, 1);
gc = XCreateGC(dpy, shapeMask, 0, &xgcv);
/* clear shapeMask to zeros */
XSetForeground(dpy, gc, 0);
XFillRectangle(dpy, shapeMask, gc, 0, 0, width, height);
/* draw mask */
XSetForeground(dpy, gc, 1);
{
int cx = width / 2;
int cy = height / 2;
float angle = 0.0;
float step = 2.0 * PI / sides;
float radius = width / 2;
int i;
XPoint points[100];
for (i=0;i<sides;i++) {
int x = cx + radius * sin(angle);
int y = cy - radius * cos(angle);
points[i].x = x;
points[i].y = y;
angle += step;
}
XFillPolygon(dpy, shapeMask, gc, points, sides, Convex, CoordModeOrigin);
}
/* This is the only SHAPE extension call- simple! */
XShapeCombineMask(dpy, win, ShapeBounding, 0, 0, shapeMask, ShapeSet);
XFreeGC(dpy, gc);
XFreePixmap(dpy, shapeMask);
}
/*
* Called when window is resized. Do OpenGL viewport and projection stuff.
*/
static void reshape(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1.0, 1.0, -1.0, 1.0, 3.0, 20.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0, 0.0, -10.0);
}
/*
* Process X events.
*/
static void event_loop(Display *dpy, Window win)
{
while (1) {
XEvent event;
if (XPending(dpy)) {
XNextEvent(dpy, &event);
switch (event.type) {
case Expose:
display(dpy, event.xexpose.window);
break;
case ConfigureNotify:
Width = event.xconfigure.width;
Height = event.xconfigure.height,
make_shape_mask(dpy, win, Width, Height, Sides);
reshape(Width, Height);
break;
case KeyPress:
{
char buf[100];
KeySym keySym;
XComposeStatus stat;
XLookupString(&event.xkey, buf, sizeof(buf), &keySym, &stat);
switch (keySym) {
case XK_Escape:
exit(0);
break;
case XK_Up:
Sides++;
if (Sides>MaxSides) Sides = MaxSides;
make_shape_mask(dpy, win, Width, Height, Sides);
break;
case XK_Down:
Sides--;
if (Sides<MinSides) Sides = MinSides;
make_shape_mask(dpy, win, Width, Height, Sides);
break;
}
}
break;
default:
;;
}
}
else {
idle();
if (Redraw) {
display(dpy, win);
Redraw = 0;
}
}
}
}
/*
* Allocate a "nice" colormap. This could be better (HP-CR support, etc).
*/
static Colormap alloc_colormap(Display *dpy, Window parent, Visual *vis)
{
Screen *scr = DefaultScreenOfDisplay(dpy);
int scrnum = DefaultScreen(dpy);
if (MaxCmapsOfScreen(scr)==1 && vis==DefaultVisual(dpy, scrnum)) {
/* The window and root are of the same visual type so */
/* share the root colormap. */
return DefaultColormap(dpy, scrnum);
}
else {
return XCreateColormap(dpy, parent, vis, AllocNone);
}
}
int main(int argc, char *argv[])
{
static int glAttribs[] = {
GLX_DOUBLEBUFFER,
GLX_RGBA,
GLX_DEPTH_SIZE, 1,
None
};
Display *dpy;
XVisualInfo *visInfo;
int scrn;
Window root;
Colormap cmap;
Window win;
XSetWindowAttributes winAttribs;
unsigned long winAttribsMask;
GLXContext glCtx;
int ignore;
dpy = XOpenDisplay(NULL);
if (!dpy) {
fprintf(stderr, "Couldn't open default display\n");
return 1;
}
/* check that we can use the shape extension */
if (!XQueryExtension(dpy, "SHAPE", &ignore, &ignore, &ignore )) {
fprintf(stderr, "Display doesn't support shape extension\n");
return 1;
}
scrn = DefaultScreen(dpy);
root = RootWindow(dpy, scrn);
visInfo = glXChooseVisual(dpy, scrn, glAttribs);
if (!visInfo) {
fprintf(stderr, "Couldn't get RGB, DB, Z visual\n");
return 1;
}
glCtx = glXCreateContext(dpy, visInfo, 0, True);
if (!glCtx) {
fprintf(stderr, "Couldn't create GL context\n");
return 1;
}
cmap = alloc_colormap(dpy, root, visInfo->visual);
if (!cmap) {
fprintf(stderr, "Couln't create colormap\n");
return 1;
}
winAttribs.border_pixel = 0;
winAttribs.colormap = cmap;
winAttribs.event_mask = StructureNotifyMask | ExposureMask | KeyPressMask;
winAttribsMask = CWBorderPixel | CWColormap | CWEventMask;
win = XCreateWindow(dpy, root, 0, 0, Width, Height, 0,
visInfo->depth, InputOutput,
visInfo->visual,
winAttribsMask, &winAttribs);
XMapWindow(dpy, win);
glXMakeCurrent(dpy, win, glCtx);
printf("Press ESC to exit.\n");
printf("Press up/down to change window shape.\n");
event_loop(dpy, win);
return 0;
}