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-rw-r--r--progs/xdemos/glxsnoop.c377
1 files changed, 377 insertions, 0 deletions
diff --git a/progs/xdemos/glxsnoop.c b/progs/xdemos/glxsnoop.c
new file mode 100644
index 00000000000..2e951345b58
--- /dev/null
+++ b/progs/xdemos/glxsnoop.c
@@ -0,0 +1,377 @@
+/**
+ * Display/snoop the z/stencil/back/front buffers of another app's window.
+ * Also, an example of the need for shared ancillary renderbuffers.
+ *
+ * Hint: use 'xwininfo' to get a window's ID.
+ *
+ * Brian Paul
+ * 11 Oct 2007
+ */
+
+#define GL_GLEXT_PROTOTYPES
+
+#include <GL/gl.h>
+#include <GL/glx.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <X11/keysym.h>
+
+
+#define Z_BUFFER 1
+#define STENCIL_BUFFER 2
+#define BACK_BUFFER 3
+#define FRONT_BUFFER 4
+
+
+static int Buffer = BACK_BUFFER;
+static int WindowID = 0;
+static const char *DisplayName = NULL;
+static GLXContext Context = 0;
+static int Width, Height;
+
+
+/**
+ * Grab the z/stencil/back/front image from the srcWin and display it
+ * (possibly converted to grayscale) in the dstWin.
+ */
+static void
+redraw(Display *dpy, Window srcWin, Window dstWin )
+{
+ GLubyte *image = malloc(Width * Height * 4);
+
+ glXMakeCurrent(dpy, srcWin, Context);
+ glPixelStorei(GL_PACK_ALIGNMENT, 1);
+ if (Buffer == BACK_BUFFER) {
+ glReadBuffer(GL_BACK);
+ glReadPixels(0, 0, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, image);
+ }
+ else if (Buffer == FRONT_BUFFER) {
+ glReadBuffer(GL_FRONT);
+ glReadPixels(0, 0, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, image);
+ }
+ else if (Buffer == Z_BUFFER) {
+ GLfloat *z = malloc(Width * Height * sizeof(GLfloat));
+ int i;
+ glReadPixels(0, 0, Width, Height, GL_DEPTH_COMPONENT, GL_FLOAT, z);
+ for (i = 0; i < Width * Height; i++) {
+ image[i*4+0] =
+ image[i*4+1] =
+ image[i*4+2] = (GLint) (255.0 * z[i]);
+ image[i*4+3] = 255;
+ }
+ free(z);
+ }
+ else if (Buffer == STENCIL_BUFFER) {
+ GLubyte *sten = malloc(Width * Height * sizeof(GLubyte));
+ int i, min = 100, max = -1;
+ float step;
+ int sz;
+ glGetIntegerv(GL_STENCIL_BITS, &sz);
+ glReadPixels(0, 0, Width, Height,
+ GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, sten);
+ /* find min/max for converting stencil to grayscale */
+ for (i = 0; i < Width * Height; i++) {
+ if (sten[i] < min)
+ min = sten[i];
+ if (sten[i] > max)
+ max = sten[i];
+ }
+ if (min == max)
+ step = 0;
+ else
+ step = 255.0 / (float) (max - min);
+ for (i = 0; i < Width * Height; i++) {
+ image[i*4+0] =
+ image[i*4+1] =
+ image[i*4+2] = (GLint) ((sten[i] - min) * step);
+ image[i*4+3] = 255;
+ }
+ free(sten);
+ }
+
+ glXMakeCurrent(dpy, dstWin, Context);
+ glWindowPos2iARB(0, 0);
+ glDrawBuffer(GL_FRONT);
+ glDrawPixels(Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, image);
+ glFlush();
+
+ free(image);
+}
+
+
+static void
+set_window_title(Display *dpy, Window win, const char *title)
+{
+ XSizeHints sizehints;
+ sizehints.flags = 0;
+ XSetStandardProperties(dpy, win, title, title,
+ None, (char **)NULL, 0, &sizehints);
+}
+
+
+static Window
+make_gl_window(Display *dpy, XVisualInfo *visinfo, int width, int height)
+{
+ int scrnum;
+ XSetWindowAttributes attr;
+ unsigned long mask;
+ Window root;
+ Window win;
+ int x = 0, y = 0;
+ char *name = NULL;
+
+ scrnum = DefaultScreen( dpy );
+ root = RootWindow( dpy, scrnum );
+
+ /* window attributes */
+ attr.background_pixel = 0;
+ attr.border_pixel = 0;
+ attr.colormap = XCreateColormap( dpy, root, visinfo->visual, AllocNone);
+ attr.event_mask = StructureNotifyMask | ExposureMask | KeyPressMask;
+ mask = CWBackPixel | CWBorderPixel | CWColormap | CWEventMask;
+
+ win = XCreateWindow( dpy, root, x, y, width, height,
+ 0, visinfo->depth, InputOutput,
+ visinfo->visual, mask, &attr );
+
+ /* set hints and properties */
+ {
+ XSizeHints sizehints;
+ sizehints.x = x;
+ sizehints.y = y;
+ sizehints.width = width;
+ sizehints.height = height;
+ sizehints.flags = USSize | USPosition;
+ XSetNormalHints(dpy, win, &sizehints);
+ XSetStandardProperties(dpy, win, name, name,
+ None, (char **)NULL, 0, &sizehints);
+ }
+
+ return win;
+}
+
+
+static void
+update_window_title(Display *dpy, Window win)
+{
+ char title[1000], *buf;
+
+ switch (Buffer) {
+ case Z_BUFFER:
+ buf = "Z";
+ break;
+ case STENCIL_BUFFER:
+ buf = "Stencil";
+ break;
+ case BACK_BUFFER:
+ buf = "Back";
+ break;
+ case FRONT_BUFFER:
+ buf = "Front";
+ break;
+ default:
+ buf = "";
+ }
+
+ sprintf(title, "glxsnoop window 0x%x (%s buffer)", (int) WindowID, buf);
+
+ set_window_title(dpy, win, title);
+}
+
+
+static void
+keypress(Display *dpy, Window win, char key)
+{
+ switch (key) {
+ case 27:
+ /* escape */
+ exit(0);
+ break;
+ case 's':
+ Buffer = STENCIL_BUFFER;
+ break;
+ case 'z':
+ Buffer = Z_BUFFER;
+ break;
+ case 'f':
+ Buffer = FRONT_BUFFER;
+ break;
+ case 'b':
+ Buffer = BACK_BUFFER;
+ break;
+ default:
+ return;
+ }
+
+ update_window_title(dpy, win);
+ redraw(dpy, WindowID, win);
+}
+
+
+static void
+event_loop(Display *dpy, Window win)
+{
+ XEvent event;
+
+ while (1) {
+ XNextEvent( dpy, &event );
+
+ switch (event.type) {
+ case Expose:
+ redraw(dpy, WindowID, win);
+ break;
+ case ConfigureNotify:
+ /*resize( event.xconfigure.width, event.xconfigure.height );*/
+ break;
+ case KeyPress:
+ {
+ char buffer[10];
+ int r, code;
+ code = XLookupKeysym(&event.xkey, 0);
+ if (code == XK_Left) {
+ }
+ else {
+ r = XLookupString(&event.xkey, buffer, sizeof(buffer),
+ NULL, NULL);
+ keypress(dpy, win, buffer[0]);
+ }
+ }
+ default:
+ /* nothing */
+ ;
+ }
+ }
+}
+
+
+static VisualID
+get_window_visualid(Display *dpy, Window win)
+{
+ XWindowAttributes attr;
+
+ if (XGetWindowAttributes(dpy, win, &attr)) {
+ return attr.visual->visualid;
+ }
+ else {
+ return 0;
+ }
+}
+
+
+static void
+get_window_size(Display *dpy, Window win, int *w, int *h)
+{
+ XWindowAttributes attr;
+
+ if (XGetWindowAttributes(dpy, win, &attr)) {
+ *w = attr.width;
+ *h = attr.height;
+ }
+ else {
+ *w = *h = 0;
+ }
+}
+
+
+static XVisualInfo *
+visualid_to_visualinfo(Display *dpy, VisualID vid)
+{
+ XVisualInfo *vinfo, templ;
+ long mask;
+ int n;
+
+ templ.visualid = vid;
+ mask = VisualIDMask;
+
+ vinfo = XGetVisualInfo(dpy, mask, &templ, &n);
+ return vinfo;
+}
+
+
+static void
+key_usage(void)
+{
+ printf("Keyboard:\n");
+ printf(" z - display Z buffer\n");
+ printf(" s - display stencil buffer\n");
+ printf(" f - display front color buffer\n");
+ printf(" b - display back buffer\n");
+}
+
+
+static void
+usage(void)
+{
+ printf("Usage: glxsnoop [-display dpy] windowID\n");
+ key_usage();
+}
+
+
+static void
+parse_opts(int argc, char *argv[])
+{
+ int i;
+
+ for (i = 1; i < argc; i++) {
+ if (strcmp(argv[i], "-h") == 0) {
+ usage();
+ exit(0);
+ }
+ else if (strcmp(argv[i], "-display") == 0) {
+ DisplayName = argv[i + 1];
+ i++;
+ }
+ else {
+ if (argv[i][0] == '0' && argv[i][1] == 'x') {
+ /* hex */
+ WindowID = strtol(argv[i], NULL, 16);
+ }
+ else {
+ WindowID = atoi(argv[i]);
+ }
+ break;
+ }
+ }
+
+ if (!WindowID) {
+ usage();
+ exit(0);
+ }
+}
+
+
+int
+main( int argc, char *argv[] )
+{
+ Display *dpy;
+ VisualID vid;
+ XVisualInfo *visinfo;
+ Window win;
+
+ parse_opts(argc, argv);
+
+ key_usage();
+
+ dpy = XOpenDisplay(DisplayName);
+
+ /* find the VisualID for the named window */
+ vid = get_window_visualid(dpy, WindowID);
+ get_window_size(dpy, WindowID, &Width, &Height);
+
+ visinfo = visualid_to_visualinfo(dpy, vid);
+
+ Context = glXCreateContext( dpy, visinfo, NULL, True );
+ if (!Context) {
+ printf("Error: glXCreateContext failed\n");
+ exit(1);
+ }
+
+ win = make_gl_window(dpy, visinfo, Width, Height);
+ XMapWindow(dpy, win);
+ update_window_title(dpy, win);
+
+ event_loop( dpy, win );
+
+ return 0;
+}
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