--- /dev/null
+/* $Id: jkrahntest.c,v 1.1 2002/06/16 03:57:48 brianp Exp $ */
+
+/* This is a good test for glXSwapBuffers on non-current windows,
+ * and the glXCopyContext function. Fixed several Mesa/DRI bugs with
+ * this program on 15 June 2002.
+ *
+ * Joe's comments follow:
+ *
+ * I have tried some different approaches for being able to
+ * draw to multiple windows using one context, or a copied
+ * context. Mesa/indirect rendering works to use one context
+ * for multiple windows, but crashes with glXCopyContext.
+ * DRI is badly broken, at least for ATI.
+ *
+ * I also noticed that glXMakeCurrent allows a window and context
+ * from different visuals to be attached (haven't tested recently).
+ *
+ * Joe Krahn <jkrahn@nc.rr.com>
+ */
+
+#include <GL/glx.h>
+#include <GL/gl.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <math.h>
+#define M_PI 3.14159
+#define DEGTOR (M_PI/180.0)
+
+static int AttributeList[] = { GLX_RGBA, GLX_DOUBLEBUFFER, None };
+
+int main(int argc, char **argv)
+{
+ Window win1, win2;
+ XVisualInfo *vi;
+ XSetWindowAttributes swa;
+ Display *dpy;
+ GLXContext ctx1, ctx2;
+ float angle;
+ int test;
+
+ if (argc < 2) {
+ fprintf(stderr, "This program tests GLX context switching.\n");
+ fprintf(stderr, "Usage: cxbug <n>\n");
+ fprintf(stderr, "Where n is:\n");
+ fprintf(stderr, "\t1) Use two contexts and swap only when the context is current (typical case).\n");
+ fprintf(stderr, "\t2) Use two contexts and swap at the same time.\n");
+ fprintf(stderr, "\t\t Used to crash Mesa & nVidia, and DRI artifacts. Seems OK now.\n");
+ fprintf(stderr, "\t3) Use one context, but only swap when a context is current.\n");
+ fprintf(stderr, "\t\t Serious artifacts for DRI at least with ATI.\n");
+ fprintf(stderr, "\t4) Use one context, swap both windows at the same time, so the left\n");
+ fprintf(stderr, "\t\t window has no context at swap time. Severe artifacts for DRI.\n");
+ fprintf(stderr, "\t5) Use two contexts, copying one to the other when switching windows.\n");
+ fprintf(stderr, "\t\t DRI gives an error, indirect rendering crashes server.\n");
+
+ exit(1);
+ }
+ test = atoi(argv[1]);
+
+ /* get a connection */
+ dpy = XOpenDisplay(NULL);
+
+ /* Get an appropriate visual */
+ vi = glXChooseVisual(dpy, DefaultScreen(dpy), AttributeList);
+ if (vi == 0) {
+ fprintf(stderr, "No matching visuals found.\n");
+ exit(-1);
+ }
+
+ /* Create two GLX contexts, with list sharing */
+ ctx1 = glXCreateContext(dpy, vi, 0, True);
+ ctx2 = glXCreateContext(dpy, vi, ctx1, True);
+
+ /* create a colormap */
+ swa.colormap = XCreateColormap(dpy, RootWindow(dpy, vi->screen),
+ vi->visual, AllocNone);
+ swa.border_pixel = 0;
+
+ /* Create two windows */
+ win1 = XCreateWindow(dpy, RootWindow(dpy, vi->screen),
+ 10, 10, 200, 200,
+ 0, vi->depth, InputOutput, vi->visual,
+ CWBorderPixel | CWColormap, &swa);
+ XStoreName(dpy, win1, "Test [L]");
+ XMapWindow(dpy, win1);
+ XMoveWindow(dpy, win1, 10, 10); /* Initial requested x,y may not be honored */
+ {
+ XSizeHints sizehints;
+ static const char *name = "window";
+ sizehints.x = 10;
+ sizehints.y = 10;
+ sizehints.width = 200;
+ sizehints.height = 200;
+ sizehints.flags = USSize | USPosition;
+ XSetNormalHints(dpy, win1, &sizehints);
+ XSetStandardProperties(dpy, win1, name, name,
+ None, (char **)NULL, 0, &sizehints);
+ }
+
+
+ win2 = XCreateWindow(dpy, RootWindow(dpy, vi->screen),
+ 250, 10, 200, 200,
+ 0, vi->depth, InputOutput, vi->visual,
+ CWBorderPixel | CWColormap, &swa);
+ XStoreName(dpy, win1, "Test [R]");
+ XMapWindow(dpy, win2);
+ XMoveWindow(dpy, win2, 260, 10);
+ {
+ XSizeHints sizehints;
+ static const char *name = "window";
+ sizehints.x = 10;
+ sizehints.y = 10;
+ sizehints.width = 200;
+ sizehints.height = 200;
+ sizehints.flags = USSize | USPosition;
+ XSetNormalHints(dpy, win2, &sizehints);
+ XSetStandardProperties(dpy, win2, name, name,
+ None, (char **)NULL, 0, &sizehints);
+ }
+
+
+ /* Now draw some spinning things */
+ for (angle = 0; angle < 360*4; angle += 10.0) {
+ /* Connect the context to window 1 */
+ glXMakeCurrent(dpy, win1, ctx1);
+
+ /* Clear and draw in window 1 */
+ glDrawBuffer(GL_BACK);
+ glClearColor(1, 1, 0, 1);
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+ glColor3f(1, 0, 0);
+ glBegin(GL_TRIANGLES);
+ glVertex2f(0, 0);
+ glVertex2f(cos(angle * DEGTOR), sin(angle * DEGTOR));
+ glVertex2f(cos((angle + 20.0) * DEGTOR),
+ sin((angle + 20.0) * DEGTOR));
+ glEnd();
+ glFlush();
+
+ if (test == 1 || test == 3 || test == 5)
+ glXSwapBuffers(dpy, win1);
+
+ if (test == 5)
+ glXCopyContext(dpy, ctx1, ctx2, GL_ALL_ATTRIB_BITS);
+ /* Connect the context to window 2 */
+ if (test == 3 || test == 4) {
+ glXMakeCurrent(dpy, win2, ctx1);
+ } else {
+ glXMakeCurrent(dpy, win2, ctx2);
+ }
+
+ /* Clear and draw in window 2 */
+ glDrawBuffer(GL_BACK);
+ glClearColor(0, 0, 1, 1);
+ glClear(GL_COLOR_BUFFER_BIT);
+ glColor3f(1, 1, 0);
+ glBegin(GL_TRIANGLES);
+ glVertex2f(0, 0);
+ glVertex2f(cos(angle * DEGTOR), sin(angle * DEGTOR));
+ glVertex2f(cos((angle + 20.0) * DEGTOR),
+ sin((angle + 20.0) * DEGTOR));
+ glEnd();
+ glFlush();
+
+ /* Swap buffers */
+ if (test == 2 || test == 4)
+ glXSwapBuffers(dpy, win1);
+ glXSwapBuffers(dpy, win2);
+
+ /* wait a while */
+ glXWaitX();
+ usleep(20000);
+ }
+
+ return 0;
+}