--- /dev/null
+/*
+ * Create several OpenGL rendering contexts, sharing textures, display
+ * lists, etc. Exercise binding, deleting, etc.
+ *
+ * Brian Paul
+ * 21 December 2004
+ */
+
+
+#include <GL/gl.h>
+#include <GL/glx.h>
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <X11/keysym.h>
+
+
+/*
+ * Each display/window/context:
+ */
+struct context {
+ char DisplayName[1000];
+ Display *Dpy;
+ Window Win;
+ GLXContext Context;
+};
+
+
+#define MAX_CONTEXTS 200
+static struct context Contexts[MAX_CONTEXTS];
+static int NumContexts = 0;
+
+
+static void
+Error(const char *display, const char *msg)
+{
+ fprintf(stderr, "Error on display %s - %s\n", display, msg);
+ exit(1);
+}
+
+
+static struct context *
+CreateContext(const char *displayName, const char *name)
+{
+ Display *dpy;
+ Window win;
+ GLXContext ctx;
+ int attrib[] = { GLX_RGBA,
+ GLX_RED_SIZE, 1,
+ GLX_GREEN_SIZE, 1,
+ GLX_BLUE_SIZE, 1,
+ GLX_DOUBLEBUFFER,
+ None };
+ int scrnum;
+ XSetWindowAttributes attr;
+ unsigned long mask;
+ Window root;
+ XVisualInfo *visinfo;
+ int width = 90, height = 90;
+ int xpos = 0, ypos = 0;
+
+ if (NumContexts >= MAX_CONTEXTS)
+ return NULL;
+
+ dpy = XOpenDisplay(displayName);
+ if (!dpy) {
+ Error(displayName, "Unable to open display");
+ return NULL;
+ }
+
+ scrnum = DefaultScreen(dpy);
+ root = RootWindow(dpy, scrnum);
+
+ visinfo = glXChooseVisual(dpy, scrnum, attrib);
+ if (!visinfo) {
+ Error(displayName, "Unable to find RGB, double-buffered visual");
+ return NULL;
+ }
+
+ /* window attributes */
+ xpos = (NumContexts % 10) * 100;
+ ypos = (NumContexts / 10) * 100;
+ 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, xpos, ypos, width, height,
+ 0, visinfo->depth, InputOutput,
+ visinfo->visual, mask, &attr);
+ if (!win) {
+ Error(displayName, "Couldn't create window");
+ return NULL;
+ }
+
+ {
+ XSizeHints sizehints;
+ sizehints.x = xpos;
+ sizehints.y = ypos;
+ sizehints.width = width;
+ sizehints.height = height;
+ sizehints.flags = USSize | USPosition;
+ XSetNormalHints(dpy, win, &sizehints);
+ XSetStandardProperties(dpy, win, name, name,
+ None, (char **)NULL, 0, &sizehints);
+ }
+
+ if (NumContexts == 0) {
+ ctx = glXCreateContext(dpy, visinfo, NULL, True);
+ }
+ else {
+ /* share textures & dlists with 0th context */
+ ctx = glXCreateContext(dpy, visinfo, Contexts[0].Context, True);
+ }
+ if (!ctx) {
+ Error(displayName, "Couldn't create GLX context");
+ return NULL;
+ }
+
+ XMapWindow(dpy, win);
+
+ if (!glXMakeCurrent(dpy, win, ctx)) {
+ Error(displayName, "glXMakeCurrent failed");
+ return NULL;
+ }
+
+ if (NumContexts == 0) {
+ printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
+ }
+
+ /* save the info for this context */
+ {
+ struct context *h = &Contexts[NumContexts];
+ strcpy(h->DisplayName, name);
+ h->Dpy = dpy;
+ h->Win = win;
+ h->Context = ctx;
+ NumContexts++;
+ return &Contexts[NumContexts-1];
+ }
+}
+
+
+static void
+MakeCurrent(int i)
+{
+ if (!glXMakeCurrent(Contexts[i].Dpy, Contexts[i].Win, Contexts[i].Context)) {
+ fprintf(stderr, "glXMakeCurrent failed!\n");
+ }
+}
+
+
+
+static void
+DestroyContext(int i)
+{
+ XDestroyWindow(Contexts[i].Dpy, Contexts[i].Win);
+ glXDestroyContext(Contexts[i].Dpy, Contexts[i].Context);
+ XCloseDisplay(Contexts[i].Dpy);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+ char *dpyName = NULL;
+ int i;
+ GLuint t;
+ GLint tb;
+
+ for (i = 0; i < 2; i++) {
+ CreateContext(dpyName, "context");
+ }
+
+ /* Create texture and bind it in context 0 */
+ MakeCurrent(0);
+ glGenTextures(1, &t);
+ printf("Generated texture ID %u\n", t);
+ assert(!glIsTexture(t));
+ glBindTexture(GL_TEXTURE_2D, t);
+ assert(glIsTexture(t));
+ glGetIntegerv(GL_TEXTURE_BINDING_2D, &tb);
+ assert(tb == t);
+
+ /* Bind texture in context 1 */
+ MakeCurrent(1);
+ assert(glIsTexture(t));
+ glBindTexture(GL_TEXTURE_2D, t);
+ glGetIntegerv(GL_TEXTURE_BINDING_2D, &tb);
+ assert(tb == t);
+
+ /* Delete texture from context 0 */
+ MakeCurrent(0);
+ glDeleteTextures(1, &t);
+ assert(!glIsTexture(t));
+ glGetIntegerv(GL_TEXTURE_BINDING_2D, &tb);
+ printf("After delete, binding = %d\n", tb);
+
+ /* Check texture state from context 1 */
+ MakeCurrent(1);
+ assert(!glIsTexture(t));
+ glGetIntegerv(GL_TEXTURE_BINDING_2D, &tb);
+ printf("In second context, binding = %d\n", tb);
+ glBindTexture(GL_TEXTURE_2D, 0);
+ glGetIntegerv(GL_TEXTURE_BINDING_2D, &tb);
+ assert(tb == 0);
+
+
+ for (i = 0; i < NumContexts; i++) {
+ DestroyContext(i);
+ }
+
+ printf("Success!\n");
+
+ return 0;
+}