1
2/* This is a good test for glXSwapBuffers on non-current windows,
3 * and the glXCopyContext function.  Fixed several Mesa/DRI bugs with
4 * this program on 15 June 2002.
5 *
6 * Joe's comments follow:
7 *
8 * I have tried some different approaches for being able to
9 * draw to multiple windows using one context, or a copied
10 * context. Mesa/indirect rendering works to use one context
11 * for multiple windows, but crashes with glXCopyContext.
12 * DRI is badly broken, at least for ATI.
13 *
14 * I also noticed that glXMakeCurrent allows a window and context
15 * from different visuals to be attached (haven't tested recently).
16 *
17 * Joe Krahn  <jkrahn@nc.rr.com>
18 */
19
20#include <GL/glx.h>
21#include <GL/gl.h>
22#include <string.h>
23#include <stdio.h>
24#include <stdlib.h>
25#include <unistd.h>
26#include <math.h>
27
28#ifndef M_PI
29#define M_PI 3.14159
30#endif
31
32#define DEGTOR (M_PI/180.0)
33
34static int AttributeList[] = { GLX_RGBA, GLX_DOUBLEBUFFER, None };
35
36int main(int argc, char **argv)
37{
38    Window win1, win2;
39    XVisualInfo *vi;
40    XSetWindowAttributes swa;
41    Display *dpy;
42    GLXContext ctx1, ctx2;
43    float angle;
44    int test;
45
46    if (argc < 2) {
47       fprintf(stderr, "This program tests GLX context switching.\n");
48       fprintf(stderr, "Usage: jkrahntest <n>\n");
49       fprintf(stderr, "Where n is:\n");
50       fprintf(stderr, "\t1) Use two contexts and swap only when the context is current (typical case).\n");
51       fprintf(stderr, "\t2) Use two contexts and swap at the same time.\n");
52       fprintf(stderr, "\t\t Used to crash Mesa & nVidia, and DRI artifacts. Seems OK now.\n");
53       fprintf(stderr, "\t3) Use one context, but only swap when a context is current.\n");
54       fprintf(stderr, "\t\t Serious artifacts for DRI at least with ATI.\n");
55       fprintf(stderr, "\t4) Use one context, swap both windows at the same time, so the left\n");
56       fprintf(stderr, "\t\t window has no context at swap time. Severe artifacts for DRI.\n");
57       fprintf(stderr, "\t5) Use two contexts, copying one to the other when switching windows.\n");
58       fprintf(stderr, "\t\t DRI gives an error, indirect rendering crashes server.\n");
59
60	exit(1);
61    }
62    test = atoi(argv[1]);
63
64    /* get a connection */
65    dpy = XOpenDisplay(NULL);
66
67    /* Get an appropriate visual */
68    vi = glXChooseVisual(dpy, DefaultScreen(dpy), AttributeList);
69    if (vi == 0) {
70	fprintf(stderr, "No matching visuals found.\n");
71	exit(-1);
72    }
73
74    /* Create two GLX contexts, with list sharing */
75    ctx1 = glXCreateContext(dpy, vi, 0, True);
76    ctx2 = glXCreateContext(dpy, vi, ctx1, True);
77
78    /* create a colormap */
79    swa.colormap = XCreateColormap(dpy, RootWindow(dpy, vi->screen),
80       vi->visual, AllocNone);
81    swa.border_pixel = 0;
82
83    /* Create two windows */
84    win1 = XCreateWindow(dpy, RootWindow(dpy, vi->screen),
85       10, 10, 200, 200,
86       0, vi->depth, InputOutput, vi->visual,
87       CWBorderPixel | CWColormap, &swa);
88    XStoreName(dpy, win1, "Test [L]");
89    XMapWindow(dpy, win1);
90    XMoveWindow(dpy, win1, 10, 10); /* Initial requested x,y may not be honored */
91   {
92      XSizeHints sizehints;
93      static const char *name = "window";
94      sizehints.x = 10;
95      sizehints.y = 10;
96      sizehints.width  = 200;
97      sizehints.height = 200;
98      sizehints.flags = USSize | USPosition;
99      XSetNormalHints(dpy, win1, &sizehints);
100      XSetStandardProperties(dpy, win1, name, name,
101                              None, (char **)NULL, 0, &sizehints);
102   }
103
104
105    win2 = XCreateWindow(dpy, RootWindow(dpy, vi->screen),
106       250, 10, 200, 200,
107       0, vi->depth, InputOutput, vi->visual,
108       CWBorderPixel | CWColormap, &swa);
109    XStoreName(dpy, win1, "Test [R]");
110    XMapWindow(dpy, win2);
111    XMoveWindow(dpy, win2, 260, 10);
112   {
113      XSizeHints sizehints;
114      static const char *name = "window";
115      sizehints.x = 10;
116      sizehints.y = 10;
117      sizehints.width  = 200;
118      sizehints.height = 200;
119      sizehints.flags = USSize | USPosition;
120      XSetNormalHints(dpy, win2, &sizehints);
121      XSetStandardProperties(dpy, win2, name, name,
122                              None, (char **)NULL, 0, &sizehints);
123   }
124
125
126    /* Now draw some spinning things */
127    for (angle = 0; angle < 360*4; angle += 10.0) {
128	/* Connect the context to window 1 */
129	glXMakeCurrent(dpy, win1, ctx1);
130
131	/* Clear and draw in window 1 */
132	glDrawBuffer(GL_BACK);
133	glClearColor(1, 1, 0, 1);
134	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
135	glColor3f(1, 0, 0);
136	glBegin(GL_TRIANGLES);
137	glVertex2f(0, 0);
138	glVertex2f(cos(angle * DEGTOR), sin(angle * DEGTOR));
139	glVertex2f(cos((angle + 20.0) * DEGTOR),
140	   sin((angle + 20.0) * DEGTOR));
141	glEnd();
142        glFlush();
143
144	if (test == 1 || test == 3 || test == 5)
145	    glXSwapBuffers(dpy, win1);
146
147	if (test == 5)
148	    glXCopyContext(dpy, ctx1, ctx2, GL_ALL_ATTRIB_BITS);
149	/* Connect the context to window 2 */
150	if (test == 3 || test == 4) {
151	    glXMakeCurrent(dpy, win2, ctx1);
152	} else {
153	    glXMakeCurrent(dpy, win2, ctx2);
154	}
155
156	/* Clear and draw in window 2 */
157	glDrawBuffer(GL_BACK);
158	glClearColor(0, 0, 1, 1);
159	glClear(GL_COLOR_BUFFER_BIT);
160	glColor3f(1, 1, 0);
161	glBegin(GL_TRIANGLES);
162	glVertex2f(0, 0);
163	glVertex2f(cos(angle * DEGTOR), sin(angle * DEGTOR));
164	glVertex2f(cos((angle + 20.0) * DEGTOR),
165	   sin((angle + 20.0) * DEGTOR));
166	glEnd();
167        glFlush();
168
169	/* Swap buffers */
170	if (test == 2 || test == 4)
171	    glXSwapBuffers(dpy, win1);
172	glXSwapBuffers(dpy, win2);
173
174	/* wait a while */
175	glXWaitX();
176        usleep(20000);
177    }
178
179    return 0;
180}
181