I seem to get various random numbers when I call:
glGetIntegerv(GL_MAX_TEXTURE_UNITS_ARB, &num);
on the ATI Rage PRO with utah-glx-0.10-pre1.tar.gz.
Dunno if this is specific to the rage pro or more generic.
Here is a modified glxsimple.c that reproduces the problem.
/* $Revision: 1.6 $ */
/* compile: cc -o glxsimple glxsimple.c -lGL -lX11 */
#include <stdio.h>
#include <stdlib.h>
#include <GL/glx.h> /* this includes the necessary X headers */
#include <GL/gl.h>
static int snglBuf[] = {GLX_RGBA, GLX_DEPTH_SIZE, 16, None};
static int dblBuf[] = {GLX_RGBA, GLX_DEPTH_SIZE, 16, GLX_DOUBLEBUFFER, None};
Display *dpy;
Window win;
GLfloat xAngle = 42.0, yAngle = 82.0, zAngle = 112.0;
GLboolean doubleBuffer = GL_TRUE;
void
fatalError(char *message)
{
fprintf(stderr, "glxsimple: %s\n", message);
exit(1);
}
void
redraw(void)
{
static GLboolean displayListInited = GL_FALSE;
if (displayListInited) {
/* if display list already exists, just execute it */
glCallList(1);
} else {
/* otherwise compile and execute to create the display list */
glNewList(1, GL_COMPILE_AND_EXECUTE);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
/* front face */
glBegin(GL_QUADS);
glColor3f(0.0, 0.7, 0.1); /* green */
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);
/* back face */
glColor3f(0.9, 1.0, 0.0); /* yellow */
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);
/* top side face */
glColor3f(0.2, 0.2, 1.0); /* blue */
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);
/* bottom side face */
glColor3f(0.7, 0.0, 0.1); /* red */
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();
glEndList();
displayListInited = GL_TRUE;
}
if(doubleBuffer) glXSwapBuffers(dpy, win); /* buffer swap does implicit glFlush */
else glFlush(); /* explicit flush for single buffered case */
}
void
main(int argc, char **argv)
{
XVisualInfo *vi;
Colormap cmap;
XSetWindowAttributes swa;
GLXContext cx;
XEvent event;
GLboolean needRedraw = GL_FALSE, recalcModelView = GL_TRUE;
int dummy;
int num=0;
/*** (1) open a connection to the X server ***/
dpy = XOpenDisplay(NULL);
if (dpy == NULL) fatalError("could not open display");
/*** (2) make sure OpenGL's GLX extension supported ***/
if(!glXQueryExtension(dpy, &dummy, &dummy)) fatalError("X server has no OpenGL GLX extension");
/*** (3) find an appropriate visual ***/
/* find an OpenGL-capable RGB visual with depth buffer */
vi = glXChooseVisual(dpy, DefaultScreen(dpy), dblBuf);
if (vi == NULL) {
vi = glXChooseVisual(dpy, DefaultScreen(dpy), snglBuf);
if (vi == NULL) fatalError("no RGB visual with depth buffer");
doubleBuffer = GL_FALSE;
}
if(vi->class != TrueColor) fatalError("TrueColor visual required for this program");
/*** (4) create an OpenGL rendering context ***/
/* create an OpenGL rendering context */
cx = glXCreateContext(dpy, vi, /* no sharing of display lists */ None,
/* direct rendering if possible */ GL_TRUE);
if (cx == NULL) fatalError("could not create rendering context");
/*** (5) create an X window with the selected visual ***/
/* create an X colormap since probably not using default visual */
cmap = XCreateColormap(dpy, RootWindow(dpy, vi->screen), vi->visual, AllocNone);
swa.colormap = cmap;
swa.border_pixel = 0;
swa.event_mask = ExposureMask | ButtonPressMask | StructureNotifyMask;
win = XCreateWindow(dpy, RootWindow(dpy, vi->screen), 0, 0, 300, 300, 0, vi->depth,
InputOutput, vi->visual, CWBorderPixel | CWColormap | CWEventMask, &swa);
XSetStandardProperties(dpy, win, "glxsimple", "glxsimple", None, argv, argc, NULL);
/*** (6) bind the rendering context to the window ***/
glXMakeCurrent(dpy, win, cx);
/*** (7) request the X window to be displayed on the screen ***/
XMapWindow(dpy, win);
/*** (8) configure the OpenGL context for rendering ***/
glEnable(GL_DEPTH_TEST); /* enable depth buffering */
glDepthFunc(GL_LESS); /* pedantic, GL_LESS is the default */
glClearDepth(1.0); /* pedantic, 1.0 is the default */
/* frame buffer clears should be to black */
glClearColor(0.0, 0.0, 0.0, 0.0);
/* set up projection transform */
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1.0, 1.0, -1.0, 1.0, 1.0, 10.0);
/* establish initial viewport */
glViewport(0, 0, 300, 300); /* pedantic, full window size is default viewport */
glGetIntegerv(GL_MAX_TEXTURE_UNITS_ARB, &num);
fprintf(stderr, "max texture units = %d\n", num);
/*** (9) dispatch X events ***/
while (1) {
do {
XNextEvent(dpy, &event);
switch (event.type) {
case ButtonPress:
recalcModelView = GL_TRUE;
switch (event.xbutton.button) {
case 1: xAngle += 10.0; break;
case 2: yAngle += 10.0; break;
case 3: zAngle += 10.0; break;
}
break;
case ConfigureNotify:
glViewport(0, 0, event.xconfigure.width, event.xconfigure.height);
/* fall through... */
case Expose:
needRedraw = GL_TRUE;
break;
}
} while(XPending(dpy)); /* loop to compress events */
if (recalcModelView) {
glMatrixMode(GL_MODELVIEW);
/* reset modelview matrix to the identity matrix */
glLoadIdentity();
/* move the camera back three units */
glTranslatef(0.0, 0.0, -3.0);
/* rotate by X, Y, and Z angles */
glRotatef(xAngle, 0.1, 0.0, 0.0);
glRotatef(yAngle, 0.0, 0.1, 0.0);
glRotatef(zAngle, 0.0, 0.0, 1.0);
recalcModelView = GL_FALSE;
needRedraw = GL_TRUE;
}
if (needRedraw) {
redraw();
needRedraw = GL_FALSE;
}
}
}
