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GLCanvas: "Unsupported color depth" on VmWare Linux [message #1860196]

Fri, 21 July 2023 12:23

Tom Wheeler

Messages: 17
Registered: June 2018

Junior Member

I have an Eclipse RCP application that uses SWT's GLCanvas for OpenGL graphics. It works fine on Windows-10 and -11 as well as on a native Linux PC.

However, when running my application on a Fedora (34) Linux inside a VmWare Workstation Pro (17.0.2), I get an "org.eclipse.swt.SWTException: Unsupported color depth".

To dig into the problem, I installed the org.eclipse.swt sources and created a small Java test code. This way I found out that the line failing in GLCanvas is:

long infoPtr = GLX.glXChooseVisual (xDisplay, OS.XDefaultScreen (xDisplay), glxAttrib);

After this method call, 'inforPtr' is 0, which means that the call has failed.

Here is my Java test code:

package openglexperiments;

import org.eclipse.swt.SWT;

public class GLExperiments {

	public void go() {
		Display display = new Display();
		Shell shell = new Shell(display);
		shell.setText("OpenGL Experiments");
		shell.setSize(600, 400);
		shell.open();

		GLData data = new GLData();
//        data.doubleBuffer = true;
//        data.depthSize = 32;
//        data.sampleBuffers = 1;
//        data.samples = 4;
//        data.redSize = 8;
//        data.greenSize = 8;
//        data.blueSize = 8;
//        data.alphaSize = 8;
		System.out.println("data=" + data);
		GLCanvas glcanvas = new GLCanvas(shell, SWT.NONE, data);

		while (!shell.isDisposed()) {
			if (!display.readAndDispatch())
				display.sleep();
		}
		display.dispose();
	}

	public static void main(String[] args) {
		GLExperiments glExperiments = new GLExperiments();
		glExperiments.go();
		System.exit(0);
	}
}

I did experiment a little with the contents of GLData but even when not setting any of its attributes, it still failed.

I then wanted to see if a C-code program that uses glXChooseVisual() could run fine.

I got the C-source code from here:
https://www.khronos.org/opengl/wiki/Programming_OpenGL_in_Linux:_GLX_and_Xlib

// -- Written in C -- //

#include<stdio.h>
#include<stdlib.h>
#include<X11/X.h>
#include<X11/Xlib.h>
#include<GL/gl.h>
#include<GL/glx.h>
#include<GL/glu.h>

Display                 *dpy;
Window                  root;
GLint                   att[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None };
XVisualInfo             *vi;
Colormap                cmap;
XSetWindowAttributes    swa;
Window                  win;
GLXContext              glc;
XWindowAttributes       gwa;
XEvent                  xev;

void DrawAQuad() {
 glClearColor(1.0, 1.0, 1.0, 1.0);
 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

 glMatrixMode(GL_PROJECTION);
 glLoadIdentity();
 glOrtho(-1., 1., -1., 1., 1., 20.);

 glMatrixMode(GL_MODELVIEW);
 glLoadIdentity();
 gluLookAt(0., 0., 10., 0., 0., 0., 0., 1., 0.);

 glBegin(GL_QUADS);
  glColor3f(1., 0., 0.); glVertex3f(-.75, -.75, 0.);
  glColor3f(0., 1., 0.); glVertex3f( .75, -.75, 0.);
  glColor3f(0., 0., 1.); glVertex3f( .75,  .75, 0.);
  glColor3f(1., 1., 0.); glVertex3f(-.75,  .75, 0.);
 glEnd();
} 
 
int main(int argc, char *argv[]) {

 dpy = XOpenDisplay(NULL);
 
 if(dpy == NULL) {
 	printf("\n\tcannot connect to X server\n\n");
        exit(0);
 }
        
 root = DefaultRootWindow(dpy);

 vi = glXChooseVisual(dpy, 0, att);

 if(vi == NULL) {
	printf("\n\tno appropriate visual found\n\n");
        exit(0);
 } 
 else {
	printf("\n\tvisual %p selected\n", (void *)vi->visualid); /* %p creates hexadecimal output like in glxinfo */
 }

 cmap = XCreateColormap(dpy, root, vi->visual, AllocNone);

 swa.colormap = cmap;
 swa.event_mask = ExposureMask | KeyPressMask;
 
 win = XCreateWindow(dpy, root, 0, 0, 600, 600, 0, vi->depth, InputOutput, vi->visual, CWColormap | CWEventMask, &swa);

 XMapWindow(dpy, win);
 XStoreName(dpy, win, "VERY SIMPLE APPLICATION");
 
 glc = glXCreateContext(dpy, vi, NULL, GL_TRUE);
 glXMakeCurrent(dpy, win, glc);
 
 glEnable(GL_DEPTH_TEST); 
 
 while(1) {
 	XNextEvent(dpy, &xev);
        
        if(xev.type == Expose) {
        	XGetWindowAttributes(dpy, win, &gwa);
                glViewport(0, 0, gwa.width, gwa.height);
        	DrawAQuad(); 
                glXSwapBuffers(dpy, win);
        }
                
	else if(xev.type == KeyPress) {
        	glXMakeCurrent(dpy, None, NULL);
 		glXDestroyContext(dpy, glc);
 		XDestroyWindow(dpy, win);
 		XCloseDisplay(dpy);
 		exit(0);
        }
    } /* this closes while(1) { */
} /* this is the } which closes int main(int argc, char *argv[]) { */

The code is compiled using this command:

gcc -o quad quad.c -lX11 -lGL -lGLU

Somewhat surprisingly, it turned out that the C-code program worked just fine. This proves that OpenGL is working on my virtual Linux but I am not able to use it from GLCanvas.

Here is a little bit of the output from glxinfo:
Quote:

Extended renderer info (GLX_MESA_query_renderer):
Vendor: VMware, Inc. (0x15ad)
Device: SVGA3D; build: RELEASE; LLVM; (0x405)
Version: 21.1.8
Accelerated: no
Video memory: 1MB
Unified memory: no
Preferred profile: core (0x1)
Max core profile version: 3.3
Max compat profile version: 3.3
Max GLES1 profile version: 1.1
Max GLES[23] profile version: 2.0
OpenGL vendor string: VMware, Inc.
OpenGL renderer string: SVGA3D; build: RELEASE; LLVM;
OpenGL core profile version string: 3.3 (Core Profile) Mesa 21.1.8
OpenGL core profile shading language version string: 3.30