2.x PGraphics thread crash

Core Library Questions

jeff_g

in Core Library Questions • 10 months ago

So I create a buffer to do some work in a separate thread so it does not delay the normal draw. This worked fine in 1.x. Any thoughts on why this now crashes and how to get around it?

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
PGraphics buffer;
boolean runthread = false;
ExecutorService executor;
void setup() {
size(width, height, P3D);
buffer = createGraphics(width, height, P3D);
executor = Executors.newFixedThreadPool(1);
}
void draw() {
//do stuff
stroke(random(0,255),random(0,255),random(0,255));
line(random(0,width),random(0,height),random(0,width),random(0,height));
if (!runthread) {
runthread = true;
executor.submit(new RunLoadNodes());
}
}
void loadbuffer() {
println("ya");
buffer.beginDraw();
//do stuff
buffer.endDraw();
}
public class RunLoadNodes implements Runnable {
public RunLoadNodes() {
}
public void run() {
loadbuffer();
}
}

If it helps, here is the crash info:

Application Specific Information:
Java information:
Exception type: Bus Error (0xa) at pc=00000000956d6ea4

Java VM: Java HotSpot(TM) Client VM (20.12-b01-434 mixed mode macosx-x86)

Current thread (0000000002450400): JavaThread "pool-1-thread-1" [_thread_in_native, id=-1314140160, stack(00000000b19bd000,00000000b1abd000)]
Stack: [00000000b19bd000,00000000b1abd000]
Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
j jogamp.opengl.gl4.GL4bcImpl.dispatch_glGetError1(J)I+0
j jogamp.opengl.gl4.GL4bcImpl.glGetError()I+33
j processing.opengl.PGL.getError()I+3
j processing.opengl.PGraphicsOpenGL.report(Ljava/lang/String;)V+13
j processing.opengl.PGraphicsOpenGL.beginDraw()V+3
j sketch_Dec12a.loadbuffer()V+9
j sketch_Dec12a$RunLoadNodes.run()V+4
j java.util.concurrent.Executors$RunnableAdapter.call()Ljava/lang/Object;+4
j java.util.concurrent.FutureTask$Sync.innerRun()V+30
j java.util.concurrent.FutureTask.run()V+4
j java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Ljava/lang/Runnable;)V+59
j java.util.concurrent.ThreadPoolExecutor$Worker.run()V+28
j java.lang.Thread.run()V+11
v ~StubRoutines::call_stub

Replies(4)

andres

Re: 2.x PGraphics thread crash

10 months ago

A P2D/P3D buffer is OpenGL-backed now (the old software-based P3D is gone in 2.0). OpenGL cannot be used from a thread different from the main thread that created the GL context.

jeff_g

Re: 2.x PGraphics thread crash

10 months ago

Andres, any way to create another GL context separate from the one being used to draw? I use this a lot for color picking. Or perhaps, is their a suitable replacement that may not depend on the GL for this process?

jeff_g

Re: 2.x PGraphics thread crash

10 months ago

I got this to work... not sure how safe it is though....

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
PGraphics buffer;
boolean runthread = false;
ExecutorService executor;
PGraphicsOpenGL pgl;
PGL pglx;
void setup() {
size(width, height, P3D);
buffer = createGraphics(width, height, P3D);
executor = Executors.newFixedThreadPool(1);
pgl = (PGraphicsOpenGL) g;
pglx = pgl.beginPGL();
//pglx.context.setGLDebugSynchronous(true);
}
void draw() {
//do stuff
stroke(random(0,255),random(0,255),random(0,255));
line(random(0,width),random(0,height),random(0,width),random(0,height));
if (!runthread) {
runthread = true;
executor.submit(new RunLoadNodes());
}
}
void loadbuffer() {
println("ya");
pglx.context.makeCurrent();
buffer.beginDraw();
//do stuff
buffer.endDraw();
pglx.context.release();
}
public class RunLoadNodes implements Runnable {
public RunLoadNodes() {
}
public void run() {
loadbuffer();
}
}

andres

Re: 2.x PGraphics thread crash

10 months ago

thanks for the info. I opened an enhancement request in the issue tracker about this problem.

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