[Bug] gl.glGenFramebuffersEXT Causes JVM Crash

[Phenix]

I am writing a small game in java and started coded a FBO class. When I tested it the following appeared in my console

[quote]#

An unexpected error has been detected by Java Runtime Environment:

EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x6959e29b, pid=1872, tid=3616

Java VM: Java HotSpot™ Client VM (10.0-b22 mixed mode, sharing windows-x86)

Problematic frame:

C [nvoglv32.dll+0x9e29b]

An error report file with more information is saved as:

J:\Programming\Java\Game Workspace\Game\hs_err_pid1872.log

If you would like to submit a bug report, please visit:

http://java.sun.com/webapps/bugreport/crash.jsp

The crash happened outside the Java Virtual Machine in native code.

See problematic frame for where to report the bug.

[/quote]
Using the following code (The code is called from the display method of my Canvas - so the thread has got context):

		//Get the openGL object (with context!)
		GL gl = GraphicsManager.getGL();
		
		//Create a valid handle to manage the frame buffer
		//this.intBuffer = IntBuffer.allocate(1);
		//gl.glGenFramebuffersEXT(1, this.intBuffer);
		gl.glGenFramebuffersEXT(1, ints, 0);
		this.fbo = ints[0]; 
		//this.fbo = this.intBuffer.get(0);
		
		//Bind the FBO
		gl.glBindFramebufferEXT(GL.GL_FRAMEBUFFER_EXT, this.fbo);
		
		//Create a depth buffer
		//this.intBuffer = IntBuffer.allocate(1);
		gl.glGenRenderbuffersEXT(1, ints, 1); //this.intBuffer);
		this.depthBuffer = ints[1];
		//this.depthBuffer = this.intBuffer.get(0);
		
		//Bind the render buffer
		gl.glBindRenderbufferEXT(GL.GL_RENDERBUFFER_EXT, this.depthBuffer);
		
		//Tell openGL how much storeage space we want for the render buffer
		gl.glRenderbufferStorageEXT(GL.GL_RENDERBUFFER_EXT, GL.GL_DEPTH_COMPONENT, width, height);
		
		//Now attach the render buffer to the FBO we created
		gl.glFramebufferRenderbufferEXT(GL.GL_FRAMEBUFFER_EXT, GL.GL_DEPTH_ATTACHMENT_EXT, GL.GL_RENDERBUFFER_EXT, this.depthBuffer);
		
		//Create a texture handle
		//this.intBuffer = IntBuffer.allocate(1);
		gl.glGenTextures(1, ints, 2); //this.intBuffer);
		this.color_texture = ints[2];
		//this.color_texture = this.intBuffer.get(0);
		
		//Bind the handle as a 2D texture
		gl.glBindTexture(GL.GL_TEXTURE_2D, this.color_texture);
		
		//Set texture parameters
		gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_LINEAR);
		gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_LINEAR);
		gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_S, GL.GL_CLAMP_TO_EDGE);
		gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_T, GL.GL_CLAMP_TO_EDGE);

		//Create a image of the same width and height as the render buffer
		gl.glTexImage2D(GL.GL_TEXTURE_2D, 0, GL.GL_RGBA8, width, height, 0, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, null);
		
		//Attach the colour texture to the FBO
		gl.glFramebufferTexture2DEXT(GL.GL_FRAMEBUFFER_EXT, GL.GL_COLOR_ATTACHMENT0_EXT, GL.GL_TEXTURE_2D, this.color_texture, 0);
		
		
		int status = gl.glCheckFramebufferStatusEXT(GL.GL_FRAMEBUFFER_EXT);
		
		this.active = true;
		
		if (status != GL.GL_FRAMEBUFFER_COMPLETE_EXT)
			throw new Exception("FBO Creation Error");
		//Get the openGL object (with context!)
		GL gl = GraphicsManager.getGL();
		
		//Create a valid handle to manage the frame buffer
		//this.intBuffer = IntBuffer.allocate(1);
		//gl.glGenFramebuffersEXT(1, this.intBuffer);
		gl.glGenFramebuffersEXT(1, ints, 0);
		this.fbo = ints[0]; 
		//this.fbo = this.intBuffer.get(0);
		
		//Bind the FBO
		gl.glBindFramebufferEXT(GL.GL_FRAMEBUFFER_EXT, this.fbo);
		
		//Create a depth buffer
		//this.intBuffer = IntBuffer.allocate(1);
		gl.glGenRenderbuffersEXT(1, ints, 1); //this.intBuffer);
		this.depthBuffer = ints[1];
		//this.depthBuffer = this.intBuffer.get(0);
		
		//Bind the render buffer
		gl.glBindRenderbufferEXT(GL.GL_RENDERBUFFER_EXT, this.depthBuffer);
		
		//Tell openGL how much storeage space we want for the render buffer
		gl.glRenderbufferStorageEXT(GL.GL_RENDERBUFFER_EXT, GL.GL_DEPTH_COMPONENT, width, height);
		
		//Now attach the render buffer to the FBO we created
		gl.glFramebufferRenderbufferEXT(GL.GL_FRAMEBUFFER_EXT, GL.GL_DEPTH_ATTACHMENT_EXT, GL.GL_RENDERBUFFER_EXT, this.depthBuffer);
		
		//Create a texture handle
		//this.intBuffer = IntBuffer.allocate(1);
		gl.glGenTextures(1, ints, 2); //this.intBuffer);
		this.color_texture = ints[2];
		//this.color_texture = this.intBuffer.get(0);
		
		//Bind the handle as a 2D texture
		gl.glBindTexture(GL.GL_TEXTURE_2D, this.color_texture);
		
		//Set texture parameters
		gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_LINEAR);
		gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_LINEAR);
		gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_S, GL.GL_CLAMP_TO_EDGE);
		gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_T, GL.GL_CLAMP_TO_EDGE);

		//Create a image of the same width and height as the render buffer
		gl.glTexImage2D(GL.GL_TEXTURE_2D, 0, GL.GL_RGBA8, width, height, 0, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, null);
		
		//Attach the colour texture to the FBO
		gl.glFramebufferTexture2DEXT(GL.GL_FRAMEBUFFER_EXT, GL.GL_COLOR_ATTACHMENT0_EXT, GL.GL_TEXTURE_2D, this.color_texture, 0);
		
		
		int status = gl.glCheckFramebufferStatusEXT(GL.GL_FRAMEBUFFER_EXT);
		
		this.active = true;
		
		if (status != GL.GL_FRAMEBUFFER_COMPLETE_EXT)
			throw new Exception("FBO Creation Error");

I have narrowed the line of code which caused the error to the third line; gl.glGenFramebuffersEXT(1, ints, 0);

I have a game logic thread running as well as a render thread. When I do not run the game logic thread the FBO is created without an issue. However stopping my logic thread to create FBO’s when I need them doesnt really lend itself to good game play.

The logic thread does no interact with the FBO class in any way so I am at a lost of why it is happening. Does anybody have a solution with does not involve either pausing my logic thread or creating all fbo’s at engine startup?

[GKW]

Does your logic thread access the “ints” variable? Possibly the logic thread is uninitializing that variable? There’s not much that can go wrong with that method.

[Phenix]

No, at no point does the logic thread even access the FBO class

[GKW]

So you are sure that the “ints” variable is created, initialized and is never modified by the logic thread? Does the logic thread make any GL calls at all? That’s just a little odd that the code works when the logic thread is paused but doesn’t work when it’s running, assuming that it doesn’t alter the “ints” variable in anyway.

[lhkbob]

@Phenix

I have a game logic thread running as well as a render thread. When I do not run the game logic thread the FBO is created without an issue. However stopping my logic thread to create FBO’s when I need them doesnt really lend itself to good game play.

I’m pretty sure you can keep fbo’s around for a while instead of creating a new one whenever you need it. Perhaps it’s better to initialize them once in the beginning – where you can stop the logic thread – and reuse any fbo id’s later on for effects.