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Index › Programming Questions & Help › OpenGL and 3D Libraries › Problem with hint(DISABLE_DEPTH_TEST)
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Problem with hint(DISABLE_DEPTH_TEST) (Read 712 times)
justind
Problem with hint(DISABLE_DEPTH_TEST)
Jun 13th, 2008, 5:24pm  
Hello,

I'm trying to to use hint(DISABLE_DEPTH_TEST) to draw directly to the screen, however it's not having any effect unless I call camera() before it, which messes up how my sketch looks. The text I'm trying to draw on the screen appears in the model.

A few details:
I'm using OPENGL, and the Obsessive Camera Direction library with Processing 133. I'm on a Mac G5 with a discrete graphics card. My code looks like this:

MyPApplet.hint(PApplet.DISABLE_DEPTH_TEST);
MyPApplet.fill(255);
MyPApplet.textSize(15f);
MyPApplet.text(mousepos, 10, 10);

MyPApplet.unhint(PApplet.DISABLE_DEPTH_TEST);

(Note that I'm calling this in the draw function of a class: MyPApplet refers to my processing applet.)

Could this be a problem with using the OCD library? Any ideas? Thanks.
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a_g
Re: Problem with hint(DISABLE_DEPTH_TEST)
Reply #1 - Jun 19th, 2008, 11:04am  
If I remember correctly you need to reset the camera for the things to stick to your screen and not be placed "in the world" so to speak.

What I did for my simple 3dengine was this, just before writing the gui elements.

   ((PGraphicsOpenGL)g).gl.glClear(GL.GL_DEPTH_BUFFER_BIT);
   camera();

How are you using OCD in your program?
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justind
Re: Problem with hint(DISABLE_DEPTH_TEST)
Reply #2 - Jun 19th, 2008, 9:20pm  
Well, with a bit of toying around, I got this working. It seems like a bit of a hack, but it works smoothly enough in my initial tests:

// Store your OCD camera's position and target in variables. I'm not showing it here, but I have them as Vec3D objects (Toxi's Library).

// Reset the camera
camera();
// Disable Depth Test
hint(DISABLE_DEPTH_TEST);
// Do your thing
fill(255);
rect(width/2, height/2, 30,30);
// Enable Depth Test
unhint(DISABLE_DEPTH_TEST);
// Set the camera to where you had it.
camera(position.x, position.y, position.z,  target.x, target.y, target.z, 0, 1, 0);

This works even if you change the OCD camera's FOV, which I can't explain. If someone has a better way to do this, please post.
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justind
Re: Problem with hint(DISABLE_DEPTH_TEST)
Reply #3 - Jun 23rd, 2008, 7:08pm  
Well, I didn't test this well enough. It's drawing my rect where it should be on the screen, but behind everything else. Anyone have any ideas?
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