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Index › Programming Questions & Help › Syntax Questions › Layering Objects / moving to front ?
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Layering Objects / moving to front ?? (Read 1050 times)
Evian_water
Layering Objects / moving to front ??
Apr 11th, 2009, 5:40am  
Hi Guys

I tried to find some topics on placing an elipse on top of a circle but i find that my elipse dissappears when i try and code it.

Are there any reserved words to help with this issue?

thanks
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Lasrin
Re: Layering Objects / moving to front ??
Reply #1 - Apr 11th, 2009, 5:46am  
which ever shape you draw last is the one on top.  If you want the ellipse to appear on the circle, change the order in which you draw them, or increase the ellipses size so it "sticks out".
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Lasrin Xefativ, Exiled Lord of Chaos
Devote' to the Platypus Messiah first order of the Skittle
Lasrin  
Evian_water
Re: Layering Objects / moving to front ??
Reply #2 - Apr 11th, 2009, 6:01am  
Lasrin wrote on Apr 11th, 2009, 5:46am:
which ever shape you draw last is the one on top.  If you want the ellipse to appear on the circle, change the order in which you draw them, or increase the ellipses size so it "sticks out".


Thats what should be happening but it is not happening, the last elipse is being placed behind the others infront of it.
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Evian_water
Re: Layering Objects / moving to front ??
Reply #3 - Apr 11th, 2009, 6:13am  
I am trying to place a Ellipse on top of a sphere. Is this why it is being displayed behind the sphere ??


size(400, 400, P3D);
noStroke();
sphereDetail(12);
lights();
background(0);

translate(200, 220, 200);
sphere(30);

translate(0, -40, 0);
sphere(20);

translate(0, -25, 0);
sphere(10);

fill(150);
ellipse(8,-5,10,10);
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Cedric
Re: Layering Objects / moving to front ??
Reply #4 - Apr 11th, 2009, 7:16am  
the problem is that all your objects are created at the same Z coordinate. That means, your ellipse is always created inside your spheres... one way would be to move the spheres into the background... Dont forget to use pushMatrix(); popMatrix(), so it doesnt affect your ellipse...

size(400, 400, P3D);
noStroke();
sphereDetail(12);
lights();
background(0);

pushMatrix();
translate(200, 220, -100);
sphere(30);

translate(0, -40, 0);
sphere(20);

translate(0, -25, 0);
sphere(10);
popMatrix();

fill(150);
ellipse(width/2,height/2,40,40);
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V
Re: Layering Objects / moving to front ??
Reply #5 - Apr 12th, 2009, 5:15am  
or disable depth testing.

hint(DISABLE_DEPTH_TEST);
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Victor Martins | www.pixelnerve.com/v
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Evian_water
Re: Layering Objects / moving to front ??
Reply #6 - Apr 17th, 2009, 2:27pm  
V wrote on Apr 12th, 2009, 5:15am:
or disable depth testing.

hint(DISABLE_DEPTH_TEST);


Hi

I tried to find information on this but i cannot find anything in the online refrence manual.
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V
Re: Layering Objects / moving to front ??
Reply #7 - Apr 17th, 2009, 2:34pm  
using the search field at the top of the page i got this:

http://processing.org/reference/hint_.html
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Victor Martins | www.pixelnerve.com/v
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Evian_water
Re: Layering Objects / moving to front ??
Reply #8 - Apr 17th, 2009, 5:30pm  
Cedric wrote on Apr 11th, 2009, 7:16am:
the problem is that all your objects are created at the same Z coordinate. That means, your ellipse is always created inside your spheres... one way would be to move the spheres into the background... Dont forget to use pushMatrix(); popMatrix(), so it doesnt affect your ellipse...

size(400, 400, P3D);
noStroke();
sphereDetail(12);
lights();
background(0);

pushMatrix();
translate(200, 220, -100);
sphere(30);

translate(0, -40, 0);
sphere(20);

translate(0, -25, 0);
sphere(10);
popMatrix();

fill(150);
ellipse(width/2,height/2,40,40);


Hi

I have been trying to find some sort of understanding of push and pop but i cant find anything that explains why i need to use them at all.  Cry

A google search yields nothing that explains it properly, and the online reference manual here says you should have knowledge of matrix stacks.
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Evian_water
Re: Layering Objects / moving to front ??
Reply #9 - Apr 17th, 2009, 5:36pm  
V wrote on Apr 17th, 2009, 2:34pm:
using the search field at the top of the page i got this:

http://processing.org/reference/hint_.html


I must seem really silly but i did look earlier and didnt see that on the reference. I even sorted it a-z aswell how embarrasing  Grin

Thank you though, it makes me wonder what the point is in using pus and pop matrix if u can use this instead. Much easier.
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Cedric
Re: Layering Objects / moving to front ??
Reply #10 - Apr 17th, 2009, 5:42pm  
Quote:
Thank you though, it makes me wonder what the point is in using pus and pop matrix if u can use this instead. Much easier.



it is Smiley
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V
Re: Layering Objects / moving to front ??
Reply #11 - Apr 17th, 2009, 6:26pm  
disabling the depth test means that it rejects no pixel, so it depends on the order you render. u can draw an object that is at a longer distance than another and still have it rendered on top. because it wasnt discarded by the z-testing.

as for push/pop. yes you should read about matrix stacks.
basically it saves a copy of your current matrix (push) so you can do other transformations and get back to the point you were (pop).

just do some tests rendering with push/pop and without it. you will get to it.
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