Comments on: 18. OpenGL Popping and Pushing Matrices http://www.swiftless.com/tutorials/opengl/pop_and_push_matrices.html Game Programming and Computer Graphics Tutorials Wed, 01 Feb 2012 09:19:36 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: kropcke http://www.swiftless.com/tutorials/opengl/pop_and_push_matrices.html/comment-page-1#comment-3082 kropcke Sun, 13 Nov 2011 05:41:29 +0000 http://swiftless.com/wordpress/?p=181#comment-3082 Very, very big fan of your tutorials Swiftless. Thank you again. They are terrific. -kropcke Very, very big fan of your tutorials Swiftless.
Thank you again. They are terrific.

-kropcke

]]> By: Swiftless http://www.swiftless.com/tutorials/opengl/pop_and_push_matrices.html/comment-page-1#comment-1607 Swiftless Sun, 17 Apr 2011 03:50:18 +0000 http://swiftless.com/wordpress/?p=181#comment-1607 Hi Theo, The way matrices work in OpenGL, are based on a Stack setup. You start off with a matrix on the stack called the "Transformation Matrix" (there are also ones for textures and the projection), every time you do a call to glTranslate or glRotate, this changes the "Transformation Matrix". If you call glPushMatrix, it takes an exact duplicate of the current "Transformation Matrix" and puts this on the top of the stack and this becomes the current matrix for all further glTranslate or glRotate calls. You can nest as many of these as you like within each other. Then once you call glPopMatrix, it pops the current "Transformation Matrix" off the stack and forgets it, and the previous "Transformation Matrix" becomes the current. I hope this helps a little. Cheers, Swiftless Hi Theo,

The way matrices work in OpenGL, are based on a Stack setup.

You start off with a matrix on the stack called the “Transformation Matrix” (there are also ones for textures and the projection), every time you do a call to glTranslate or glRotate, this changes the “Transformation Matrix”. If you call glPushMatrix, it takes an exact duplicate of the current “Transformation Matrix” and puts this on the top of the stack and this becomes the current matrix for all further glTranslate or glRotate calls. You can nest as many of these as you like within each other. Then once you call glPopMatrix, it pops the current “Transformation Matrix” off the stack and forgets it, and the previous “Transformation Matrix” becomes the current.

I hope this helps a little.
Cheers,
Swiftless

]]> By: Theo http://www.swiftless.com/tutorials/opengl/pop_and_push_matrices.html/comment-page-1#comment-1592 Theo Fri, 01 Apr 2011 00:09:22 +0000 http://swiftless.com/wordpress/?p=181#comment-1592 I get how to use them, but about how they work: Does it add and subtract the matrices, or does it store on Push, and reset to identity, then transform to stored position / orientation? And can you have nested Push/Pops? ex: push() translate push() draw pop() pop() push() rotate push() draw pop() push() draw pop() pop() I get how to use them, but about how they work: Does it add and subtract the matrices, or does it store on Push, and reset to identity, then transform to stored position / orientation? And can you have nested Push/Pops? ex:
push()
translate
push()
draw
pop()
pop()
push()
rotate
push()
draw
pop()
push()
draw
pop()
pop()

]]> By: freezway http://www.swiftless.com/tutorials/opengl/pop_and_push_matrices.html/comment-page-1#comment-849 freezway Sat, 17 Jul 2010 03:57:55 +0000 http://swiftless.com/wordpress/?p=181#comment-849 =| thanks for trying to explain, but im still lost. Don't feel bad, 4 people ahve tried to explain it to me... I am still clueless... you should be on ##opengl on freenode =| thanks for trying to explain, but im still lost. Don’t feel bad, 4 people ahve tried to explain it to me… I am still clueless… you should be on ##opengl on freenode

]]> By: Swiftless http://www.swiftless.com/tutorials/opengl/pop_and_push_matrices.html/comment-page-1#comment-769 Swiftless Wed, 02 Jun 2010 00:39:27 +0000 http://swiftless.com/wordpress/?p=181#comment-769 It should be up now sorry, I have had a few posts suddenly stop showing, but I think I have fixed them all now. Cheers, Swiftless It should be up now sorry, I have had a few posts suddenly stop showing, but I think I have fixed them all now.

Cheers,
Swiftless

]]> By: John http://www.swiftless.com/tutorials/opengl/pop_and_push_matrices.html/comment-page-1#comment-768 John Tue, 01 Jun 2010 23:49:08 +0000 http://swiftless.com/wordpress/?p=181#comment-768 Is this article not done yet? I don't see anything. Is this article not done yet? I don’t see anything.

]]> By: orthogonal projections http://www.swiftless.com/tutorials/opengl/pop_and_push_matrices.html/comment-page-1#comment-301 orthogonal projections Mon, 05 Apr 2010 16:08:15 +0000 http://swiftless.com/wordpress/?p=181#comment-301 [...] projections 18. OpenGL Popping and Pushing Matrices | SwiftlessWhen drawing objects in OpenGL, it can be annoying that you do a translation, and then before [...] [...] projections 18. OpenGL Popping and Pushing Matrices | SwiftlessWhen drawing objects in OpenGL, it can be annoying that you do a translation, and then before [...]

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