Comments on: 7. OpenGL Rotation and Translation (Version 2.0) http://www.swiftless.com/tutorials/opengl/rotation.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: LWJGL help please http://www.swiftless.com/tutorials/opengl/rotation.html/comment-page-1#comment-3923 LWJGL help please Tue, 27 Dec 2011 07:09:56 +0000 http://swiftless.com/wordpress/?p=113#comment-3923 [...] {ord=Math.random()*10000000000000000;}document.write(''); Try reading this: 7. OpenGL Rotation and Translation (Version 2.0) | Swiftless Tutorials You need to really get your head around keeping track of rotations and translations. [...] [...] {ord=Math.random()*10000000000000000;}document.write(''); Try reading this: 7. OpenGL Rotation and Translation (Version 2.0) | Swiftless Tutorials You need to really get your head around keeping track of rotations and translations. [...]

]]> By: TeXiCiTy http://www.swiftless.com/tutorials/opengl/rotation.html/comment-page-1#comment-3411 TeXiCiTy Tue, 29 Nov 2011 19:15:19 +0000 http://swiftless.com/wordpress/?p=113#comment-3411 When using freeGLUT and GLEW I need to add glutPostRedisplay(); somewhere to make the mainloop actually loop and not freeze until there is a mouse click. Very strange but I had the same problem before when I first did this tutorial last year. When using freeGLUT and GLEW I need to add glutPostRedisplay(); somewhere to make the mainloop actually loop and not freeze until there is a mouse click. Very strange but I had the same problem before when I first did this tutorial last year.

]]> By: Garrison http://www.swiftless.com/tutorials/opengl/rotation.html/comment-page-1#comment-1998 Garrison Thu, 28 Jul 2011 21:28:06 +0000 http://swiftless.com/wordpress/?p=113#comment-1998 Ahha, I figured it by myself, cuz the yRotationAngle I set was 0.005f as what ur code shows, but it seems too slow to be recognized. So i changed it to 1.0f, and it starts to rotate faster. But seems all other ppl are doing good in 0.005f. So is this because of my computer is too slow or something? I bought it 2 years ago, don't think it's older than ur tutorial :-) Anyway, everything runs well so far. Great tutorial! Ahha, I figured it by myself, cuz the yRotationAngle I set was 0.005f as what ur code shows, but it seems too slow to be recognized. So i changed it to 1.0f, and it starts to rotate faster. But seems all other ppl are doing good in 0.005f. So is this because of my computer is too slow or something? I bought it 2 years ago, don’t think it’s older than ur tutorial :-) Anyway, everything runs well so far.
Great tutorial!

]]> By: Garrison http://www.swiftless.com/tutorials/opengl/rotation.html/comment-page-1#comment-1997 Garrison Thu, 28 Jul 2011 21:21:20 +0000 http://swiftless.com/wordpress/?p=113#comment-1997 hi, I just have exactly the same code, but the shape doens't do any rotation and translate. It seems the frame is automatically updating forever, so the shape is flashing( along with the display() 's updating ) . Can u explain this for me please? hi, I just have exactly the same code, but the shape doens’t do any rotation and translate. It seems the frame is automatically updating forever, so the shape is flashing( along with the display() ‘s updating ) . Can u explain this for me please?

]]> By: zaqi http://www.swiftless.com/tutorials/opengl/rotation.html/comment-page-1#comment-1782 zaqi Thu, 16 Jun 2011 06:45:31 +0000 http://swiftless.com/wordpress/?p=113#comment-1782 how to change the translation & rotation? so i can translation anywhere and rotatin any axis example like the earth rotates around the sun thanks before how to change the translation & rotation?
so i can translation anywhere and rotatin any axis
example like the earth rotates around the sun
thanks before

]]> By: zaqi http://www.swiftless.com/tutorials/opengl/rotation.html/comment-page-1#comment-1781 zaqi Thu, 16 Jun 2011 04:32:13 +0000 http://swiftless.com/wordpress/?p=113#comment-1781 How set the speed of translation? because the translation for the example above is too fast thanks b4 How set the speed of translation?
because the translation for the example above is too fast
thanks b4

]]> By: Swiftless http://www.swiftless.com/tutorials/opengl/rotation.html/comment-page-1#comment-1604 Swiftless Sun, 17 Apr 2011 03:42:26 +0000 http://swiftless.com/wordpress/?p=113#comment-1604 Hi Rahul, While it is possible to work it out mathematically, I just did it by hand. To work it out, you need the field of view, the near and far clipping planes and the z axis of the object. There is plenty of information online about perspective projections, especially in some ray tracer tutorials. Cheers, Swiftless Hi Rahul,

While it is possible to work it out mathematically, I just did it by hand.

To work it out, you need the field of view, the near and far clipping planes and the z axis of the object. There is plenty of information online about perspective projections, especially in some ray tracer tutorials.

Cheers,
Swiftless

]]> By: Rahul http://www.swiftless.com/tutorials/opengl/rotation.html/comment-page-1#comment-1596 Rahul Sat, 09 Apr 2011 19:49:28 +0000 http://swiftless.com/wordpress/?p=113#comment-1596 hi!! I'm beginner in Open Gl and your program helped a lot... Can you pls explain how did u figure out the limit of y axis.. i.e why it has to be between -3 to 3.... How did u get this 3?? Thank you.. hi!!
I’m beginner in Open Gl and your program helped a lot…
Can you pls explain how did u figure out the limit of y axis.. i.e why it has to be between -3 to 3…. How did u get this 3??
Thank you..

]]> By: oldnewbie http://www.swiftless.com/tutorials/opengl/rotation.html/comment-page-1#comment-1561 oldnewbie Sat, 12 Mar 2011 22:24:10 +0000 http://swiftless.com/wordpress/?p=113#comment-1561 Hi. Can you suggest a (preferably freeware) software to save opengl screen as video?Do these kind of softwares have a general name? Hi.
Can you suggest a (preferably freeware) software to save opengl screen as video?Do these kind of softwares have a general name?

]]> By: Swiftless http://www.swiftless.com/tutorials/opengl/rotation.html/comment-page-1#comment-1325 Swiftless Thu, 16 Dec 2010 01:59:54 +0000 http://swiftless.com/wordpress/?p=113#comment-1325 Hi MatMar, While you have a valid point that the human brain won't notice a difference with framrates above approx. 24 fps, there is a subconscious interaction with the brain. I believe it was the movie Fight Club where a 25th frame was added every now and then with a picture of Bambi and people would suddenly burst into tears. Films have actual blur recorded from fast movement of a camera, it's a natural effect just as chromatic abberation or depth of field. Which requires faking in a virtual scene. However stating it is completely pointless to render above screen refresh rate is extremely misinformed. Maybe not from a rendering perspective unless you want extremely high quality motion blur that spans more than 60 frames, plus many rendering techniques require multiple passes. But definitely from an input and algorithmic point of view. Many algorithms can be optimized by spreading them over several frames, a clear example of this is sorting, where you sort a set of data over time and get a more accurate result each time. Sorting is a major issue in computer graphics, how else do you render translucent objects correctly? Or perform correct culling? The faster you do this, the more accurate the result each visible frame. Then you have the input point of view, where compared to a 30fps scene, a games running at 60fps has twice the accuracy with a mouse. This point alone is a major factor in competitive gaming. Therefore if you are running at 120fps and your mouse input is linked to your rendering, you're going to get double the accuracy and responsiveness again. You can offload input to another thread or even another core, but you still have to sync the two and you will get higher responsiveness in your scene. These are just two examples. Try to add in physics calculations, audio, artificial intelligence or anything else you need to put in your application, when you still need it to run at, at least 60fps. Cheers, Swiftless Hi MatMar,

While you have a valid point that the human brain won’t notice a difference with framrates above approx. 24 fps, there is a subconscious interaction with the brain. I believe it was the movie Fight Club where a 25th frame was added every now and then with a picture of Bambi and people would suddenly burst into tears.

Films have actual blur recorded from fast movement of a camera, it’s a natural effect just as chromatic abberation or depth of field. Which requires faking in a virtual scene.

However stating it is completely pointless to render above screen refresh rate is extremely misinformed. Maybe not from a rendering perspective unless you want extremely high quality motion blur that spans more than 60 frames, plus many rendering techniques require multiple passes. But definitely from an input and algorithmic point of view. Many algorithms can be optimized by spreading them over several frames, a clear example of this is sorting, where you sort a set of data over time and get a more accurate result each time. Sorting is a major issue in computer graphics, how else do you render translucent objects correctly? Or perform correct culling? The faster you do this, the more accurate the result each visible frame.

Then you have the input point of view, where compared to a 30fps scene, a games running at 60fps has twice the accuracy with a mouse. This point alone is a major factor in competitive gaming. Therefore if you are running at 120fps and your mouse input is linked to your rendering, you’re going to get double the accuracy and responsiveness again. You can offload input to another thread or even another core, but you still have to sync the two and you will get higher responsiveness in your scene.

These are just two examples. Try to add in physics calculations, audio, artificial intelligence or anything else you need to put in your application, when you still need it to run at, at least 60fps.

Cheers,
Swiftless

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