http://www.opengl.org/discussion_boards/ en Wed, 22 May 2013 16:26:21 GMT vBulletin 60 http://www.opengl.org/discussion_boards/images/misc/rss.png http://www.opengl.org/discussion_boards/ http://www.opengl.org/discussion_boards/showthread.php/181731-how-to-read-frames-from-the-video-with-opengl?goto=newpost Sun, 19 May 2013 13:58:40 GMT I'm a beginner to opengl and I want to read frames from a video file, process them ( eliminate the noise) and then display them on a monitor at 120hz. I don't know how to read frames with opengl. Could someone give me a hand?
I'm now trying solving it in a silly way: use opencv to read frames into a Iplimage* data and then try converting "Iplimage*" to "Iluint" type. I'm wondering whether this works and if so, how to convert?
Thanks.:D ]]> sheny35 http://www.opengl.org/discussion_boards/showthread.php/181731-how-to-read-frames-from-the-video-with-opengl http://www.opengl.org/discussion_boards/showthread.php/181679-Calculating-all-pixels-in-a-frame?goto=newpost Sat, 11 May 2013 20:55:09 GMT Hy,
I didn't know if this is the right forum or the right category to post this thread, so please move this thread if necessary, or point me to a more relevant forum.
Anyway, here is my question:

I was doeing some research on computer graphics. I want to build a system that can render frames and display them. Herefor I made an 2D array which acts as a buffer. This way I can fill up all the pixels and afterwards display the right color data.

But here is my problem: Filling the buffer requires a double for-loop over 800x600 pixels. And this is takes an enormous amount of time. This is actually not that strange since we're speaking of 480000 pixels. But that's when I started wondering how this is done in current technologies. Because somehow a game, or application, even the OS is capable of refreshing the window at a framerate of 60Hz. On a fullHD screen this means calculating 124.416.000 pixels in one second, or about 8 nanoseconds per pixel. This seams to me as an enormouse speed, as this about the speed of a modern processor.

I've been thinking about it and I can't seem to figure it out, my possible explenations:

GPU parallel programming:

As a GPU can execute many tasks at the same time, each pixel could be calculated in a thread. This would give an enourmous speed boost. But computers didn't have always GPU's and parallel programming is quite new. So how was this done before this?

partial refresh:

I somehow the computer could predict which pixels need refresh and which can stay the same, we could limit calculations to the new pixel values. This would help, but it's clear that this is not the solution. A movie sequence with new pixels every frame can be displayed perfectly.

pixel calculations:

If the calculations for the color of a pixel could be simplified, it would increase the speed of the entire process significantly. But in my program, I had a method called pixel_calculation. And in my current implementation it just returns a constant value. So no calculations are done, and this seems to me the fastest you can get, and yet still it is incredibly slow.

These were the options I could come up with, but at the same time, I could easily counter them. I've been struggeling with this for a long time now. Can anyone explain to me how the color value of every pixel is calculated in such a high speed?

Thanks for the help ]]> genzm19 http://www.opengl.org/discussion_boards/showthread.php/181679-Calculating-all-pixels-in-a-frame http://www.opengl.org/discussion_boards/showthread.php/181670-OpenGL-for-Gaming?goto=newpost Fri, 10 May 2013 14:01:46 GMT Hi guys,

I'd like to make a game using OpenGL, but just wanted to ask if it's worth doing so or should I just stick to programs like Flash.

Thanks ]]> Out Of League http://www.opengl.org/discussion_boards/showthread.php/181670-OpenGL-for-Gaming http://www.opengl.org/discussion_boards/showthread.php/181669-Backwards-Compatibility?goto=newpost Fri, 10 May 2013 12:14:35 GMT Is OpenGL verison 4.2 backwards compatible with version 2.0? Is OpenGL verison 4.2 backwards compatible with version 2.0? ]]> nelsonf1906 http://www.opengl.org/discussion_boards/showthread.php/181669-Backwards-Compatibility http://www.opengl.org/discussion_boards/showthread.php/181657-Poser-and-the-Firepro-V3900-graphics-card?goto=newpost Thu, 09 May 2013 00:23:01 GMT I asked this question in the OpenGL Drivers section but was told that this one was probably more appropriate. So let me try it here. I... I asked this question in the OpenGL Drivers section but was told that this one was probably more appropriate. So let me try it here.

I recently purchased a FirePro V3900 card specifically to use with Poser. My previous card worked fine but got fried.

I am finding that with this card the Preview window frequently hangs when in OpenGL mode. Sometimes when I try to move the camera nothing happens, but sometimes part of the window responds to the camera movement and part doesn't. After much experimentation I have figured out how to replicate the problem:

1. Place a second window (e.g Library window) over the Preview window.
2. Move the second window just a bit.
3. Rotate the camera. Once you move the second window out of the way you can see that the part of the Preview window behind the second window had moved as it should, but the visible part had not.

I have updated the drivers several times and have cleaned out the registry of any orphaned driver settings.

I have posted this issue to the technical support staffs at both AMD and Smith Micro (Poser), but they seemed to be stumped. I am hoping you folks might have some ideas.

My OS is Windows Vista Business 32-bit Service Pack 2. The device driver for the card is version 8.982.8.3000 released on 9/30/2012. I've also tried this with version 9.3.3.3000 released 2/6/2013 with the same results.

Thanks for any help you can give me. ]]> ElZagna http://www.opengl.org/discussion_boards/showthread.php/181657-Poser-and-the-Firepro-V3900-graphics-card http://www.opengl.org/discussion_boards/showthread.php/181568-I-need-help-upgrading-OpenGl?goto=newpost Sat, 27 Apr 2013 19:25:10 GMT Hi, i have some days trying to upgrade my version of OpenGl. I readed a lot about it, and it sayd if i upgrade the drivers of my Graphic card, the... Hi, i have some days trying to upgrade my version of OpenGl. I readed a lot about it, and it sayd if i upgrade the drivers of my Graphic card, the opengl will update too. I talked with Lenovo and Intel to search drivers for my actual graphic card, they told me there are not drivers for my OS and My Graphic card model (Windows xp Professional and Mobile Intel (r) 965 express chipset family). I want to know if there is a way to upgrade the OpenGl library without updating the graphic card drivers. I am trying to play Minecraft, and i cant play it until i update the OpenGl Library.

Thanks. ]]> MiguelCh http://www.opengl.org/discussion_boards/showthread.php/181568-I-need-help-upgrading-OpenGl