LCD Monitor
BlitzMax Forums/BlitzMax Beginners Area/LCD Monitor
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| Has anyone ever compared using an LCD to a CRT. It seems that when I hook up my LCD programs seem to jump. almost like the timing is off. Can this be sometime to do with the monitor. I even tried Digesteroids in the Samples folder and it was also jumpy and slow. Any Idea or suggestions? It's Gateway 21". http://www.circuitcity.com/ssm/Gateway-Monitor-FPD2185W-/sem/rpsm/oid/138525/rpem/ccd/productDetail.do Sweet Picture and features. But I mainly use it for programming and if I can't get it right it's going back to the store. ERic |
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| tft monitors usually need 60fps to be smooth, any higher or lower and it looks jumpy. |
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| Most likley cause: You have a Hz parameter specified in your Graphics call, and it does not match the refreshrate of your monitor. Doing so will cause things to be choppy... |
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| Listen to xlsior, and install the proper drivers :P - 75htz pwns!!! |
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| Also, the way that two twpes of monitors work is very diffrent. CRT nonitors use a scan line system while LCD use what is alled "Random Refresh" In other words, your CRT udpates the entire screen every vertical sysn, so if your at 60Hz then the image will be redrawn 60 times a second. By incleasing this to a higher number we can reduce flicker. On the other hand...... LCD monitors only updates the portion of the screen that has changed (its delta) so thats why they call it random refresh. Instead if it redrawing the image evey Hz - it CHECKS to see if there have been any changes since the last update - so an LCD monitor may update a few pixels, a bunch or even none at all depeding on what the screen status is. Many people assume that a higher refresh rate is better for LCD screens as well as CRT's - its not - becase of the diffrent ways they work, increasing the refresh rate of the LCD monitor can CAUSE flicker as the LCD attemps to keep up with the changes at an ever faster rate and LCD is slower than phospher in CRT's. The four things you can do to minimize flicker on an LCD monitor are: 1) Check to make sure that the graphics mode you are using is the "prefered" or Natice mode of the monitor. Some lower end LCD screens do their Standard res jst fine, but if you switch to say 640 x 480 can be confused - or may not even display at all. Blitz 3D has a major problem with this if you dont let the user select the graphics mode you can und with with a very bad display on some LCD monitors with no way to adjust it! 2) Keep you screen refresh rate at a reasonable level - 60Hz for an LCD is ususaly fine. If you have your set to 80 or 120 - lower it back down! 3) Make sure your progams Select the correct graphics mode and refresh rate to match your system hardware. 4) When updating graphics do so on a vertical sync pulse, this will make a smooth motion on CRT's and LCD's as well. To add thios function is as simple as adding a command to your program. I know in Blitz 3d the command is VWAIT, Blitx max has a similar type of thing but I'm drawing a blank (screen blank?) as to what it is at the moment. Good luck Dr. Wildrick |
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| Anyone know the Vsync command for Bmax?? Or is there one? |
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| Ok,here is how to Sync with your vertical refresh in B MAx Change your commds of: Flip to Flip(1) That will flip the back buffer on a vertical sync pulase All the best Dr. Wildrick |
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| Thanks Dr. Wildrick! |
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On my LCD GraphicsHertz()Reports 0. Nothing I do allows me to get the Refresh rate. Is there anyone else that can duplicate this? Eric |
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| GraphicsHertz() does not work in DirectX mode. It's OK in OpenGL, but not in DirectX. Posted this as a bug a number of months ago when the GraphicsHertz() command was firest introduced, but got no response. Maybe due for a re-post? Before the GraphicsHertz() was added, there was a GetGraphics() command that retrieved several of the graphic parameters including the refreshrate -- so it did work in DX mode... But when that command was removed and replaced with several stand-alone ones, this ability broke. Major inconvenience, since I did depend on it for some timing issues in the game I was working on at the time. |
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| the Hertz is very instable anyway. I would never use it on the graphics call as it breaks with "unsupported bla" on my notebook whenever I specify it other than 0. |
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| the Hertz is very instable anyway. I would never use it on the graphics call as it breaks with "unsupported bla" on my notebook whenever I specify it other than 0. Just out of curiosity: If you use countgraphicsmode/getgraphicsmode to enumerate your available resolutions, does it list the availabe screenmodes with their respective refresh rates there? |
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| Yes It does report all of the screen modes and I just confirmed what you said that GL GraphicHertz() works but DX does not. Regards, ERic |
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| It shouldnt really matter as every tft i've seen only supports 2 refresh rates anyway, 75hz using dsub and 60hz using dvi. |
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| It shoul;dn't really matter as every tft I've seen only supports 2 refresh rates anyway, 75Hz using dsub and 60hz using dvi I can run mine over DSUB using a 60, 72 or 75Hz refreshrate, and I've seen others do the same... But if your statement were true, it would have been an even bigger issue if people count on a high refreshrate being available. (since pretty much any video card will do 85/100/100+ Hz as well) |
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| Before the GraphicsHertz() was added, there was a GetGraphics() command that retrieved several of the graphic parameters including the refreshrate -- so it did work in DX mode... But when that command was removed and replaced with several stand-alone ones, this ability broke. The command for grabbing all parameters is GetGraphicsMode, which is still available. However, I find that on my Mac laptop the hertz setting comes back as zero. Works fine under Windows and Linux no matter whether I use DirectX or OpenGL. Seems to be the opposite of what everyone else is experiencing! |
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| Just to point out my DVI TFT runs at 75hz, thanks. |
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| Mine also runs at 75HZ DVI Input. |
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| My laptop runs at 60Hz and is jerky. |
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| mine might be limited to 60hz dvi cos its 20" :( |
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| I doubt it. Plenty of 24" and above monitors with 75hz. It's an individual specification, not a rule about *anything*. |
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| Yeah Mine is 21" and is at 75HZ 1680 x 1050 |
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