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Submitted by George Ziniewicz, posted on May 13, 2001




Image Description, by George Ziniewicz



This is a screen of a recent OpenGL app I wrote for the OpenGL Challenge.

Nothing that special (a joyriding simulation), but curious is a round noisy lightmap I added over the scene when I was done with a frame. The noise is procedurally generated about 20 x a second (I run around 100 fps on a GeForce2), rides atop a fixed noise value per line, and a cone, providing an effect of an "old-time" television: noise, discrete horizontal line noise for a slight banding effect, and corner vignetting.

The effect is better when viewed animated:

http://zintel.com/apps/HiwayZ.zip

The OpenGL Challenge site has it w/ source: http://OGLChallenge.OTri.net/. The effect can be toggled (key "i"), noise level adjusted (), and size adjusted ([]). Or try for a popup menu, and select "Options", there are plenty of adjustors.

Also of note in the app is a retro 3-2-1 intro, and a closing screen "splintering" effect, which does 255 variations of "chop the screen into bits and move them". Toggle key "x" to demo.

zin


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Archive Notice: This thread is old and no longer active. It is here for reference purposes. This thread was created on an older version of the flipcode forums, before the site closed in 2005. Please keep that in mind as you view this thread, as many of the topics and opinions may be outdated.
 
Nilientes

May 13, 2001, 04:50 PM

hey i am first...
nice sreenie..
how do you do your sky??

 
Vorteks

May 13, 2001, 05:19 PM

Nice landscape, if a bit plain. I like the "tv" effect.

 
Wouter

May 13, 2001, 06:36 PM

Very nice, gives a real sense of speed. What would you say contributes to its sense of speed? the viewpoint close the ground? the smooth camera movement? a high FOV I bet?

btw why didn't you make the camera look left/right with the direction of the road (you do make it go up/down), that would feel even more realistic? maybe a bit of roll in there too? :)

oh, and this needs a recent version of glut, I got it complaining about a missing function initially.

 
iMalc

May 13, 2001, 09:12 PM

This picture looks slightly odd... is the water higher than some of the land???

Nice sky.

The corner darkening is done well. I tried that myself a while back in my software renderer.

btw, what's your poly count?

 
Mattman

May 14, 2001, 12:34 AM

I was thinking the water looked higher than the land too...

 
flure

May 14, 2001, 05:02 AM

yes, it seems that the water is higher than the ground ...

well, nevermind !

george is talking to us about his 'screen effect' which seems to be quite nice (can't see it at work, cause my vidcard suxx (only 2Mb VRAM))

and the screenshot is nice also ...

 
AndersO

May 14, 2001, 07:00 AM


It could be a hiway in Holland.


The noise kinda look cool. Aah, the motionsickness, joy!. :)

 
DennisM

May 14, 2001, 08:43 AM

It's not a highway in Holland, if it was the sky would be gray.

 
flure

May 14, 2001, 08:50 AM

herrm well last year i went in holland (eindhoven) and it was very sunny !!! :)

(also eindhoven is a very cute town)

 
DennisM

May 14, 2001, 09:37 AM

Maybe, but most of the time the weather sucks so I wouldn't call it a dutch highway :)

 
George Ziniewicz

May 14, 2001, 09:44 AM

My first Terragen sky at 256x256. I wish I could make it 360 degrees, Terragen seems to always draw a dark bottom when w/o a landscape.

 
George Ziniewicz

May 14, 2001, 09:48 AM

Yes, I was stuck with trying to update/port an old Mac app, and didn't want to deviate too far from the original.

 
George Ziniewicz

May 14, 2001, 09:52 AM

What would you say contributes to its sense of speed?

I accelerate on the downhills.


the viewpoint close the ground?

Could be, adjust with Up/Down Arrows.


the smooth camera movement? a high FOV I bet?

It all helps!


btw why didn't you make the camera look left/right with the direction of the road

I wanted you to be able to look around like when in a car. I did control heading by the road but didn't like it as mach.



maybe a bit of roll in there too? :)

Now that would be silly.



oh, and this needs a recent version of glut, I got it complaining about a missing function initially.

I have not upgraded my glut yet, should I? Any compatibility issues?

 
sagacity

May 14, 2001, 09:57 AM

Takeover2000, eh?

 
George Ziniewicz

May 14, 2001, 09:58 AM

This picture looks slightly odd... is the water higher than some of the land???

It could be! Ever been to Amsterdam? Switzerland? VirtuaLand? (*>*)



The corner darkening is done well. I tried that myself a while back in my software renderer.

Just a noisy cone really.



btw, what's your poly count?

There are 200 horizontal strips, each w/ 5 quads. Multipassed, thats only ~2,000.
Plus the sun, the lightmap quad, and a possible screen-fading quad.

 
George Ziniewicz

May 14, 2001, 10:04 AM

yes, it seems that the water is higher than the ground ...

I can swim.


well, nevermind !

Doesn't matter!



george is talking to us about his 'screen effect' which seems to be quite nice (can't see it at work,
cause my vidcard suxx (only 2Mb VRAM))

I am using an older glut (3.6?) but my GeForce2 has no trouble.
I do find OpenGL buggy, can't run many times w/o rebooting eventually, both with my apps and FPS, on both Mac & PC.



and the screenshot is nice also ...

thanx, actually the shot was taken just before I added in the TV "line" noise (after seeing a lousy video feed fron the Int'l space station).

 
flure

May 14, 2001, 10:28 AM

LOL !

so that's why it was so difficult to me to see the screen effect !! :)))))

 
flure

May 14, 2001, 10:30 AM

herm yeah, right :)

i should have thought that someone would guess that :)

 
George Ziniewicz

May 14, 2001, 11:02 AM

Aah, the motionsickness, joy!. :)


The coffeeshops in Amsterdam should help with that!

zin

 
EGreg

May 14, 2001, 01:00 PM

what is that "road" type thing on the ground? I didn't run the demo.

-Greg

 
Moby Disk

May 14, 2001, 01:18 PM

No issues. Get it. Everything wants it now.

 
Moby Disk

May 14, 2001, 01:21 PM

Me too! I thought maybe the JPG quality lost it.

 
Moby Disk

May 14, 2001, 01:22 PM

Yea, what about that "sky" and "ground" thing too?

 
George Ziniewicz

May 14, 2001, 01:39 PM

No no.

The IOTD screenshot posted has vignette and noise (15%), but scattered uniformly in x/y.

Then I saw that lousy video feed from the space station, and it had whole raster lines varying in light level, in addition to the random pixel noise.

This was an effect even more reminiscent of old tv, so I added it into my procedural generator in HiwayZ, but did not update the posted IOTD.

I notice that the jpg synthesized some line-oriented noise anyway! }B^)

 
lxnyce

May 14, 2001, 01:50 PM

This woudl make one great screen saver. Good work.

 
George Ziniewicz

May 14, 2001, 02:04 PM

> what is that "road" type thing on the ground? I didn't run the demo.

The app generates a continuously scrolling landscape, coming at the camera.

The camera rides (speeding up on the downgrades) over a road that moves left/right and up/down according to a double sin function on independent randomly moving counters.

Same for the grass field edge, and water's edge. The water texture is also scrolled.


First a sun rotates in a rotating starfield, or the skybox slowly rotates.

Then 200 strips (in a circular array) of 5 quads are rendered: grass, dirt, road, dirt, water.

Then the whole landscape is rendered again but with a scrolling cloud texture blended atop the first pass.

Then the entire screen is overlaid by the noisy vignette lightmap.

 
George Ziniewicz

May 14, 2001, 02:08 PM

> Yea, what about that "sky" and "ground" thing too?

Just patterns of color, light and dark, on a visual field.

Buddha says "What?" }B^)

 
George Ziniewicz

May 14, 2001, 02:10 PM

> This woudl make one great screen saver. Good work.

Thank you.

Is there a pc screensaver like one I had on my Mac (there were several), which can point to and run any app as a screensaver, unmodified?

zin

 
Evil Bill

May 14, 2001, 04:17 PM

I really like the cloud shadowing bit, although i think it looks better without the TV noise. Just personal preference tho. Great job!

Steve

 
George Ziniewicz

May 14, 2001, 07:49 PM

BTW, for the cloud effect I prefer blending modes:

GL_DST_COLOR, GL_ONE_MINUS_DST_ALPHA

The app lets you set any blend pair via a slider.

I am often surprised to see the results of blending interactively, I can never predict it, so must play with the slider.


zin

 
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