Here is the grey scale alpha channel.
This is a discussion on New cloud effect for engine within the Game Programming forums, part of the General Programming Boards category; Here is the grey scale alpha channel....
As you can see the angle at which I took the screenshot and the sun angle don't quite match. A lesson to be learned here is that if you produce an image that looks good it just might fool the human eye into believing it's real or somewhat real.
Case in point:
1. There is a line on the right side of the first image. This is a direct result of tiling an image using the mirror function. Obviously my card does not mirror correctly or it is 1 pixel off for some reason which creates nasty blue grid lines.
2. The sky is really just the color I chose to clear the entire buffer with. It just so happens that I matched the color with the color in the pic and since the alpha channel is black in places and grey in others it looks as though the sky is showing through the clouds.
3. The sun is at the wrong angle for the lighting that is on the clouds. Also notice the perspective in the original image. The perspective comes from the picture being taken from the ground lookin up at about 45 degrees or 30 degrees above the horizon. What I really need is a cloud picture taken while looking straight up - thereby allowing me to create the perspective with my 3D engine instead of having the perspective molded into the bitmap.
4. The clouds look like they are at different Y levels above the ground. They are not. Notice the top right cloud and how it is stretched and looks weird? That's because this is a bitmap that is tiled onto a 3D plane - or a 3D square in the sky that represents the sky quad. It is one huge quad. I'm using some tricks with U,V coords to create the tiling and wrapping and such.
5. On the far left side of the image if you look you will see another faint line. Now look on either side of the image and you get a kind of kaleidescope image - the left matches the right exactly. This is because you are looking at about 3 grids of the same cloud image...but they are mirrored.
6. 250 FPS...wow man that's a lot. Yeah and it's also very misleading. There is no terrain in the shot and, in fact, there isn't any terrain being drawn at all. I'm re-working the terrain algo so it is not rendered in this pic, hence the enormous frame rates. No I'm not John Carmack - I won't get any where near 250 FPS when the terrain is drawn....unless my culling algos are perfect.
But none of you seemed to notice. Also be wary of screenshots because I only show you what looks good. Just like the game manufacturers show you screenshots of their game...they only show you the good stuff. They don't show you the ugly clipping/culling errors prevalent in just about every engine out there.
And while we are on the subject of illusions in games, I've also learned from my experience with Joint Ops: Typhoon Rising that AI and graphic engines are not as complete/smart as you think. A lot of it comes from the map maker making the AI 'look smart' by using lots of scripts to encode their actions. Also just from making my own maps and having objects glitch here and there....a lot of care is taken when designing maps and levels not to burden the engine beyond what it can handle...but still present a very good looking level. For instance in JO if you include too many trees...the thing crawls. But you can get the same effect as a dense jungle by using strategic placement of large trees, bushes, etc. I've had objects disappear completely, glitch, and have found objects that you should never use inside of buildings. The engine is not perfect but all the original coop maps and levels are built with all of this in mind so they don't experience the glitching. Overall I'd say that JO is not even 80% finished. There is a lot that has not been done yet.
All of this is simpy an optical illusion.....and it works.
Last edited by VirtualAce; 02-07-2005 at 08:54 PM.
I thought it was, but I googled for "glblendmode" just to check and got a load of results. So, blame google.Originally Posted by Darkness