   How to do snow on large landscapes?
  How to do realistic snow on large landscapes? When I move camera and emitter(plane) to new location there is no snow plus it takes time for new snow to fall to the ground. What is the best solution to this problem? I tryed snow relative to emitter but it also doesnt feel right especialy when I move camera in circles.   
  as for the snow particles i would animate them in a circle around the player this gives good results even for rotating viewsas for coloring the landscape, you could use a large texture that spans the whole mapuse a 2d perlin noise map smooth it strech it by factor 8 apply an exponential filter and add this perlin noise map  with a blending factor of ~0.05f to the snow map you span over your terrainthis should give you decent results,you might want to splat you terrain and the snow map into several smaller maps to get a better resolution   ;  Your snow emitter is a square plane more or less? placed above the camera?Here is a fun trick, to simulate having an infinite size emitter.(its not really infinite, you just 'tile repeat' the snow like those topdown rpg games tile their landscapewhat if, to the front, back, left and right of your emmitter you make 4 exact copies of it each with exact copies of all the snowflakes?Then, when the camera moves in a given direction, you make the emitter tile on that side the new center, delete 3 of the old ones, and spawn 3 new onces centered where you are now?The key is that all of these emitters and snowflakes are really the Same emitter with the same snowflakes, just Rendered 5 times in different directionsIt as as though there is no edge to the cube of snowflakes, it just wraps around back on itself.In this way.... the snowflakes remain constant all the time, you don't need to 'wait' for new ones to fall when you moveCheck out the ascii art below **@* * ***@ *  * *@*  *;  Theres a nice article about snow in one of the gpgems books. Basically the idea is to have a snow particle texture with a number of snow particles on it, transparent otherwise. You draw this on a two cones joined base to base around the player. You scroll the texture coordinates to give the illusion of snow falling, and multitexture it with the texture at different scales to give the illusion of parallax. When the player moves, you have to tilt the double cone in the direction the player moves.   ;  Thanks for help. I'll do 5 emitters!   ;  And the cones! Tnx.   ;Quote:Original post by haphazardlynamedYour snow emitter is a square plane more or less? placed above the camera?Here is a fun trick, to simulate having an infinite size emitter.(its not really infinite, you just 'tile repeat' the snow like those topdown rpg games tile their landscapewhat if, to the front, back, left and right of your emmitter you make 4 exact copies of it each with exact copies of all the snowflakes?Then, when the camera moves in a given direction, you make the emitter tile on that side the new center, delete 3 of the old ones, and spawn 3 new onces centered where you are now?The key is that all of these emitters and snowflakes are really the Same emitter with the same snowflakes, just Rendered 5 times in different directionsIt as as though there is no edge to the cube of snowflakes, it just wraps around back on itself.In this way.... the snowflakes remain constant all the time, you don't need to 'wait' for new ones to fall when you moveCheck out the ascii art below **@* * ***@ *  * *@*  *can you explain this a little bit more?I implemented a snow/rain system a few years back where each particle was spawned in a randow position on a circle around the cameraI just spawned them at different heights and removed snow that is outside the radius of the circlethis worked quite well   ;  I was thinking of suggesting just what you mentioned, -spawn the snowflakes at random start heights, to avoid having to 'wait for them to fall'However i thought that perhaps having them pop into existance in thin air might look odd compared to actually falling from sky.Which is why I came up with this idea **@* *So, if we don't want flakes spawning midair, then they must spawn from sky, but if they spawn from sky, then we have the issue of waiting for them to fallOne way of solving the falling time issue, is to get a bigger radius emitter, so that even when the camera is moving, the flakes at the edge of the emitter are far enough away that theyve already fallen.My suggestion is essentially a bigger emitter, however I have a 'Cute' trick to recycle snow flakes so you don't actually have to spend more CPU on having a giant emitter.Instead I keep the same small size emitter, with the same number of snowflakes, but shift and Re-Render everything once in each direction North South East and West. Each snowflake appears 5 times, but in different places, you probably won't notice.Also, instead of having the emitters directly Linked to the camera, they 'walk' as the camera moves, so you don't have the problem of snowflakes following you around.(however, depending on how you track flake positions, this 'walking' feature of the emitter may be unneeded);  You guys handled the precipitation...  I'll discuss the detail.My snow handles things with an LOD sort of approach.  If a snowflake is close enough to the player, a billboard of a snowflake is drawn instead of a translucent point.  You have to be careful with this and make sure you don't emphasize the snowflake too much.  In other words, make sure it isn't blatantly obvious or big;  If it's suddle, the player will run around in your snow and casually notice that he/she can actually see each individual snowflake.You also want to add footprints to the snow, and rather then having them linearly fade out, have them fade out at a certain distance but get "pixeled out" if they are close to the player.  By this i mean they should have white dots gradually dotted onto them until they disappear, as if the snow was slowly filling them in.For the precipitation, make sure it isn't linear.  This means add changing wind, and more importantly gusts.  If you stand still and watch the snow, it should blow around realistically, even "flow."  This isn't really that hard to do if you can project a warp map.  This is actually something I haven't implemented yet, but it shouldn't be too hard and I look forward to getting around to it.Finally, if your game involves some type of bleeding, you want to make sure the blood seeps into the snow properly.  I found this to actually be a pretty easy result to achieve as long as you don't fade between blood splotches... make it animated.  The red contrasted on the blizzardy white, coupled with a good soundtrack, can make you gasp   ;  I did a variation on what Basiror sad. I removed snow that is outside my boundingbox and mirror them to the oposite side(changing position and life). It seem to work ok.   