Hi, Caleb.
I’ve been messing around with CBEffects trying to create a realistic snow effect to no effect. I found this nice Javascript example of what I’d like, but it uses cosine and sine functions for particle movement. I was wondering if you could help me build something like this using CBEffects.
http://thecodeplayer.com/walkthrough/html5-canvas-snow-effect
Thanks.
I’m not sure about the whole CBEffects thing because iv’e never used it but you can try this.
I think if you do a little bit of touch up and polish this will look perfect!
You can put this in a main.lua and play it. It’s a sample.
centerX = display.contentCenterX centerY = display.contentCenterY actualW = display.actualContentWidth actualH = display.actualContentHeight local physics = require( "physics" ) physics.start() local snow = {} local sCounter = 1 local sTimer local BG = display.newRect( centerX, centerY, actualW, actualH ) BG: setFillColor( 0.5, 0.6, 1 ) local function createSnow() local randomSize = math.random( 1, 3 ) local randomX = math.random( centerX - actualH/2, centerX + actualH/2 ) local randomLeftRight = math.random( -50, 50 ) local randomDown = math.random( 101, 150 ) snow[sCounter] = display.newCircle( randomX, centerY - actualH/2 - 20, randomSize ) snow[sCounter].value = sCounter physics.addBody( snow[sCounter], "dynamic" ) snow[sCounter].gravityScale = 0 snow[sCounter]:setLinearVelocity( randomLeftRight, randomDown ) snow[sCounter].alpha = 0.8 sCounter = sCounter + 1 end sTimer = timer.performWithDelay( 150, createSnow, -1 )
Good luck!
–SonicX278
Thats pretty good snow SonicX278 - how do you go about coding that, trial and error or ‘off the top’ of a very clever head 
?
Here’s the beauty of a particle effects system:
local vent = CBE.newVent({preset = "snow"})
That was off the top of my head in 2 min. Nothing fancy. Could be better.
–SonicX278
Oh and if you don’t want physics you can easily get transition.to working.
–SonicX278
One important thing to note about @SonicX278’s approach: Your particles are never destroyed. If you run it for any reasonable amount of time, things will quickly get messy. You should add a routine in there somewhere to destroy particles or hide them to reuse them or something.
I’m on my mobile phone right now but that is very easy to do. It’s one simple function. I will be able to fix that problem later on today.
–SonicX278
Aye. Here’s an improved version of @SonicX278’s code, without the unnecessary globals, with snowflakes that don’t bump into objects in the scene, and with a method that removes snowflakes as they go outside the screen. Also, I’ve removed the unneeded table in favor of local snowflakes and a group, which is cleaner and won’t fail when the number of snowflakes goes over 15 digits (admittedly rarely, but still… :D).
The loop through each snowflake is required because @SonicX278 used physics. Without physics, we could use a transition and remove the snowflake when it’s done, but with it, we need to know when a snowflake goes outside the screen.
local centerX = display.contentCenterX local centerY = display.contentCenterY local actualW = display.actualContentWidth local actualH = display.actualContentHeight local physics = require( "physics" ) physics.start() local sTimer local BG = display.newRect( centerX, centerY, actualW, actualH ) BG:setFillColor( 0.5, 0.6, 1 ) local snow = display.newGroup() local function checkFlakes() for i = snow.numChildren, 1, -1 do if snow[i].y - snow[i].contentHeight \> actualH then display.remove(snow[i]) end end end local function createSnowflake() local randomSize = math.random( 1, 3 ) local randomX = math.random( centerX - actualH \* 0.5, centerX + actualH \* 0.5 ) local randomLeftRight = math.random( -50, 50 ) local randomDown = math.random( 101, 150 ) local flake = display.newCircle( randomX, centerY - actualH \* 0.5 - 20, randomSize ) physics.addBody(flake, "kinematic") flake.isSensor = true -- So it doesn't collide with objects in the scene flake:setLinearVelocity( randomLeftRight, randomDown ) flake.alpha = 0.8 snow:insert(flake) end sTimer = timer.performWithDelay( 150, createSnowflake, -1 ) Runtime:addEventListener("enterFrame", checkFlakes)
[EDIT]: Sorry, @Rob2, I just realized @SonicX278 and I hijacked the thread to talk about non-CBE particles… To answer the original question, the one-liner should do the trick.
Oh sorry! I just saw that I’m not in the general questions forum!
–SonicX278
I’m not sure about the whole CBEffects thing because iv’e never used it but you can try this.
I think if you do a little bit of touch up and polish this will look perfect!
You can put this in a main.lua and play it. It’s a sample.
centerX = display.contentCenterX centerY = display.contentCenterY actualW = display.actualContentWidth actualH = display.actualContentHeight local physics = require( "physics" ) physics.start() local snow = {} local sCounter = 1 local sTimer local BG = display.newRect( centerX, centerY, actualW, actualH ) BG: setFillColor( 0.5, 0.6, 1 ) local function createSnow() local randomSize = math.random( 1, 3 ) local randomX = math.random( centerX - actualH/2, centerX + actualH/2 ) local randomLeftRight = math.random( -50, 50 ) local randomDown = math.random( 101, 150 ) snow[sCounter] = display.newCircle( randomX, centerY - actualH/2 - 20, randomSize ) snow[sCounter].value = sCounter physics.addBody( snow[sCounter], "dynamic" ) snow[sCounter].gravityScale = 0 snow[sCounter]:setLinearVelocity( randomLeftRight, randomDown ) snow[sCounter].alpha = 0.8 sCounter = sCounter + 1 end sTimer = timer.performWithDelay( 150, createSnow, -1 )
Good luck!
–SonicX278
Thats pretty good snow SonicX278 - how do you go about coding that, trial and error or ‘off the top’ of a very clever head ?
Here’s the beauty of a particle effects system:
local vent = CBE.newVent({preset = "snow"})
That was off the top of my head in 2 min. Nothing fancy. Could be better.
–SonicX278
Oh and if you don’t want physics you can easily get transition.to working.
–SonicX278
One important thing to note about @SonicX278’s approach: Your particles are never destroyed. If you run it for any reasonable amount of time, things will quickly get messy. You should add a routine in there somewhere to destroy particles or hide them to reuse them or something.
I’m on my mobile phone right now but that is very easy to do. It’s one simple function. I will be able to fix that problem later on today.
–SonicX278
Aye. Here’s an improved version of @SonicX278’s code, without the unnecessary globals, with snowflakes that don’t bump into objects in the scene, and with a method that removes snowflakes as they go outside the screen. Also, I’ve removed the unneeded table in favor of local snowflakes and a group, which is cleaner and won’t fail when the number of snowflakes goes over 15 digits (admittedly rarely, but still… :D).
The loop through each snowflake is required because @SonicX278 used physics. Without physics, we could use a transition and remove the snowflake when it’s done, but with it, we need to know when a snowflake goes outside the screen.
local centerX = display.contentCenterX local centerY = display.contentCenterY local actualW = display.actualContentWidth local actualH = display.actualContentHeight local physics = require( "physics" ) physics.start() local sTimer local BG = display.newRect( centerX, centerY, actualW, actualH ) BG:setFillColor( 0.5, 0.6, 1 ) local snow = display.newGroup() local function checkFlakes() for i = snow.numChildren, 1, -1 do if snow[i].y - snow[i].contentHeight \> actualH then display.remove(snow[i]) end end end local function createSnowflake() local randomSize = math.random( 1, 3 ) local randomX = math.random( centerX - actualH \* 0.5, centerX + actualH \* 0.5 ) local randomLeftRight = math.random( -50, 50 ) local randomDown = math.random( 101, 150 ) local flake = display.newCircle( randomX, centerY - actualH \* 0.5 - 20, randomSize ) physics.addBody(flake, "kinematic") flake.isSensor = true -- So it doesn't collide with objects in the scene flake:setLinearVelocity( randomLeftRight, randomDown ) flake.alpha = 0.8 snow:insert(flake) end sTimer = timer.performWithDelay( 150, createSnowflake, -1 ) Runtime:addEventListener("enterFrame", checkFlakes)
[EDIT]: Sorry, @Rob2, I just realized @SonicX278 and I hijacked the thread to talk about non-CBE particles… To answer the original question, the one-liner should do the trick.
Oh sorry! I just saw that I’m not in the general questions forum!
–SonicX278