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How to create Black Smoke in TGE ?

by Ali Khan · in Torque Game Engine · 10/11/2006 (9:20 pm) · 9 replies

Hi everyone,

I am trying to create black colored particles for my smoke but I am unable to do it. I have tried setting the particle color to all black but that results in particles disappearing completely.

I also tried putting a black particle texture but that doesn't work either and the particle remain white. The black part of the texture disappears as alpha. It seems the texture is not being composited onto the particle but instead it is just being used as an alpha on which the particle color is composited.

So if my assumptions are true then I guess there is no way to create black smoke particles in TGE.

This would be bad, right ?

Ali Khan.
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Torque Owner Alan James
Really Really Good Things Studio
#1
10/11/2006 (9:49 pm)
@Ali, see if this works for you.

Create (or add to a executed script file, like "chimneyfire.cs" or the like):

datablock ParticleData(DarkSmoke)
{
   textureName          = "~/data/shapes/particles/smoke";
   dragCoefficient     = 0.0;
   gravityCoefficient   = -0.5;   // rises slowly
   inheritedVelFactor   = 0.00;
   lifetimeMS           = 1900;
   lifetimeVarianceMS   = 450;
   useInvAlpha = false;
   spinRandomMin = -30.0;
   spinRandomMax = 30.0;

   colors[0]     = "0.6 0.6 0.0 0.1";
   colors[1]     = "0.6 0.6 0.0 0.1";
   colors[2]     = "0.0 0.0 0.0 0.0";

   sizes[0]      = 4.5;
   sizes[1]      = 4.5;
   sizes[2]      = 4.5;

   times[0]      = 0.0;
   times[1]      = 0.5;
   times[2]      = 1.0;
};

datablock ParticleEmitterData(DarkSmokeEmitter)
{
   ejectionPeriodMS = 200;
   periodVarianceMS = 10;

   ejectionVelocity = 0.15;
   velocityVariance = 0.05;

   thetaMin         = 3.0;
   thetaMax         = 90.0;  

   particles = "DarkSmoke";
};

Here's the png:
www.reallyreallygoodthings.com/screens3/smoke.png

Here's an image:
www.reallyreallygoodthings.com/screens3/screenshotSmoke.jpg
Hope this is kind of what you're looking for.

- Alan

Torque Owner Ali Khan
#2
10/11/2006 (11:19 pm)
I tried copying all these values, also used the texture you gave. The lower end particle are yellow but the higher particles are invisible, instead of black.

Torque Owner Alan James
Really Really Good Things Studio
#3
10/11/2006 (11:31 pm)
Oops.

Drop this after the code above:
datablock ParticleEmitterNodeData(DarkSmokeEmitterNode)
{
   timeMultiple = 1;
};

I *think* that should do it...I hope...

Torque Owner Ali Khan
#4
10/11/2006 (11:58 pm)
I have already done that ..

Torque Owner Alan James
Really Really Good Things Studio
#5
10/12/2006 (12:07 am)
Crap. Sorry. Grabbed the wrong emitter. Gave you the fire not the smoke one! 

datablock ParticleData(ChimneySmoke2)
{
   textureName          = "~/data/shapes/particles/smoke";
   dragCoefficient     = 0.0;
   gravityCoefficient   = -0.2;   // rises slowly
   inheritedVelFactor   = 0.00;
   lifetimeMS           = 6000;
   lifetimeVarianceMS   = 250;
   useInvAlpha = true;
   spinRandomMin = -30.0;
   spinRandomMax = 30.0;

   sgAllowLighting = true;

   colors[0]     = "0.10 0.10 0.10 0.1";
   colors[1]     = "0.20 0.20 0.10 0.1";
   colors[2]     = "0.10 0.10 0.10 0.0";

   sizes[0]      = 1.5;
   sizes[1]      = 4.75;
   sizes[2]      = 8.5;

   times[0]      = 0.0;
   times[1]      = 0.5;
   times[2]      = 1.0;
};

datablock ParticleEmitterData(ChimneySmoke2Emitter)
{
   ejectionPeriodMS = 20;
   periodVarianceMS = 5;

   ejectionVelocity = 0.25;
   velocityVariance = 0.10;

   thetaMin         = 0.0;
   thetaMax         = 90.0;  

   particles = ChimneySmoke2;
};

datablock ParticleEmitterNodeData(ChimneySmoke2EmitterNode)
{
   timeMultiple = 1;
};

Sorry. =P

Torque Owner Paul /*Wedge*/ DElia
#6
10/12/2006 (11:27 am)
The key line is this:
useInvAlpha = true;
That changes the blend mode of particles to be subtractive instead of additive, allowing for darker colours.

Torque Owner Ali Khan
#7
10/12/2006 (9:15 pm)
This worked great. Thanks a lot.

I must say though, useInvAlpha might not be the right name for this attribute. It should be blend mode or something. I mean inverse alpha implies that texture alpha will be inverses to make opaque areas transparent and vice versa.

Anyways all is good as long as the funcionality is there.

Torque Owner Ronald J Nelson
Code Hammer Games
#8
10/14/2006 (12:48 am)
Nice and very useful. Now if someone has only made a really nice spark emmiter like a metal contact spark.

Milt-Tec Corp (#0001)
Default Studio Name
#9
10/20/2006 (2:54 pm)
You might want to try using the ParticleEditor. It is incredibly easy to use and you get instant results.