Particle Emitter for flowing water..?

[PranQster]

Progress...

I finally extracted the drop2.tga and andy.mtr files I needed, copied the relevant parts that I needed and made my own modified & renamed versions. Along with a modified .prt based on Doom3's snotdrip. I edited the drop2.tga to be brighter and have vertical stripes, rather than a spherical look and painted more black at the sides to make it more narrow.

I tried 'modulate' instead of 'add' and ended up with a lot of solid black around the outer edges of the particle where I want transparency. I then went back to 'add' and lowered the color values for the emitter to very low figures... Red 15 Green 0 and Blue 3.

Almost there, but the effect looks a bit thin and too translucent.

[shadow_ibix]

With blend modulate, the colour bright white on your texture turns see-through. Black is shadow. It is good at creating shadows.

 

With blend add, the colour black on your texture turns see-through and everything is glow-in-the-dark. It is good at magical effects.

 

But I think what you want is

blend blend

It causes your texture to be copied to the screen, and the alpha channel of your texture is used normally to fade into the existing background. This is more expensive, so do not make hundreds of very large particles as this may cause slowdown (on lower spec machines).

 

Since I am going over the options, the setting

blend gl_dst_color, gl_src_color

is also useful, like modulate but you can also create areas where 'there is more light', with a texture where white adds light, black adds shadow and gray is transparent. This sort of setting, or blend modulate (which is the same as blend filter) is good with a 'baked' lightmap that was output from a 3d editor program (where the 3d editor creates a black and white texture with the shadows on it for the object you made, since the 3d editor program can sometimes output much nicer shadows than doom3 would be able to render realtime).

 

Of course, you want to create a droplet of wine, not light or darkness, and thus the blend blend mode which copies your texture represents what happens; you see the droplet you draw on the texture.

[OrbWeaver]

But I think what you want is

blend blend

It causes your texture to be copied to the screen, and the alpha channel of your texture is used normally to fade into the existing background. This is more expensive, so do not make hundreds of very large particles as this may cause slowdown (on lower spec machines).

 

I don't see any reason why blend blend should be any more performance intensive than the others; it's just multiplying different components of the RGBA source and destination pixels. Certainly the expense of texture blending is trivial compared to the real lighting calculations that the engine is doing.

 

Since I am going over the options, the setting

blend gl_dst_color, gl_src_color

is also useful, like modulate but you can also create areas where 'there is more light', with a texture where white adds light, black adds shadow and gray is transparent.

 

That's an interesting one actually, basically taking the output of blend modulate and doubling it, so you can produce a result that is brighter than the original.

[shadow_ibix]

I don't see any reason why blend blend should be any more performance intensive than the others; it's just multiplying different components of the RGBA source and destination pixels. Certainly the expense of texture blending is trivial compared to the real lighting calculations that the engine is doing.

 

It was my experience some time ago with particles, especially if large (10% of screen) and a lot (hundreds). It depended on the hardware - with newer but also different manufacturers working better. Basically it needs more 'pixel math', and thus has a bigger influence on the FPS. So go ahead and use it, because it is what you want, but I wanted to caution against too-much, too-large.

 

Also, I think with AlphaTest 0.4 or 0.8 or so, you can change an alpha-ed texture from blurry edges to one with sharply defined edges, like for a fence, when you look up close.

 

That's an interesting one actually, basically taking the output of blend modulate and doubling it, so you can produce a result that is brighter than the original.

 

Yes, but the doubling causes colour-changes. Its not HDR

[OrbWeaver]

It was my experience some time ago with particles, especially if large (10% of screen) and a lot (hundreds). It depended on the hardware - with newer but also different manufacturers working better. Basically it needs more 'pixel math', and thus has a bigger influence on the FPS. So go ahead and use it, because it is what you want, but I wanted to caution against too-much, too-large.

 

That is good advice in any case, excessive particle effects can cause performance issues. I suppose there are a couple more pixel operations for alpha blending since you need to calculate 1-alpha as well as alpha and multiply source and destination colours by the two different values, which I guess might have been the cause of your experienced problems on older hardware.

 

I wouldn't advise mappers to choose blend modes for performance reasons though, rather to use the blend mode which is required and limit the number of particles to keep framerates from dropping. You can achieve decent-looking smoke effects with as few as 3 (large) particles, for example.