Shader alpha problem

[rgoer]

Ok, ok, this is a real pain in the ass. I've got a four-step shader and it just isn't working out the way I predicted. Here are two shots of it in-game, illustrating the problem:

shot 1 and shot 2

See how, in the second shot, the "words" start getting alpha-added again over the "back" of the bottom? Here's my shader code:

textures/roger/round_ad
{
	surfaceparm	nomarks
	surfaceparm	nonsolid
	q3map_nolightmap
	q3map_onlyvertexlighting
	cull	disable
    {
        map textures/roger/round_ad
        blendFunc GL_ONE GL_ONE
        tcMod scroll 0.3 0
    }
    {
	map textures/roger/text_1
	blendFunc GL_ONE GL_ONE
	tcMod scroll 0 -0.1
    }
    {
	map textures/roger/text_1_alpha
	blendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA
	detail
    }
}

and here is a shot that shows what the various images for the different steps are.

Can anybody tell me what I need to do to fix this shader?

[Lil Killa]

I might be wrong but I don't think there is a way to fix this. The grates have that same problem that your shader is having if they are on top of each other. I would suggest putting in a cylinder that is covered in black on the inside but then again you loose that "transparent" effect . I have had the same problem with some of my shaders before too and it sucks...... maybe Leslie knows some shader stuff all we need now is for him to see your helpless pless for help

[Leslie Judge]

map maker 101 is right in a way. But if you take a look at LDJ's original of DOTF there the beams in the reactor have four transparent layers and they are correct.

As I'm at work now I can't try things out, but there is a thing I can suggest.

Why do you have the text itself and the alpha in separate textures? I think you could give the text_1_alpha's alpha channel to text_1 itself and leave out the 3rd stage like:

textures/roger/round_ad
{
        surfaceparm nomarks
        surfaceparm nonsolid
        surfaceparm trans
        q3map_nolightmap
        q3map_onlyvertexlighting
        cull	disable
    {
        map textures/roger/round_ad
        blendFunc GL_ONE GL_ONE
        tcMod scroll 0.3 0
    }
    {
        map textures/roger/text_1
        blendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA
        tcMod scroll 0 -0.1
    }
}

I added surfaceparm trans too to be sure that it is transparent. At home I'll try to do these because I'm not quite sure I'm right about the 2-stages-only solution if I'll not forget.

[rgoer]

The reason for the alpha being separate is this: the "words" texture is 2048 pixels tall and it tcMod scrolls vertically. However, I want the "words" to fade away as they fall down, so I needed an alpha map that was separate from the image. The alpha map is only 512 pixels tall. Am I making sense?

[wedge2211]

Do you have two cylinders there? You only need one (doesn't matter which way the matrix faces) if you use the keyword cull disable. But you probably already knew that.

LJ knows a bit more about shaders and alphas than I do...:P

[rgoer]

nope, just the one cylinder. I think I'm going to have to just give up on this effect... here is a .pk3 of a little test map that shows off, sort-of, the effect I was trying to get. You also can see the error. Maybe if you devmap the map you'll have a better idea of what I'm trying to do, and maybe somebody will know if it's fixable?

[Leslie Judge]

Originally posted by rgoer
The reason for the alpha being separate is this: the "words" texture is 2048 pixels tall and it tcMod scrolls vertically. However, I want the "words" to fade away as they fall down, so I needed an alpha map that was separate from the image. The alpha map is only 512 pixels tall. Am I making sense?

Hehh, sorry, I wasn't able to get online since my last post. And of course I didn't recognize that the words scroll vertically. Again: if I'll have time at home today I'll play with it a little to see if I can find out something.

[lauser]

Bah!! I'm just trying to get the silly shader to work period!! All I get is a solid brush when I play the map. I made the shader file and stuck it in the shader folder. The shader I made is the forcefield from doomgiver. All I did was change the color of it.

Any help would be greatly appreciated.

Should I try doing a devmap or?

[rgoer]

Ging, until you pak your stuff up into a .pk3, you have to make sure you "set sv_pure 0" before you "devmap <yourmap>"

[lauser]

Yes I know that I was just checking thanks buddy!!