Laser projected hologram effect?

AlecMoody

I am trying to create a better effect for a laser projected hologram using unity + shaderforge. I would really like the appearance of the light rays sweeping back and forth and flickering so it looks like the rays are drawing the hud image. Has anyone done this effect before in a shader? Scrolling textures side to side doesn't give the look I want since the rays need to appear to pivot around a fixed point at the base. The only way I can think of to do it to render out an animation in 3dsmax and use a flip book or movie texture.

The effect I have now is passable but not as cool as what I have in my head:

[ame="http://www.youtube.com/watch?v=N-m3pFjxs_w"]baseball hud hologram - YouTube[/ame]

CrazyButcher

hm, it looks like blurred random 1d stripes moving upwards (maybe more than one layer as well), and a second texture with the gradient fading out to top overlayed, then a little shader trickery to combine the layers, max and modulo...

if you animate which mip-map level you use, you get that sort of animated "wide blur" too.

AlecMoody

Chris,
The video is my current effect that I'm not happy with.

throttlekitty

I'm not a shader person, but maybe some tweaks to the "scanline-and-glitch" shader could help?

Doing it purely in geometry might be a solution. You could do geo for the frames and X shape (instead of big flat planes which i assume you have now), everything could be laid out in a long line in the UV, then warped a bit to handle the radial scan effect. Then a second alpha could be animated back and forth.

edit: need more coffee. that wouldn't quite work, a warped plane would be better.

Eric Chadwick

I would try scrolling rays across a cone or an arc. Visual examples are always best. Do you have any reference of fx you like?

i.e.

[ame="http://www.youtube.com/watch?v=oT5cKlOKgwo"]After Effects: Retro 3D Hologram - YouTube[/ame]

[ame="http://www.youtube.com/watch?v=M2Ize9piRWw"]Star Wars Kid- You Should Be Dancing - YouTube[/ame]

AlecMoody

Eric:
That watch is about perfect. It looks like that was done with some volumetric effects. I might be able to do something similar with a handful of animated cones and a few scrolling textures.

Edit:
Oh, there is an after effects tutorial in the video description.

RN

Simon has an article on a simulated volumetric glow, not sure if this is useful to you:
http://simonschreibt.de/gat/doom-3-volumetric-glow/

Eric Chadwick

You could certainly do this in 3d with scrolling texture, instead of a memory-hungry animated texture out of AfterEffects or similar.

I would layer the same texture over itself, panning in opposite directions, across a cone model.

If you have access to custom shaders, you could add a mask texture for the edges of the cone, aligned dynamically to the camera.

For example:
http://udn.epicgames.com/Three/VolumetricLightbeamTutorial.html

passerby

Ya more or less what people explained, if your still having problems on Monday I can make a sample up in ue4 to show how its done

CrazyButcher

paste this in shadertoy, might be useful for some of the scanline effects
https://www.shadertoy.com/new

float smootherstep(float edge0, float edge1, float x)
{
    // Scale, and clamp x to 0..1 range
    x = clamp((x - edge0)/(edge1 - edge0), 0.0, 1.0);
    // Evaluate polynomial
    return x*x*x*(x*(x*6.0 - 15.0) + 10.0);
}

void main(void)
{
	vec2 uv = gl_FragCoord.xy / iResolution.xy;
    
    float fadeLines = 10.0;
    
    float linesPerSecond = 4.0;
    vec2 dim = vec2(64,16);
    
    #if 1
    // discrete version
    vec2 sc = floor(uv * dim);
    // real
    #else
    vec2 sc = uv * dim;
    #endif
    
    float line = (sc.x + sc.y*dim.x);
    line = mod(line + iGlobalTime * linesPerSecond * dim.x,dim.x*dim.y);
    
    
    float frac      = (line/(dim.x*fadeLines));
    
    #if 0
    float intensity = frac;
    #else
    // play with 0,1 value...
    float intensity = smootherstep(0.0, 1.0, frac);
    #endif
    
	gl_FragColor = vec4(vec3(intensity),1.0);
}