Oolite Bulletins

Arexack_Heretic wrote:

Not very usefull for displaying the detail on that specific add though.

Arexack_Heretic wrote:

What I had in mind was a simple flip-state shader, that flips through its textures rather in a stepped/discreet sine than the normal sine used in the Freaking Thargoids example.

Arexack_Heretic wrote:

As static picture, it should work for the YAH!_oxp on a default grey background.
...will probably look better with a fadeOut1-grey-fadeIn2 though
...have to think on possible mathematical tricks to get the pictures to display longer than the blank-screen.

uniform float       time;

const float         kDisplayTime = 5.0;
const float         kFadeTime = 1.5;
const float         kLoopTime = 4.0 * kDisplayTime; // 4.0 as in the number of frames

/* ... */

float AdvertContribution(in float offset)
{
    float t = mod(time - offset + kFadeTime, kLoopTime);
    
    float rising = kFadeRatio * t;
    float falling = (kFadeRatio * (kDisplayTime + kFadeTime - t));
    return clamp(min(rising, falling), 0.0, 1.0);
}

/* ... */

// Calculates the intensity of a single virtual pixel
vec3 PixelColor(in vec2 virtualPixelCoord)
{
    virtualPixelCoord /= 4;
    
    // Load texture values for each frame
    vec3 frame0Col = texture2D(tex0, virtualPixelCoord).rgb;
    vec3 frame1Col = texture2D(tex0, virtualPixelCoord + vec2(0.0, 0.25)).rgb;
    vec3 frame2Col = texture2D(tex0, virtualPixelCoord + vec2(0.0, 0.50)).rgb;
    vec3 frame3Col = texture2D(tex0, virtualPixelCoord + vec2(0.0, 0.75)).rgb;
    
    /*  Calculate contribution of each texture.
        Animation works as follows: each billboard is shown for kDisplayTime + kFadeTime seconds
        each display cycle. The beginning and end of this time is a crossfade. kDisplayTime can
        be thought of as the time each texture is at >= 50% visibility.
        The animation cycle starts with tex0Contrib just having reached 1.0.
    */
    float frame0Contrib = AdvertContribution(0.0);
    float frame1Contrib = AdvertContribution(kDisplayTime);
    float frame2Contrib = AdvertContribution(2.0 * kDisplayTime);
    float frame3Contrib = AdvertContribution(3.0 * kDisplayTime);
    
    vec3 result;
    result  = frame0Col * frame0Contrib;
    result += frame1Col * frame1Contrib;
    result += frame2Col * frame2Contrib;
    result += frame3Col * frame3Contrib;
    
    return result;
}

Arexack_Heretic wrote:

With possible transparency, the dream of putting animated neon signs outside my Hermitage-wateringhole comes one step closer.[/code]
Let me reiterate: transparency may seem to work under some circumstances, but it doesn’t really. You will eventually run into weird artefacts that you can’t fix.

Arexack_Heretic wrote:

No idea whether you seriously intend to work this out to perfection or whether you are just playing around with the possibilities...

I intend to finish it off, some time. Being distracted by this delayed 1.68 for several days. Now being distracted by extending JavaScript support is distracting me from this. :-)

Arexack_Heretic wrote:

...Is there a possibility to bodge in a few (determined by system richness?) random 'broken' pixels or a triggered 'static' wave?

I added the entity_personality uniform (a per-entity random number) for this precise reason, but implementing a sufficiently random-looking noise function based only on entity_personality and texture co-ordinates turned out to be challenging. Using those factors + a noise texture might do it. (There’s also a family of noise() functions in GLSL, but they’re not implemented on all hardware.) At the very least, entity_personality can be used to allow multiple signs that aren’t in perfect sync.

Arexack_Heretic wrote:

...Can this display a scrolling text?

Arexack_Heretic wrote:

looks like oolite draws objects the same way elite did, leaving out the occluded vertices and edges/faces.