Light shadows?

[RPG]

UPD. This feature already in game engine.

Is it necessary?
A little engine modification.



Source code (see post №10):
http://forum.cubers.net/thread-2116-post...l#pid33761

[FleshyPod]

Lighting in AC is poor as opposite Sauer engine. But if engine let players hide in dark corner it will add something to gameplay.

[eftertanke]

O.o I didn't know that was possible with the Cube engine. Did you backport something?

[RPG]

I just added occlusion test in lighting function:)

[Andrez]

Wow. Looks so progressive!

[eftertanke]

Very nice.

[RPG]

Some light effects may be more realistic:

[eftertanke]

I'd love seeing this creep into an official release. Haha.

[MykeGregory]

I'd love seeing this creep into an official release.

F1!
that would be good.

[RPG]

Code changed:
In file worldlight.cpp:
replace function:

[SELECT ALL] Code:

void lightray(float bx, float by, const persistent_entity &light, float fade = 1, bool flicker = false)     // done in realtime, needs to be fast
{
    disableraytable();
    float lx = light.x+(flicker ? (rnd(21)-10)*0.1f : 0);
    float ly = light.y+(flicker ? (rnd(21)-10)*0.1f : 0);
    float dx = bx-lx;
    float dy = by-ly;
    float dist = (float)sqrt(dx*dx+dy*dy);
    if(dist<1.0f) return;
    int reach = light.attr1;
    int steps = (int)(reach*reach*1.6f/dist); // can change this for speedup/quality?
    const int PRECBITS = 12;
    const float PRECF = 4096.0f;
    int x = (int)(lx*PRECF);
    int y = (int)(ly*PRECF);
    int fadescale = (int)(fade*PRECF);
    int l = light.attr2*fadescale;
    int stepx = (int)(dx/(float)steps*PRECF);
    int stepy = (int)(dy/(float)steps*PRECF);
    int stepl = (int)(l/(float)steps); // incorrect: light will fade quicker if near edge of the world

    if(maxtmus)
    {
        l /= lightscale;
        stepl /= lightscale;

        if(light.attr3 || light.attr4)      // coloured light version, special case because most lights are white
        {
            if(flicker)
            {
                int dimness = rnd((((255<<PRECBITS)-(int(light.attr2)+int(light.attr3)+int(light.attr4))*fadescale/3)>>(PRECBITS+4))+1);
                x += stepx*dimness;
                y += stepy*dimness;
            }

            if(OUTBORD(x>>PRECBITS, y>>PRECBITS)) return;

            int g = light.attr3*fadescale;
            int stepg = (int)(g/(float)steps);
            int b = light.attr4*fadescale;
            int stepb = (int)(b/(float)steps);
            g /= lightscale;
            stepg /= lightscale;
            b /= lightscale;
            stepb /= lightscale;
            loopi(steps)
            {
                sqr *s = S(x>>PRECBITS, y>>PRECBITS);
                s->r = min((l>>PRECBITS)+s->r, 255);
                s->g = min((g>>PRECBITS)+s->g, 255);
                s->b = min((b>>PRECBITS)+s->b, 255);
                if(SOLID(s)) return;
                if(isoccluded(light.x, light.y, x>>PRECBITS, y>>PRECBITS, 1)) return;
                x += stepx;
                y += stepy;
                l -= stepl;
                g -= stepg;
                b -= stepb;
                stepl -= 25;
                stepg -= 25;
                stepb -= 25;
            }
        }
        else        // white light, special optimized version
        {
            if(flicker)
            {
                int dimness = rnd((((255<<PRECBITS)-(light.attr2*fadescale))>>(PRECBITS+4))+1);
                x += stepx*dimness;
                y += stepy*dimness;
            }

            if(OUTBORD(x>>PRECBITS, y>>PRECBITS)) return;

            if(hdr.ambient > 0xFF) loopi(steps)
            {
                sqr *s = S(x>>PRECBITS, y>>PRECBITS);
                s->r = min((l>>PRECBITS)+s->r, 255);
                s->g = min((l>>PRECBITS)+s->g, 255);
                s->b = min((l>>PRECBITS)+s->b, 255);
                if(SOLID(s)) return;
                if(isoccluded(light.x, light.y, x>>PRECBITS, y>>PRECBITS, 1)) return;
                x += stepx;
                y += stepy;
                l -= stepl;
                stepl -= 25;
            }
            else loopi(steps)
            {
                sqr *s = S(x>>PRECBITS, y>>PRECBITS);
                s->r = s->g = s->b = min((l>>PRECBITS)+s->r, 255);
                if(SOLID(s)) return;
                if(isoccluded(light.x, light.y, x>>PRECBITS, y>>PRECBITS, 1)) return;
                x += stepx;
                y += stepy;
                l -= stepl;
                stepl -= 25;
            }
        }
    }
    else        // the old (white) light code, here for the few people with old video cards that don't support overbright
    {
        loopi(steps)
        {
            sqr *s = S(x>>PRECBITS, y>>PRECBITS);
            int light = l>>PRECBITS;
            if(light>s->r) s->r = s->g = s->b = (uchar)light;
            if(SOLID(s)) return;
            //if(isoccluded(light.x, light.y, x>>PRECBITS, y>>PRECBITS, 1)) return;
            x += stepx;
            y += stepy;
            l -= stepl;
        }
    }
}

Pay attention at "isoccluded" function. disableraytable was added to fix "FOV shadow" bug.

I think this feature will put mapping in a new "light":).

[eftertanke]

I think this feature will put mapping in a new "light":).

Budum bum, ching!

[Mr.Floppy]

Wow, that looks pretty awesome!

Why hasn't this been done before? Is it heavy on resources? If this is compatible with the low-end machines, it definitely would be a great addition.

Damn, I do hope it is! :P

[Gibstick]

Oh beautiful!

Who cares if it's heavy on resources, as long as it is optional. Besides, we have dynamic stencil shadows (killed my other computer when they were enabled) so why not :D

[RPG]

The main problem is an idea. Technical solution is the second problem. As you see I changed only 4 lines of source, my first change was 1 line of code.

About speed. Lighting calculation done by CPU only. I have 3 GHz CPU and can't test that, but I think my improvement will not slow down the game. Function "isoccluded" very fast because it calls every frame many times. Light calculation happens only once - when map loads (or you edit light params).

Also you must know, that it is only "emulation" of shadows due to limitations of game engine. My code will not generate object shadows, it's possible only in Cube 2 engine. These shadows are "2D", so it is shadows only for walls, ignoring boxes or windows.

---

As you can see only walls cast shadows, boxes can't.

[V-Man]

I see: Solids = shadow, everything else can't do it -- due to the 2D nature of AC map layout.

[RPG]

Right. Better shadows - it's easier to take cube 2 and make AC mod:)

[V-Man]

Lawl.
Still, any sharp shadows as in your pics above are looking great!

[Mael]

Well thanks for doing this for me. I've been bitching about the shadows for a while.

[Joe Smith]

Awesome, i was wondering if the shadow is always that dark or does it matter the brightness of the light, or would there be a way to get the shadow a lighter shade.
[/align]

[V-Man]

More lights will probably give a diffuse look.

[RPG]

Fixed error in old white code (error while compilation). See post#10.

Official maps has huge amount of lights, so shadows effect is not as noticeable. To make maps more realistic, we must remake lights on all maps. When you create new map it is more noticeable.

[Fate]

WOAH! This looks very nice!

This can give mapping a new edge :P

[Ronald_Reagan]

What lines did you replace/modify exactly? You said it was only 4 lines or so. Did you just add them? Or did you have to modify some? Looks nice btw.

[RPG]

http://ompldr.org/vNzRrZQ

[Ronald_Reagan]

Nice!
That is some pretty neat code you have going on there :)

[FleshyPod]

So normal/bump mapping will be impossible to do with this lighting?

[RPG]

No, bumpmapping/parallaxmapping is another technology. They are CPU hungry.

If you want parallax/bump - play cube 2.

[FleshyPod]

No, bumpmapping/parallaxmapping is another technology. They are CPU hungry.

If you want parallax/bump - play cube 2.

So I do :) but I wonder how ac will look like with this.

[RPG]

The main principle of AC - to be simple and fast. I think there will never be slow visual effects.

[RIPBillyMays]

I think it looks great, but if implemented the lighting would have to be redone in a lot of maps.