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Light shadows?
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UPD. This feature already in game engine.
Is it necessary? A little engine modification. ![[Image: vNzQ4Nw.jpg]](http://ompldr.org/vNzQ4Nw.jpg) ![[Image: vNzQ4OQ.jpg]](http://ompldr.org/vNzQ4OQ.jpg) Source code (see post №10): http://forum.cubers.net/thread-2116-post...l#pid33761
23 Jan 11, 05:31PM
Lighting in AC is poor as opposite Sauer engine. But if engine let players hide in dark corner it will add something to gameplay.
23 Jan 11, 07:18PM
O.o I didn't know that was possible with the Cube engine. Did you backport something?
23 Jan 11, 07:43PM
I'd love seeing this creep into an official release. Haha.
23 Jan 11, 07:44PM
Code changed:
In file worldlight.cpp: replace function: 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":).
23 Jan 11, 08:46PM
23 Jan 11, 09:35PM
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
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
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. 
23 Jan 11, 10:31PM
I see: Solids = shadow, everything else can't do it -- due to the 2D nature of AC map layout.
23 Jan 11, 10:36PM
Right. Better shadows - it's easier to take cube 2 and make AC mod:)
23 Jan 11, 11:31PM
Lawl.
Still, any sharp shadows as in your pics above are looking great! 
23 Jan 11, 11:49PM
Well thanks for doing this for me. I've been bitching about the shadows for a while.
24 Jan 11, 05:07AM
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]
24 Jan 11, 06:01AM
More lights will probably give a diffuse look.
24 Jan 11, 06:51AM
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. 
24 Jan 11, 08:04AM
(This post was last modified: 24 Jan 11, 08:04AM by 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.
24 Jan 11, 08:43AM
Nice!
That is some pretty neat code you have going on there :)
24 Jan 11, 09:04AM
So normal/bump mapping will be impossible to do with this lighting?
24 Jan 11, 09:13AM
No, bumpmapping/parallaxmapping is another technology. They are CPU hungry.
If you want parallax/bump - play cube 2.
24 Jan 11, 01:52PM
The main principle of AC - to be simple and fast. I think there will never be slow visual effects.
24 Jan 11, 05:03PM
I think it looks great, but if implemented the lighting would have to be redone in a lot of maps.
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