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ledbanner-shaders/eye-of-sauron.glsl
polyfloyd ae07b0daf8 Add WIP shaders
2018-05-19 17:23:49 +02:00

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// Eye of Sauron. By Dave Hoskins. Dec. 2013
// Video: http://youtu.be/DCQrDLbhiuQ
#pragma map iChannel0=builtin:RGBA Noise Medium
#define TAU 6.28318530718
#define MOD2 vec2(.16632,.17369)
#define MOD3 vec3(.16532,.17369,.15787)
float gTime = 0;
float flareUp = 0;
//=================================================================================================
vec2 Rotate2axis(vec2 p, float a)
{
float si = sin(a);
float co = cos(a);
return mat2(si, co, -co, si) * p;
}
//=================================================================================================
// Linear step, faster than smoothstep...
float LinearStep(float a, float b, float x)
{
return clamp((x-a)/(b-a), 0.0, 1.0);
}
//=================================================================================================
float Hash(float p)
{
vec2 p2 = fract(vec2(p) * MOD2);
p2 += dot(p2.yx, p2.xy+19.19);
return fract(p2.x * p2.y);
}
//=================================================================================================
float EyeNoise( in float x )
{
float p = floor(x);
float f = fract(x);
f = clamp(pow(f, 7.0), 0.0,1.0);
//f = f*f*(3.0-2.0*f);
return mix(Hash(p), Hash(p+1.0), f);
}
//=================================================================================================
float Bump( in vec3 x )
{
vec3 p = floor(x);
vec3 f = fract(x);
//f = f*f*(3.0-2.0*f);
vec2 uv = (p.xy + vec2(37.0, 17.0) * p.z) + f.xy;
vec2 rg = textureLod( iChannel0, (uv+.5)/256., 0.).yx;
return mix(rg.x, rg.y, f.z);
}
//=================================================================================================
float Noise( in vec3 x )
{
vec3 p = floor(x);
vec3 f = fract(x);
f = f*f*(3.0-2.0*f);
vec2 uv = (p.xy + vec2(37.0, 17.0) * p.z) + f.xy;
vec2 rg = textureLod( iChannel0, (uv+.5)/256., 0.).yx;
return mix(rg.x, rg.y, f.z);
}
//=================================================================================================
float Pupil(vec3 p, float r)
{
// It's just a stretched sphere but the mirrored
// halves are push together to make a sharper top and bottom.
p.xz = abs(p.xz)+.25;
return length(p) - r;
}
//=================================================================================================
float DE_Fire(vec3 p)
{
p *= vec3(1.0, 1.0, 1.5);
float len = length(p);
float ax = atan(p.y, p.x)*10.0;
float ay = atan(p.y, p.z)*10.0;
vec3 shape = vec3(len*.5-gTime*1.2, ax, ay) * 2.0;
shape += 2.5 * (Noise(p * .25) -
Noise(p * 0.5) * .5 +
Noise(p * 2.0) * .25);
float f = Noise(shape)*6.0;
f += (LinearStep(7.30, 8.3+flareUp, len)*LinearStep(12.0+flareUp*2.0, 8.0, len)) * 3.0;
p *= vec3(.75, 1.2, 1.0);
len = length(p);
f = mix(f, 0.0, LinearStep(12.5+flareUp, 16.5+flareUp, len));
return f;
}
//=================================================================================================
float Sphere(vec3 p, float r)
{
return length(p) - r;
}
//=================================================================================================
float DE_Pillars(vec3 p)
{
// It's just two spheres with added bumpy noise.
// Simple, but it'll do fine. :)
float d = Sphere((p+vec3(0.0, 1.0, 0.0))*vec3(1.0, 1.0, 18.0), 20.0);
d = max(-Sphere((p + vec3(0.0, -3.0, 38.0))* vec3(1.5, 1.1, .95), 44.0), d);
d += Noise(p*2.0)*.15 + Noise(p*8.0)*.04;
return d;
}
//=================================================================================================
float DE_Pupil(vec3 p)
{
float time = gTime * .5+sin(gTime*.3)*.5;
float t = EyeNoise(time) * .125 +.125;
p.yz = Rotate2axis(p.yz, t * TAU);
p *= vec3(1.2-EyeNoise(time+32.5)*.5, .155, 1.0);
t = EyeNoise(time-31.0) * .125 +.1875;
p.xz = Rotate2axis(p.xz, t*TAU);
p += vec3(.0, 0.0, 4.);
float d = Pupil(p, .78);
return d * max(1.0, abs(p.y*2.5));
}
//=================================================================================================
vec3 Normal( in vec3 pos )
{
vec2 eps = vec2( 0.1, 0.0);
vec3 nor = vec3(
DE_Pillars(pos+eps.xyy) - DE_Pillars(pos-eps.xyy),
DE_Pillars(pos+eps.yxy) - DE_Pillars(pos-eps.yxy),
DE_Pillars(pos+eps.yyx) - DE_Pillars(pos-eps.yyx) );
return normalize(nor);
}
//=================================================================================================
vec4 Raymarch( in vec3 ro, in vec3 rd, in vec2 fragCoord, inout bool hit, out float pupil)
{
float sum = 0.0;
// Starting point plus dither to prevent edge banding...
float t = 14.0 + .1 * texture(iChannel0, fragCoord.xy / iChannelResolution[0].xy).y;
vec3 pos = vec3(0.0, 0.0, 0.0);
float d = 100.0;
pupil = 0.0;
for(int i=0; i < 197; i++)
{
if (t > 37.0) break;
pos = ro + t*rd;
vec3 shape = pos * vec3(1.5, .4, 1.5);
// Accumulate pixel denisity depending on the distance to the pupil
d = DE_Pupil(pos);
pupil += LinearStep(0.02 +Noise(pos*4.0+gTime)*.3, 0.0, d) * .17;
// Add fire around pupil...
sum += LinearStep(1.3, 0.0, d) * .014;
// Search for pillars...
d = DE_Pillars(pos);
if (d < 0.01)
{
pos = ro + (t + d) * rd;
hit = true;
break;
}
sum += max(DE_Fire(pos), 0.0) * .00162;
t += max(.1, t*.0057);
}
return vec4(pos, clamp(sum*sum*sum, 0.0, 1.0 ));
}
//=================================================================================================
vec3 FlameColour(float f)
{
f = f*f*(3.0-2.0*f);
return min(vec3(f+.8, f*f*1.4+.05, f*f*f*.6) * f, 1.0);
}
//=================================================================================================
float Sky(vec2 p)
{
float z = gTime*.5 + 47.5;
p *= .0025;
float dist = length(p) * .7;
float f = 0.0;
float w = .27;
for (int i=0; i < 7; i++)
{
f += Noise(vec3(p, z)) * w;
w *= .55;
p *= 2.7;
}
f = smoothstep(.17, 1.0, f)*.55;
f = f / dist;
return f;
}
//=================================================================================================
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
gTime = iTime + 44.29;
flareUp = max(sin(gTime*.75+3.5), 0.0);
vec2 uv = fragCoord.xy / iResolution.xy;
vec2 p = -1.0 + 2.0 * uv;
p.x *= iResolution.x/iResolution.y;
vec3 origin = vec3(sin(gTime*.34)*5.0, -10.0 - sin(gTime*.415) * 6.0, -20.0+sin(gTime*.15) * 2.0);
vec3 target = vec3( 0.0, 0.0, 0.0 );
// Make camera ray using origin and target positions...
vec3 cw = normalize( target-origin);
vec3 cp = vec3(0.0, 1.0, 0.0);
vec3 cu = normalize( cross(cw, cp) );
vec3 cv = ( cross(cu,cw) );
vec3 ray = normalize(p.x*cu + p.y*cv + 1.5 * cw );
bool hit = false;
float pupil = 0.0;
vec4 ret = Raymarch(origin, ray, fragCoord, hit, pupil);
vec3 col = vec3(0.0);
vec3 light = vec3(0.0, 4.0, -4.0);
// Do the lightning flash effect...
float t = mod(gTime+3.0, 13.0);
float flash = smoothstep(0.4, .0, t);
flash += smoothstep(0.2, .0, abs(t-.6)) * 1.5;
flash += smoothstep(0.7, .8, t) * smoothstep(1.3, .8, t);
flash *= 2.2;
if (hit)
{
// Pillars...
vec3 nor = Normal(ret.xyz);
vec3 ldir = normalize(light - ret.xyz);
vec3 ref = reflect(ray, nor);
float bri = max(dot(ldir, nor), 0.0) * (1.0+flareUp*2.0) + flash * max(nor.y * 2.0 - nor.z*.5, 0.0);
float spe = max(dot(ldir, ref), 0.0);
spe = pow(abs(spe), 40.0) * .15;
vec3 mat = vec3(.6, .4, .35) * .15;
col = mat * bri + spe * vec3(.4, .2, .0);
}else
{
// Background...
if (ray.y > 0.0)
{
float d = (250.0 - origin.y) / ray.y;
vec2 cloud = vec2((ray * d).xz);
float k = Sky(cloud);
col = vec3(.7, .7, 1.0) * k;
col += (smoothstep(0.045, 0.19, k)) * flash * vec3(.58, .53, .6);
}
}
col += FlameColour(ret.w);
col = mix (col, vec3(0.0), min(pupil, 1.0));
// Contrasts...
col = sqrt(col);
col = min(mix(vec3(length(col)),col, 1.22), 1.0);
col += col * .3;
fragColor = vec4(min(col, 1.0),1.0);
}
// https://www.shadertoy.com/view/ldBGWW
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