349 lines
7.9 KiB
GLSL
349 lines
7.9 KiB
GLSL
// https://www.shadertoy.com/view/wsjBD3
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// License CC0: A battered alien planet
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// Been experimenting with space inspired shaders
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#define PI 3.141592654
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#define TAU (2.0*PI)
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#define TOLERANCE 0.00001
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#define MAX_ITER 65
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#define MIN_DISTANCE 0.01
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#define MAX_DISTANCE 9.0
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const vec3 skyCol1 = vec3(0.35, 0.45, 0.6);
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const vec3 skyCol2 = vec3(0.4, 0.7, 1.0);
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const vec3 skyCol3 = pow(skyCol1, vec3(0.25));
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const vec3 sunCol1 = vec3(1.0,0.6,0.4);
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const vec3 sunCol2 = vec3(1.0,0.9,0.7);
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const vec3 smallSunCol1 = vec3(1.0,0.5,0.25)*0.5;
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const vec3 smallSunCol2 = vec3(1.0,0.5,0.25)*0.5;
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const vec3 mountainColor = 1.0*sqrt(vec3(0.95, 0.65, 0.45));
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const float cellWidth = 1.0;
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const vec4 planet = vec4(80.0, -20.0, 100.0, 50.0)*1000.0;
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void rot(inout vec2 p, float a) {
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float c = cos(a);
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float s = sin(a);
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p = vec2(p.x*c + p.y*s, -p.x*s + p.y*c);
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}
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vec2 mod2(inout vec2 p, vec2 size) {
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vec2 c = floor((p + size*0.5)/size);
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p = mod(p + size*0.5,size) - size*0.5;
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return c;
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}
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float circle(vec2 p, float r) {
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return length(p) - r;
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}
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float egg(vec2 p, float ra, float rb) {
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const float k = sqrt(3.0);
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p.x = abs(p.x);
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float r = ra - rb;
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return ((p.y<0.0) ? length(vec2(p.x, p.y )) - r :
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(k*(p.x+r)<p.y) ? length(vec2(p.x, p.y-k*r)) :
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length(vec2(p.x+r,p.y )) - 2.0*r) - rb;
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}
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vec2 hash(vec2 p) {
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p = vec2(dot (p, vec2 (127.1, 311.7)), dot (p, vec2 (269.5, 183.3)));
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return -1. + 2.*fract (sin (p)*43758.5453123);
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}
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vec2 raySphere(vec3 ro, vec3 rd, vec4 sphere) {
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vec3 center = sphere.xyz;
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float radius = sphere.w;
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vec3 m = ro - center.xyz;
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float b = dot(m, rd);
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float c = dot(m, m) - radius*radius;
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if(c > 0.0 && b > 0.0) return vec2(-1.0, -1.0);
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float discr = b * b - c;
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if(discr < 0.0) return vec2(-1.0);
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float normalMultiplier = 1.0;
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float s = sqrt(discr);
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float t0 = -b - s;
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float t1 = -b + s;;
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return vec2(t0, t1);
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}
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float noise1(vec2 p) {
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vec2 n = mod2(p, vec2(cellWidth));
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vec2 hh = hash(sqrt(2.0)*(n+1000.0));
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hh.x *= hh.y;
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float r = 0.225*cellWidth;
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float d = circle(p, 2.0*r);
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float h = hh.x*smoothstep(0.0, r, -d);
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return h*0.25;
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}
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float noise2_(vec2 p) {
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vec2 n = mod2(p, vec2(cellWidth));
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vec2 hh = hash(sqrt(2.0)*(n+1000.0));
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hh.x *= hh.y;
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rot(p, TAU*hh.y);
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float r = 0.45*cellWidth;
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// float d = circle(p, 1.0*r);
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float d = egg(p, 0.75*r, 0.5*r*abs(hh.y));
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float h = (hh.x)*smoothstep(0.0, r, -2.0*d);
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return h*0.275;
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}
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float height(vec2 p, float dd, int mx) {
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const float aa = 0.45;
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const float ff = 2.03;
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const float tt = 1.2;
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const float oo = 3.93;
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const float near = 0.25;
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const float far = 0.65;
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float a = 1.0;
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float o = 0.2;
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float s = 0.0;
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float d = 0.0;
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int i = 0;
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for (; i < 4;++i) {
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float nn = a*noise2_(p);
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s += nn;
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d += abs(a);
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p += o;
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a *= aa;
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p *= ff;
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o *= oo;
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rot(p, tt);
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}
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float lod = s/d;
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float rdd = dd/MAX_DISTANCE;
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mx = int(mix(float(4), float(mx), step(rdd, far)));
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for (; i < mx; ++i) {
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float nn = a*noise1(p);
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s += nn;
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d += abs(a);
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p += o;
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a *= aa;
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p *= ff;
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o *= oo;
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rot(p, tt);
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}
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float hid = (s/d);
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return mix(hid, lod, smoothstep(near, far, rdd));
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}
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float loheight(vec2 p, float d) {
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return height(p, d, 0);
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}
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float height(vec2 p, float d) {
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return height(p, d, 6);
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}
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float hiheight(vec2 p, float d) {
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return height(p, d, 8);
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}
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vec3 normal(vec2 p, float d) {
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vec2 eps = vec2(0.00125, 0.0);
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vec3 n;
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n.x = (hiheight(p - eps.xy, d) - hiheight(p + eps.xy, d));
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n.y = 2.0*eps.x;
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n.z = (hiheight(p - eps.yx, d) - hiheight(p + eps.yx, d));
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return normalize(n);
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}
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const float stepLength[] = float[](0.9, 0.25);
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float march(vec3 ro, vec3 rd, out int max_iter) {
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float dt = 0.1;
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float d = MIN_DISTANCE;
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int currentStep = 0;
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float lastd = d;
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for (int i = 0; i < MAX_ITER; ++i)
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{
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vec3 p = ro + d*rd;
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float h = height(p.xz, d);
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if (d > MAX_DISTANCE) {
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max_iter = i;
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return MAX_DISTANCE;
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}
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float hd = p.y - h;
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if (hd < TOLERANCE) {
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++currentStep;
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if (currentStep >= stepLength.length()) {
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max_iter = i;
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return d;
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}
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d = lastd;
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continue;
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}
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float sl = stepLength[currentStep];
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dt = max(hd, TOLERANCE)*sl + 0.0025*d;
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lastd = d;
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d += dt;
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}
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max_iter = MAX_ITER;
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return MAX_DISTANCE;
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}
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vec3 sunDirection() {
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return normalize(vec3(-0.5, 0.085, 1.0));
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}
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vec3 smallSunDirection() {
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return normalize(vec3(-0.2, -0.05, 1.0));
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}
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float psin(float f) {
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return 0.5 + 0.5*sin(f);
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}
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vec3 skyColor(vec3 ro, vec3 rd) {
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vec3 sunDir = sunDirection();
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vec3 smallSunDir = smallSunDirection();
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float sunDot = max(dot(rd, sunDir), 0.0);
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float smallSunDot = max(dot(rd, smallSunDir), 0.0);
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float angle = atan(rd.y, length(rd.xz))*2.0/PI;
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vec3 skyCol = mix(mix(skyCol1, skyCol2, max(0.0, angle)), skyCol3, clamp(-angle*2.0, 0.0, 1.0));
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vec3 sunCol = 0.5*sunCol1*pow(sunDot, 20.0) + 8.0*sunCol2*pow(sunDot, 2000.0);
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vec3 smallSunCol = 0.5*smallSunCol1*pow(smallSunDot, 200.0) + 8.0*smallSunCol2*pow(smallSunDot, 20000.0);
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vec3 dust = pow(sunCol2*mountainColor, vec3(1.75))*smoothstep(0.05, -0.1, rd.y)*0.5;
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vec2 si = raySphere(ro, rd, planet);
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vec3 planetSurface = ro + si.x*rd;
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vec3 planetNormal = normalize(planetSurface - planet.xyz);
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float planetDiff = max(dot(planetNormal, sunDir), 0.0);
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float planetBorder = max(dot(planetNormal, -rd), 0.0);
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float planetLat = (planetSurface.x+planetSurface.y)*0.0005;
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vec3 planetCol = mix(1.3*vec3(0.9, 0.8, 0.7), 0.3*vec3(0.9, 0.8, 0.7), pow(psin(planetLat+1.0)*psin(sqrt(2.0)*planetLat+2.0)*psin(sqrt(3.5)*planetLat+3.0), 0.5));
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vec3 final = vec3(0.0);
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final += step(0.0, si.x)*pow(planetDiff, 0.75)*planetCol*smoothstep(-0.075, 0.0, rd.y)*smoothstep(0.0, 0.1, planetBorder);
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final += skyCol + sunCol + smallSunCol + dust;
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return final;
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}
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vec3 getColor(vec3 ro, vec3 rd) {
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int max_iter = 0;
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vec3 skyCol = skyColor(ro, rd);
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vec3 col = vec3(0);
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float d = march(ro, rd, max_iter);
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if (d < MAX_DISTANCE) {
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vec3 sunDir = sunDirection();
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vec3 osunDir = sunDir*vec3(-1.0, .0, -1.0);
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vec3 p = ro + d*rd;
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vec3 normal = normal(p.xz, d);
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float amb = 0.2;
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float dif1 = max(0.0, dot(sunDir, normal));
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vec3 shd1 = sunCol2*mix(amb, 1.0, pow(dif1, 0.75));
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float dif2 = max(0.0, dot(osunDir, normal));
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vec3 shd2 = sunCol1*mix(amb, 1.0, pow(dif2, 0.75));
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vec3 ref = reflect(rd, normal);
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vec3 rcol = skyColor(p, ref);
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col = mountainColor*amb*skyCol3;
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col += mix(shd1, shd2, -0.5)*mountainColor;
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float fre = max(dot(normal, -rd), 0.0);
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fre = pow(1.0 - fre, 5.0);
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col += rcol*fre*0.5;
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col += (1.0*p.y);
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col = tanh(col);
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col = mix(col, skyCol, smoothstep(0.5*MAX_DISTANCE, 1.0*MAX_DISTANCE, d));
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} else {
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col = skyCol;
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}
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// col += vec3(1.1, 0.0, 0.0)* smoothstep(0.25, 1.0,(float(max_iter)/float(MAX_ITER)));
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return col;
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}
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vec3 getSample1(vec2 p, float time) {
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float off = 0.5*iTime;
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vec3 ro = vec3(0.5, 1.0-0.25, -2.0 + off);
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vec3 la = ro + vec3(0.0, -0.30, 2.0);
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vec3 ww = normalize(la - ro);
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vec3 uu = normalize(cross(vec3(0.0,1.0,0.0), ww));
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vec3 vv = normalize(cross(ww, uu));
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vec3 rd = normalize(p.x*uu + p.y*vv + 2.0*ww);
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vec3 col = getColor(ro, rd) ;
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return col;
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}
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vec3 getSample2(vec2 p, float time) {
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p.y-=time*0.25;
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float h = height(p, 0.0);
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vec3 n = normal(p, 0.0);
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vec3 lp = vec3(10.0, -1.2, 0.0);
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vec3 ld = normalize(vec3(p.x, h, p.y)- lp);
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float d = max(dot(ld, n), 0.0);
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vec3 col = vec3(0.0);
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col = vec3(1.0)*(h+0.1);
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col += vec3(1.5)*pow(d, 0.75);
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return col;
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}
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void mainImage(out vec4 fragColor, vec2 fragCoord) {
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vec2 q = fragCoord.xy/iResolution.xy;
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vec2 p = -1.0 + 2.0*q;
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p.x *= iResolution.x/iResolution.y;
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vec3 col = getSample1(p, iTime);
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fragColor = vec4(col, 1.0);
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}
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