194 lines
5 KiB
GLSL
194 lines
5 KiB
GLSL
shader_type canvas_item;
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// USING https://www.shadertoy.com/view/XtBXDw (base on it)
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uniform float iTime;
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uniform int iFrame;
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uniform sampler2D iChannel0;
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uniform float COVERAGE :hint_range(0,1); //0.5
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uniform float THICKNESS :hint_range(0,100); //25.
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uniform float ABSORPTION :hint_range(0,10); //1.030725
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uniform int STEPS :hint_range(0,100); //25
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float noise( in vec3 x )
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{
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x*=0.01;
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float z = x.z*256.0;
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vec2 offz = vec2(0.317,0.123);
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vec2 uv1 = x.xy + offz*floor(z);
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vec2 uv2 = uv1 + offz;
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return mix(textureLod( iChannel0, uv1 ,0.0).x,textureLod( iChannel0, uv2 ,0.0).x,fract(z));
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}
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float fbm(vec3 pos,float lacunarity){
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vec3 p = pos;
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float
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t = 0.51749673 * noise(p); p *= lacunarity;
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t += 0.25584929 * noise(p); p *= lacunarity;
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t += 0.12527603 * noise(p); p *= lacunarity;
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t += 0.06255931 * noise(p);
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return t;
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}
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float get_noise(vec3 x)
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{
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float FBM_FREQ=2.76434;
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return fbm(x, FBM_FREQ);
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}
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vec3 render_sky_color(vec3 rd){
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vec3 sun_color = vec3(1., .7, .55);
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vec3 SUN_DIR = normalize(vec3(0, abs(sin( .3)), -1));
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float sun_amount = max(dot(rd, SUN_DIR), 0.0);
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vec3 sky = mix(vec3(.0, .1, .4), vec3(.3, .6, .8), 1.0 - rd.y);
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sky = sky + sun_color * min(pow(sun_amount, 1500.0) * 5.0, 1.0);
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sky = sky + sun_color * min(pow(sun_amount, 10.0) * .6, 1.0);
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return sky;
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}
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bool SphereIntersect(vec3 SpPos, float SpRad, vec3 ro, vec3 rd, out float t, out vec3 norm) {
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ro -= SpPos;
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float A = dot(rd, rd);
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float B = 2.0*dot(ro, rd);
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float C = dot(ro, ro)-SpRad*SpRad;
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float D = B*B-4.0*A*C;
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if (D < 0.0) return false;
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D = sqrt(D);
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A *= 2.0;
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float t1 = (-B+D)/A;
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float t2 = (-B-D)/A;
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if (t1 < 0.0) t1 = t2;
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if (t2 < 0.0) t2 = t1;
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t1 = min(t1, t2);
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if (t1 < 0.0) return false;
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norm = ro+t1*rd;
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t = t1;
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//norm = normalize(norm);
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return true;
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}
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float density(vec3 pos,vec3 offset,float t){
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vec3 p = pos * .0212242 + offset;
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float dens = get_noise(p);
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float cov = 1. - COVERAGE;
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dens *= smoothstep (cov, cov + .05, dens);
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return clamp(dens, 0., 1.);
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}
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vec4 render_clouds(vec3 ro,vec3 rd){
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vec3 apos=vec3(0, -450, 0);
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float arad=500.;
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vec3 WIND=vec3(0, 0, -iTime * .2);
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vec3 C = vec3(0, 0, 0);
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float alpha = 0.;
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vec3 n;
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float tt;
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if(SphereIntersect(apos,arad,ro,rd,tt,n)){
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float thickness = THICKNESS;
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int steps = STEPS;
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float march_step = thickness / float(steps);
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vec3 dir_step = rd / rd.y * march_step;
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vec3 pos =n;
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float T = 1.;
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for (int i = 0; i < steps; i++) {
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float h = float(i) / float(steps);
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float dens = density (pos, WIND, h);
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float T_i = exp(-ABSORPTION * dens * march_step);
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T *= T_i;
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if (T < .01) break;
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C += T * (exp(h) / 1.75) *dens * march_step;
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alpha += (1. - T_i) * (1. - alpha);
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pos += dir_step;
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if (length(pos) > 1e3) break;
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}
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return vec4(C, alpha);
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}
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return vec4(C, alpha);
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}
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float fbm2(in vec3 p)
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{
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float f = 0.;
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f += .50000 * noise(.5 * (p+vec3(0.,0.,-iTime*0.275)));
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f += .25000 * noise(1. * (p+vec3(0.,0.,-iTime*0.275)));
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f += .12500 * noise(2. * (p+vec3(0.,0.,-iTime*0.275)));
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f += .06250 * noise(4. * (p+vec3(0.,0.,-iTime*0.275)));
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return f;
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}
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vec3 cube_bot(vec3 d, vec3 c1, vec3 c2)
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{
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return fbm2(d) * mix(c1, c2, d * .5 + .5);
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}
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vec3 rotate_y(vec3 v, float angle)
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{
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float ca = cos(angle); float sa = sin(angle);
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return v*mat3(
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vec3(+ca, +.0, -sa),
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vec3(+.0,+1.0, +.0),
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vec3(+sa, +.0, +ca));
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}
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vec3 rotate_x(vec3 v, float angle)
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{
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float ca = cos(angle); float sa = sin(angle);
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return v*mat3(
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vec3(+1.0, +.0, +.0),
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vec3(+.0, +ca, -sa),
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vec3(+.0, +sa, +ca));
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}
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void panorama_uv(vec2 fragCoord, out vec3 ro,out vec3 rd, in vec2 iResolution){
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float M_PI = 3.1415926535;
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float ymul = 2.0; float ydiff = -1.0;
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vec2 uv = fragCoord.xy / iResolution.xy;
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uv.x = 2.0 * uv.x - 1.0;
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uv.y = ymul * uv.y + ydiff;
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ro = vec3(0., 5., 0.);
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rd = normalize(rotate_y(rotate_x(vec3(0.0, 0.0, 1.0),-uv.y*M_PI/2.0),-uv.x*M_PI));
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}
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void mainImage( out vec4 fragColor, in vec2 fragCoord, in vec2 iResolution)
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{
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vec3 ro = vec3 (0.,0.,0.);
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vec3 rd = vec3(0.);
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vec3 col=vec3(0.);
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panorama_uv(fragCoord,ro,rd,iResolution);
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vec3 sky = render_sky_color(rd);
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vec4 cld = vec4(0.);
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float skyPow = dot(rd, vec3(0.0, -1.0, 0.0));
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float horizonPow =1.-pow(1.0-abs(skyPow), 5.0);
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if(rd.y>0.)
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{cld=render_clouds(ro,rd);
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cld=clamp(cld,vec4(0.),vec4(1.));
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cld.rgb+=0.04*cld.rgb*horizonPow;
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cld*=clamp(( 1.0 - exp(-2.3 * pow(max((0.0), horizonPow), (2.6)))),0.,1.);
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}
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else{
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cld.rgb = cube_bot(rd,vec3(1.5,1.49,1.71), vec3(1.1,1.15,1.5));
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cld*=cld;
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//cld=clamp(cld,vec4(0.),vec4(1.));
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cld.a=1.;
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cld*=clamp(( 1.0 - exp(-1.3 * pow(max((0.0), horizonPow), (2.6)))),0.,1.);
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}
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col=mix(sky, cld.rgb/(0.0001+cld.a), cld.a);
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//col*=col;
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fragColor = vec4(col,1.0);
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}
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void fragment(){
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vec2 iResolution=1./TEXTURE_PIXEL_SIZE;
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mainImage(COLOR,UV*iResolution,iResolution);
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}
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