khanat-assets---3d-godot-cl.../shaders/sky.shader
2019-10-08 15:44:51 +02:00

194 lines
5 KiB
GLSL

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