uniform float time;
uniform float seed;
uniform vec2 resolution;
uniform vec2 cursor;
uniform vec2 scroll;
uniform float transition;
vec4 bgCol=vec4(.1,0.,.0,1.);
vec4 grainCol=vec4(1.);
vec3 hash(vec3 p){
p=vec3(dot(p,vec3(127.1,311.7,74.7)),
dot(p,vec3(269.5,183.3,246.1)),
dot(p,vec3(113.5,271.9,124.6)));
return-1.+2.*fract(sin(p)*43758.5453123);
}
float noise(in vec3 p){
vec3 i=floor(p);
vec3 f=fract(p);
vec3 u=f*f*(3.-2.*f);
return mix(mix(mix(dot(hash(i+vec3(0.,0.,0.)),f-vec3(0.,0.,0.)),
dot(hash(i+vec3(1.,0.,0.)),f-vec3(1.,0.,0.)),u.x),
mix(dot(hash(i+vec3(0.,1.,0.)),f-vec3(0.,1.,0.)),
dot(hash(i+vec3(1.,1.,0.)),f-vec3(1.,1.,0.)),u.x),u.y),
mix(mix(dot(hash(i+vec3(0.,0.,1.)),f-vec3(0.,0.,1.)),
dot(hash(i+vec3(1.,0.,1.)),f-vec3(1.,0.,1.)),u.x),
mix(dot(hash(i+vec3(0.,1.,1.)),f-vec3(0.,1.,1.)),
dot(hash(i+vec3(1.,1.,1.)),f-vec3(1.,1.,1.)),u.x),u.y),u.z);
}
float fbm(in vec2 st,in int octaves){
float value=0.;
float amp=.6;
float freq=0.;
for(int i=0;i<octaves;i++){
value+=amp*noise(vec3(st,time));
st*=2.1;
amp*=.35;
}
return value;
}
float expImpulse(float x,float k){
float h=k*x;
return h*exp(1.-h);
}
float sdBox(in vec2 p,in vec2 b){
vec2 d=abs(p)-b;
return length(max(d,0.))+min(max(d.x,d.y),0.);
}
void grain(inout vec4 col,inout vec2 uv){
col=mix(col,grainCol,hash(vec3(uv,1.)).x*.03);
}
void flames(inout vec4 col,inout vec2 uv){
float nt=sin(time/5.)*2.-1.;
float amt=pow(pow((fbm(uv*6.,8)*.5+.5),5.)*sdBox(uv,vec2(.5))*100.,(1.-nt)*3.)-nt*2.;
col=vec4(vec3(1.,.25,.08)/amt,1.);
}
void main(){
float aspect=min(resolution.y/resolution.x,1.);
vec4 col=bgCol;
vec2 uv=gl_FragCoord.xy;
uv-=resolution*.5;
uv/=resolution.x*aspect*.35;
flames(col,uv);
grain(col,uv);
gl_FragColor=col;
}
