#define MAX_NUM 128
#define ITERATIONS 10000
//随机数设置，直接参考的IQ
vec2 rand( inout uint seed )
{
seed = seed*0x343fdU + 0x269ec3U; uint x = seed;
seed = seed*0x343fdU + 0x269ec3U; uint y = seed;
return vec2( (uvec2(x,y)>>16)&32767U)/32767.0;
}
vec2 p2c( in vec2 p )
{
vec2 q = p/iResolution.xy;
q = -1.0 + 2.0*q;
q.x *= iResolution.x/iResolution.y;
return (q - vec2(0.5,0.0))*1.1;
}
float Mandelbrot(vec2 p)
{
vec2 z= vec2(0.0,0.0);
int i=0;
for(;i<MAX_NUM && dot(z,z)<1e4;i++)
z=vec2(z.x*z.x-z.y*z.y,2.*z.x*z.y)+p;
if(i==MAX_NUM)
return 0.0;
else
return 1.0;
}
float Budhabrot(vec2 p)
{
float k=0.0;
for(int i=0;i<ITERATIONS;i++)
{
if(Mandelbrot(p)<1.0);
else k=k+1.0;
}
return k;
}
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
//随机数设置，直接参考的IQ
uvec2 p = uvec2(fragCoord-0.5);
uint seed = uint(iFrame)*512U*8U + p.y*1920U+p.x;
seed ^= (seed<<13);
vec2 c = vec2(0.0);
for( int i=0; i<32; i++ )
{
vec2 of = rand(seed);
c = p2c( of*iResolution.xy)*1.1;
// test H1 and H2
float c2 = dot(c,c);
vec2 d = c + vec2(1.0,0.0);
float h1 = 256.0*c2*c2 - 96.0*c2 + 32.0*c.x - 3.0;
float h2 = 16.0*dot(d,d) - 1.0;
if( h1>0.0 && h2>0.0 ) break;
}
float k=0.0;
k=Budhabrot(c);
vec3 col=pow(0.5,k)*0.3+vec3(0.1,0.1,0.1);
// Output to screen
fragColor = vec4(col,1.0);
}
