bark.glsl

#ifdef GL_ES
precision mediump float;
#endif

#extension GL_OES_standard_derivatives : enable

uniform float time;
uniform vec2 mouse;
uniform vec2 resolution;


float aspect_ratio = resolution.y / resolution.x;
float ray_scale = (1. / max(resolution.x, resolution.y)) * .47;
float fov = 1.7;





float de( vec3 p )
{	
	p = abs(1.0-mod(p,2.0));
	float scale = 2.0;
	for( int i=0; i<7;i++ )
	{
		p = -1.0 + 2.0*fract(0.5*p+0.5);
		float r2 = dot(p,p);
		float k = 1.0/r2;
		p     *= k;
		scale *= k;
	}
	return 0.25*abs(p.y) / scale;
}

vec3 normal(in vec3 p) {
	
 	vec2 e = vec2(0.005, -0.005); 
 	return normalize(e.xyy * de(p + e.xyy) + e.yyx * de(p + e.yyx) + e.yxy * de(p + e.yxy) + e.xxx * de(p + e.xxx));
}

float detail = 0.0002;
float calcAO( const vec3 pos, const vec3 nor ) {
	float aodet=detail*80.;
	float totao = 0.0;
    	float sca = 10.0;
   	 for( int aoi=0; aoi<5; aoi++ ) {
        	float hr = aodet + aodet*float(aoi*aoi);
        	vec3 aopos =  nor * hr + pos;
        	float dd = de( aopos );
       		 totao += -(dd-hr)*sca;
        	sca *= 0.75;
    }
    return clamp( 1.0 - 5.0*totao, 0.0, 1.0 );
}





float raymarch(in vec3 from, in vec3 dir) {
		
	float l = 0.; 
	float d = 0.; 
	float e = 0.0002; 
	float it = 0.;
	
	for(int i=0;i<64;i++){
		d = de(from);
		from += d * dir;
		l += d;
		if(d<e) break;
		
		e = ray_scale * l;
		it++;	
	}	
	float f = 1. - (it / float(64));
	return f;
}

vec3 postProcess(vec3 color){
	
	color*=vec3(1.,.94,.87);
	color=pow(color,vec3(1.2));
	color=mix(vec3(length(color)),color,.85)*.95;
	
	return color;
}



void main( void ) {

	
	vec2 uv = (gl_FragCoord.xy / resolution) - .5;
	

	float fov  = 1.5;
	
	
	vec3 dir = vec3(uv.x * fov, uv.y * fov * aspect_ratio, 1.);
	
	
	vec3 cam =  .4*time*vec3(0.1,0.,0.0);
	
	vec3 backg=vec3(0);
	
		
	vec3 col = vec3(1.0);
	
	float k = raymarch(cam,dir);
	
	float l = calcAO(cam*dir,normal(dir));
	
	if(k > 0.0002){
		col*=vec3(1.,.85,.8)*.6;
		color = mix(color, backg, 1.0-exp(-1.3*pow0.5,1.3)));
		col *= k * l;
	}else{
		col = vec3(0);
	}
		
	
	
	
	
	col+=vec3(1,.85,.7)*pow(max(0.,.3-length(uv-vec2(0.,.03)))/.3,1.5)*.35;
	
	

	gl_FragColor = vec4( postProcess(col),1.);

}