frukt.glsl

#ifdef GL_ES
precision mediump float;
#endif

#extension GL_OES_standard_derivatives : enable

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


vec4 orb = vec4(1000.0); 
	
float aspect_ratio = resolution.y / resolution.x;
float ray_scale = (1. / max(resolution.x, resolution.y)) * 0.1;


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;
		
			 orb = min( orb, vec4(abs(p),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 raymarch(in vec3 from, in vec3 dir) {
	
	float maxd = 30.0;
    float t = 0.01;
    for( int i=0; i<200; i++ )
    {
	    float precis = 0.001 * t;
        
	    float h = de( from+dir*t) ;
			 
        if( h<precis||t>maxd ) break;
        t += h;
    }

    if( t>maxd ) t=-1.0;
    return t;;
}


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

float shadow( in vec3 ro, in vec3 rd)
{
	float res = 1.0;
    	float t = 0.05;
	float h;
	
    	for (int i = 0; i < 8; i++){
		h = de( ro + rd*t );
		res = min(6.0*h / t, res);
		t += h;
	}
    	return max(res, 0.0);
}

void main( void ) {

	
	vec2 uv = (gl_FragCoord.xy / resolution) - .5;
	/*
	vec3 camPos = .2*time*vec3(1.0,0.,0.0);	
	
	vec3 lookAt = camPos + vec3(1.,0.0*cos(time),0.);
	vec3 camUp  = vec3(1.0,0,1.);
	vec3 camDir   = normalize(lookAt-camPos); 
	
	camUp = normalize(camUp-dot(camDir,camUp)*camDir); 
	vec3 camRight = normalize(cross(camDir,camUp));

	vec3 rd =  normalize(camDir + (uv.x*camRight + uv.y*camUp)*1.5); ;//vec3(uv.x * fov, uv.y * fov * aspect_ratio, 1.0);


	vec3 ro =  camPos;

	*/
	float fov = 1.;
	
	
	vec3 col = vec3(0.0);
	
	vec3 rd = vec3(uv.x * fov, uv.y * fov * aspect_ratio, 1.0);

	vec3 ro =  .3*time*vec3(0.,0.3,1.5);

	
	float t = raymarch(ro,rd);
	
	
	if(t > 0.0){
		
     	vec3 pos = ro + t*rd;
  	vec4 tra = orb;
        
        vec3 nor = normal( pos);

        // lighting
        vec3  light1 = vec3(  0.577, 0.577, -0.577 );
        vec3  light2 = vec3( -0.707, 0.000,  0.707 );
        float key = clamp( dot( light1, nor ), 0.0, 1.0 );
        float bac = clamp( 0.2 + 0.8*dot( light2, nor ), 0.0, 1.0 );
        float amb = (0.7+0.3*nor.y);
        float ao = pow( clamp(tra.w*2.0,0.0,1.0), 1.2 );

        vec3 brdf  = 1.0*vec3(0.40,0.40,0.40)*amb*ao;
        brdf += 1.0*vec3(1.00,1.00,1.00)*key*ao;
        brdf += 1.0*vec3(0.40,0.40,0.40)*bac*ao;

        // material		
        vec3 rgb = vec3(0.0);
        rgb = mix( rgb, vec3(1.0,0.80,0.2), clamp(6.0*tra.y,0.0,1.0) );
        rgb = mix( rgb, vec3(1.0,0.55,0.0), pow(clamp(1.0-2.0*tra.z,0.0,1.0),8.0) );

        // color
        col = rgb*brdf*exp(-0.2*t);
	
	col = sqrt(col);
	}
	

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

}