#version 430 core


#define EPS 0.01


///////////////////////////////////////////////////////////////////////////////
// shader inputs/outputs
///////////////////////////////////////////////////////////////////////////////
uniform float iGlobalTime; // in seconds
uniform vec2 iResolution; // viewport resolution (in pixels) (1080p or 720p)
uniform mat4 iMidiPad; // 16 buttons of midi controller
uniform float iMidiPadValue; // sum of all elements in iMidiPad/16

// all samplers have linear filtering applied, wraping set to repeat
//
uniform sampler1D iFFTTexture; // 1024
uniform float iFFT[8]; // latest frame
uniform float iFFTs[8]; // smoothed latest frame
uniform sampler2D iFFTsHistory; // smoothed fft history, 8x1024, x coord = bin, y coord n-frames earlier, y=0 is latest frame

// predefined textures
//
uniform sampler2D iTex1;
uniform sampler2D iTex2;
uniform sampler2D iTex3;
uniform sampler2D iTex4;
uniform sampler2D iTex5;
uniform sampler2D iTex6;
uniform sampler2D iTex7;
uniform sampler2D iTex8;
uniform sampler2D iNoise;
uniform sampler2D iChecker;

// out_color must be written in order to see anything
//
layout(location = 0) out vec4 out_color;
///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////


vec4 gMaterial = vec4(0.0);



vec3 rx(vec3 v, float a) {

	mat2 m = mat2( cos(a), sin(a), -sin(a), cos(a) );



	v.yz = m * v.yz;

	return v;

}



vec4 sel(float d1, vec4 m1, float d2, vec4 m2) {

	float f = floor(sign(d1 - d2) * 0.5 + 0.5);

	return mix(m1,m2,f);

}



float s(vec3 p) {

	vec3 pp = p - vec3( 0.0,1.5 - iFFT[0] * 2.0,0.0 );



	pp = rx(pp,iGlobalTime);



	float sp = length(pp) - 0.5;

	float pl = p.y;



	vec3 c1 = vec3(1.0,0.0,0.0);

	vec3 c2 = vec3(1.0);



	float as = atan(pp.z,pp.x);

	as = mod(as / 3.14159265 * 6.0, 2.0);



	vec3 c = vec3(0.0);

	if(as > 1.0 && mod(asin(pp.y) * 6.0, 2.0) > 1.0)

		c = c2;

	else

		c = c1;



	if(as < 1.0 && mod(asin(pp.y) * 6.0, 2.0) < 1.0)

		c = c1;

	else

		c = c2;

	



	gMaterial = sel(

		sp, vec4(c,0.0),

		pl, vec4(0.0,0.5,1.0,0.0)

	);



	return min(sp,pl);

}



bool rm(vec3 ro, vec3 rd, int steps, out vec3 hit)

{

	vec3 p = ro;

	for(int i = 0; i < steps; ++i) {

		float d = s(p);



		if(d < EPS) {

			hit = p;

			return true;

		}



		p += rd * d;

		if(distance(p,ro)>100.0) break;

	}



	return false;

}



vec3 no(vec3 p) {

	vec2 e = vec2(EPS,0.0);

	return normalize(vec3(

		s(p+e.xyy)-s(p-e.xyy),

		s(p+e.yxy)-s(p-e.yxy),

		s(p+e.yyx)-s(p-e.yyx)

	));

}



vec2 ph(vec3 p, vec3 n, vec3 e, vec3 lp, float lr) {

	vec3 N = normalize(n);

	vec3 L = normalize(lp - p);

	vec3 V = normalize(e - p);

	vec3 H = normalize(L + V);



	return vec2(

		max(0.0, dot(N, L)),

		max(0.0, pow(dot(N, H), 128.0))

	);

}


void main(void)
{
	vec2 uv = vec2( gl_FragCoord.xy ) / iResolution;

	vec2 q=uv*2.0-vec2(1.0);



	vec3 ro = vec3(0.0,5.0,5.0);

	vec3 rd = normalize(vec3(q*vec2(1.6,0.9),-1.5));

	rd = rx(rd,-0.7);



	out_color = vec4(0.0,uv.y*0.5,uv.y*0.8+0.2,1.0);



	vec3 lp = vec3(0.0,8.0,0.0);



	vec3 hit;

	if(rm(ro,rd,128,hit))

	{

		vec2 li = ph(hit,no(hit),ro,lp,15.0);

		out_color.rgb=vec3(gMaterial.rgb * li.x + vec3(li.y));

	}
}