#version 330 core

uniform vec2 resolution;
uniform float time;

out vec3 color;

#define MAX_STEPS 100
#define MAX_DIST 100.
#define SURF_DIST .01
#define NORMAL_ACCURACY 0.01

#include "objects/sphere.frag"
float GetDist(vec3 p) {
    float sphereDist =  SphereSDF(p,vec3(0, 1, 6),1);
    float planeDist = p.y;
    
    float d = min(sphereDist, planeDist);
    return d;
}

#include "algorithms/raymarching.frag"
#include "algorithms/normal.frag"



float GetLight(vec3 p) {
    vec3 lightPos = vec3(0, 5, 6);
    lightPos.xz += vec2(sin(time), cos(time))*2.;
    vec3 l = normalize(lightPos-p);
    vec3 n = GetNormal(p);
    
    float dif = clamp(dot(n, l), 0., 1.);
    float d = RayMarch(p+n*SURF_DIST*2., l);
    if(d<length(lightPos-p)) dif *= .1;
    
    return dif;
}

void main()
{
    vec2 uv = (gl_FragCoord.xy-.5*resolution.xy)/resolution.y;

    vec3 col = vec3(0);
    
    vec3 ro = vec3(0, 1, 0);
    vec3 rd = normalize(vec3(uv.x, uv.y, 1));

    float d = RayMarch(ro, rd);
    
    vec3 p = ro + rd * d;
    
    float dif = GetLight(p);
    col = vec3(dif);
    
    col = pow(col, vec3(.4545));	// gamma correction
    
    color = col;
}