// shader.frag
#version 450

struct Material {
    vec4 albedo;
};

// Variables
layout(location=0) in vec2 vert_uv;
layout(location=0) out vec4 out_color;

layout(set=0,binding=0) uniform Uniforms {
    mat4 _ViewMatrix;
    mat4 _ProjMatrixInv;
    vec3 _CamPos;
    vec3 _SunDir;
    float _Time;
};
layout(set=1,binding=0) uniform usampler3D _NodesTexture;
layout(set=2,binding=0) uniform usampler3D _BricksTexture;
layout(set=3, binding=0) uniform Materials {
    Material _Materials[256];
};

// Defines
// #define PI 3.141592
// #define EPSILON 0.01
// #define NEAR 0.01

// Include
#include "structs.cginc"
#include "shading.cginc"
#include "raycasting.cginc"


void main() 
{
    // Black by default
    out_color = vec4(0,0,0,1);

    // Calculate ray direction
    vec3 view_dir = (_ProjMatrixInv * vec4(vert_uv, 0, 1)).xyz;
    vec3 ray_dir = normalize(_ViewMatrix * vec4(view_dir,0)).xyz;

    // Raycast
    HitResult primary = castNodes(_CamPos, ray_dir);
    if(primary.data > 0)
    {
        out_color = vec4(applyLighting(primary.pos, ray_dir, primary.normal, primary.data), 1.0);

        HitResult shadow = castNodes(primary.pos-ray_dir*0.000001, _SunDir);
        if(shadow.data > 0) out_color *= 0.1;
    }
    else
    {
        float up = clamp(dot(ray_dir, vec3(0, 1, 0)) + 0.1, 0, 1);
        vec3 sky = vec3(0.176, 0.592, 0.901) * up;
        out_color = vec4(sky, 1.0);
    }
}