#version 330 core

#include <constants.glsl>

#define LIGHTING_TYPE LIGHTING_TYPE_REFLECTION

#define LIGHTING_REFLECTION_KIND LIGHTING_REFLECTION_KIND_GLOSSY

#if (FLUID_MODE == FLUID_MODE_CHEAP)
#define LIGHTING_TRANSPORT_MODE LIGHTING_TRANSPORT_MODE_IMPORTANCE
#elif (FLUID_MODE == FLUID_MODE_SHINY)
#define LIGHTING_TRANSPORT_MODE LIGHTING_TRANSPORT_MODE_RADIANCE
#endif

#define LIGHTING_DISTRIBUTION_SCHEME LIGHTING_DISTRIBUTION_SCHEME_MICROFACET

#define LIGHTING_DISTRIBUTION LIGHTING_DISTRIBUTION_BECKMANN

#include <globals.glsl>
#include <srgb.glsl>
#include <lod.glsl>

in uint v_pos_norm;
in uint v_col_light;

layout (std140)
uniform u_locals {
	vec3 model_offs;
	float load_time;
};

out vec3 f_pos;
out vec3 f_chunk_pos;
flat out uint f_pos_norm;
// out float f_alt;
// out vec4 f_shadow;
out vec3 f_col;
out float f_light;
out float f_ao;

const int EXTRA_NEG_Z = 32768;

void main() {
    // over it (if this vertex to see if it intersects.
	f_chunk_pos = vec3(ivec3((uvec3(v_pos_norm) >> uvec3(0, 6, 12)) & uvec3(0x3Fu, 0x3Fu, 0xFFFFu)) - ivec3(0, 0, EXTRA_NEG_Z));
	f_pos = f_chunk_pos + model_offs;

	// f_pos.z -= 250.0 * (1.0 - min(1.0001 - 0.02 / pow(tick.x - load_time, 10.0), 1.0));
	// f_pos.z -= min(32.0, 25.0 * pow(distance(focus_pos.xy, f_pos.xy) / view_distance.x, 20.0));

	f_col = vec3((uvec3(v_col_light) >> uvec3(8, 16, 24)) & uvec3(0xFFu)) / 255.0;

	f_light = float(v_col_light & 0x3Fu) / 64.0;
	f_ao = float((v_col_light >> 6u) & 3u) / 4.0;

	f_pos_norm = v_pos_norm;

    // Also precalculate shadow texture and estimated terrain altitude.
    // f_alt = alt_at(f_pos.xy);
    // f_shadow = textureBicubic(t_horizon, pos_to_tex(f_pos.xy));

    // IDEA: Cast a ray from the vertex to the camera (if this vertex is above the camera) or from the camera to the vertex (if this
    // vertex is below the camera) to see where it intersects the plane of water.  All of this only applies if either the terrain
    // vertex is in water, or the camera is in water.
    //
    // If an intersection is found, refract the ray across the barrier using the correct ratio of indices of refraction (1 / N_WATER
    // if the vertex is above the camera [ray is going from air to water], N_WATER if the camera is above the vertex
    // [ray is going from water to air]).
    //
    // In order to make sure that terrain and other objects below such an interface are properly renered, we then "un-refract" by
    // reversing the refracted vector, and multiplying that by the distance from the object from which we cast the ray to the
    // intersectng point, in order to make the object appear to the viewer where it should after refraction.
    // bool faces_fluid = bool((f_pos_norm >> 28) & 0x1u);
    // // TODO: Measure real water surface altitude here.
    // float surfaceAlt = faces_fluid ? max(ceil(f_pos.z), floor(f_alt)) : /*floor(f_alt);*/mix(view_distance.z, min(f_alt, floor(alt_at_real(cam_pos.xy))), medium.x);

    // vec3 wRayinitial = f_pos; // cam_pos.z < f_pos.z ? f_pos : cam_pos.xyz;
    // vec3 wRayfinal = cam_pos.xyz; // cam_pos.z < f_pos.z ? cam_pos.xyz : f_pos;
    // vec3 wRayNormal = surfaceAlt < wRayinitial.z ? vec3(0.0, 0.0, 1.0) : vec3(0.0, 0.0, -1.0);
    // float n_camera = mix(1.0, 1.3325, medium.x);
    // float n_vertex = faces_fluid ? 1.3325 : 1.0;
    // float n1 = n_vertex; // cam_pos.z < f_pos.z ? n_vertex : n_camera;
    // float n2 = n_camera; // cam_pos.z < f_pos.z ? n_camera : n_vertex;

    // float wRayLength0 = length(wRayfinal - wRayinitial);
    // vec3 wRayDir = (wRayfinal - wRayinitial) / wRayLength0;
    // vec3 wPoint = wRayfinal;
    // bool wIntersectsSurface = IntersectRayPlane(wRayinitial, wRayDir, vec3(0.0, 0.0, surfaceAlt), -wRayNormal, wPoint);
    // float wRayLength = length(wPoint - wRayinitial);
    // wPoint = wRayLength < wRayLength0 ? wPoint : wRayfinal;
    // wRayLength = min(wRayLength, wRayLength0); // min(max_length, dot(wRayfinal - wpos, defaultpos - wpos));

    // // vec3 wRayDir2 = (wRayfinal - wRayinitial) / wRayLength;

    // vec3 wRayDir3 = (dot(wRayDir, wRayNormal) < 0.0 && wIntersectsSurface) ? refract(wRayDir, wRayNormal, n2 / n1) : wRayDir;
    // // wPoint -= wRayDir3 * wRayLength * n2 / n1;
    // vec3 newRay = dot(wRayDir, wRayNormal) < 0.0 && wIntersectsSurface ? wPoint - wRayDir3 * wRayLength * n2 / n1 : f_pos;// - (wRayfinal - wPoint) * n2 / n1; // wPoint + n2 * (wRayfinal - wPoint) - n2 / n1 * wRayLength * wRayDir3;

	gl_Position =
		all_mat *
		vec4(f_pos/*newRay*/, 1);
	// gl_Position.z = -gl_Position.z / 100.0;
	gl_Position.z = -1000.0 / (gl_Position.z + 10000.0);
}