#version 450
#extension GL_GOOGLE_include_directive : enable

#include "lighting.h"

layout (input_attachment_index = 0, set = 2, binding = 0) uniform subpassInput color;
layout (input_attachment_index = 1, set = 2, binding = 1) uniform subpassInput emission;
layout (input_attachment_index = 2, set = 2, binding = 2) uniform subpassInput normal;
layout (input_attachment_index = 3, set = 2, binding = 3) uniform subpassInput position;

layout (set = 3, binding = 0) uniform sampler2DArrayShadow shadowCascade[32];
layout (set = 3, binding = 0) uniform sampler2DArrayShadow shadowPlane[32];
layout (set = 3, binding = 0) uniform samplerCubeArrayShadow shadowCube[32];

layout (location = 0) out vec4 frag_color;

layout (constant_id = 0) const int ShadowType = ST_NONE;

float
spot_cone (LightData light, vec3 incoming)
{
	vec3        dir = light.direction.xyz;
	float       cone = light.direction.w;
	float       spotdot = dot (incoming, dir);
	return 1 - smoothstep (cone, .995 * cone + 0.005, spotdot);
}

float
diffuse (vec3 incoming, vec3 normal)
{
	float       lightdot = dot (incoming, normal);
	return clamp (lightdot, 0, 1);
}

float
shadow_cascade (sampler2DArrayShadow map, uint layer, uint mat_id, vec3 pos)
{
	return 1;
}

float
shadow_plane (sampler2DArrayShadow map, uint layer, uint mat_id, vec3 pos)
{
	return 1;
}

float
shadow_cube (samplerCubeArrayShadow map, uint layer, uint mat_id, vec3 pos)
{
	return 1;
}

void
main (void)
{
	vec3        c = subpassLoad (color).rgb;
	vec3        e = subpassLoad (emission).rgb;
	vec3        n = subpassLoad (normal).rgb;
	vec3        p = subpassLoad (position).rgb;
	vec3        light = vec3 (0);

	//vec3        minLight = vec3 (0);
	for (int i = 0; i < lightCount; i++) {
		uint        id = lightIds[i];
		LightData   l = lights[id];
		vec3        dir = l.position.xyz - l.position.w * p;
		float       r2 = dot (dir, dir);
		vec4        a = l.attenuation;

		if (l.position.w * a.w * a.w * r2 >= 1) {
			continue;
		}
		vec4        r = vec4 (r2, sqrt(r2), 1, 0);
		vec3        incoming = dir / r.y;
		float       I = (1 - a.w * r.y) / dot (a, r);

		uint        id_data = renderer[id].id_data;
		uint        mat_id = bitfieldExtract (id_data, 0, 13);
		uint        map_id = bitfieldExtract (id_data, 13, 5);
		uint        layer = bitfieldExtract (id_data, 18, 11);
		if (ShadowType == ST_CASCADE) {
			I *= shadow_cascade (shadowCascade[map_id], layer, mat_id, p);
		} else if (ShadowType == ST_PLANE) {
			I *= shadow_plane (shadowPlane[map_id], layer, mat_id, p);
		} else if (ShadowType == ST_CUBE) {
			I *= shadow_cube (shadowCube[map_id], layer, mat_id, p);
		}

		float       namb = dot(l.direction.xyz, l.direction.xyz);
		I *= spot_cone (l, incoming) * diffuse (incoming, n);
		I = mix (1, I, namb);
		vec4 col = l.color;
		if (bitfieldExtract(id_data, 31, 1) == 0) {
			col *= style[renderer[id].style];
		}
		light += I * col.w * col.xyz;
	}
	//light = max (light, minLight);

	frag_color = vec4 (light, 1);
}