#version 330 core

uniform vec3 u_campos;

in vec3 v_position;
in vec3 v_normal;
in vec2 v_texcoord;

layout (location=0) out vec4 v_output;

uniform sampler2D u_texture;

float get_fog_factor(float d)
{
	const float FogMax = 10.0;
	const float FogMin = 0.0;

	if (d >= FogMax) return 1.0;
	if (d <= FogMin) return 0.0;

	return 1 - (FogMax - d) / (FogMax - FogMin);
}

struct Light
{
  vec3 position;
  vec3 diffuse;
};

float lambert(vec3 n, vec3 l)
{
	vec3 nrmn = normalize(n);
	vec3 nrml = normalize(l);
	float res = dot(nrmn, nrml);
	return max(res, 0.0);
}

float dist(vec2 p0, vec2 pf){return sqrt((pf.x-p0.x)*(pf.x-p0.x)+(pf.y-p0.y)*(pf.y-p0.y));}

void main()
{
    Light light;
	light.position = vec3(0.0, 0.0, 0.0);
	light.diffuse = vec3(1.0, 1.0, 1.0);

	vec2 tc = v_texcoord;
	tc.x = (v_texcoord.x)+u_campos.x/1000.0;          //mod(u_campos.x/1024.0, 10.0);
	tc.y = (v_texcoord.y)+u_campos.z/1000.0;          //mod(u_campos.z/1024.0, 10.0);

	tc.x *= 1000.0;
	tc.y *= 1000.0;

	vec4 tex = texture(u_texture, tc);
	vec3 norm = normalize(v_normal);
	

	vec3 res = light.diffuse * lambert(norm, light.position);

	float a = dist(v_position.xz, vec2(0.0, 0.0)) * 25.0f;

	tex.rgb *= 1.0 - a;

	v_output = vec4(tex.rgb, tex.a);
}