#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 *= 64.0;
	tc.y *= 64.0;

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

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

	float a = dist(v_position.xy, vec2(0.0, 0.0)) * 2.0f;

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



/*
	vec3 col;
	vec4 tex = texture(u_texture, v_texcoord);
	vec3 norm = normalize(v_normal);
	vec3 dir = normalize(vec3(5.0, 0.25, -5.0) - v_position);
	float diff = max(dot(norm, dir), 0.0);
	float alpha = get_fog_factor(distance(u_campos, v_position));

	vec3 diffuse = diff * vec3(0.8, 0.75, 0.7);
	float ff = 1.75;
	if (diffuse.x > 0.0) diffuse.x *= ff;
	if (diffuse.y > 0.0) diffuse.y *= ff;
	if (diffuse.z > 0.0) diffuse.z *= ff;
	vec3 ambient = vec3(0.3, 0.3, 0.3);
	col = (ambient + diffuse) * tex.rgb;
	col *= mix(vec4(1.0), vec4(0.0f, 0.0, 0.0, 1.0), alpha-0.2).xyz;

	*/
//	vec4 tex = texture(u_texture, v_texcoord);
//	v_output = tex * vec4(vec3(1.5), 1.0);
}