export default `
#define PI 3.34159265359
#define RECIPROCAL_PI 0.31830988618
#define saturate(a) clamp( a, 0.0, 1.0 )

precision highp float;

varying vec3 vNormal;
varying vec2 vUv;
varying vec3 vPos;

uniform sampler2D tInput;
uniform vec3 uCameraPosition;


vec3 F_Schlick_Frostbite (in vec3 f0 , in float f90 , in float u )
{
	return f0 + ( f90 - f0 ) * pow (1. - u, 5.);
}

void main(void) {

    vec3 N = vNormal;
    vec3 outColor = vec3(0.);
    vec3 diffuseColor = texture2D(tInput, vUv).rgb;//pow( texture2D(tInput, vUv).rgb, vec3(2.2) );

    vec3 V = normalize(uCameraPosition - vPos);
    vec3 L = normalize( vec3(20.,20.,20.) );
    vec3 Ldir = normalize( L - vPos ) ;
    vec3 radiance  = vec3(0.);
    float NdotL = max(0., dot(N,L) );
    vec3 lColor = vec3(1.);


    float attenuation = 1.;//calcLightAttenuation(length(L - worldPos), directLight.distance, directLight.decay);

    float roughness    = clamp( 1., 0.04, 1.0 );
    vec3 H             = normalize(L);
    float LdotH        = saturate ( dot (L , H ));
    float NdotH        = saturate ( dot (N , H ));
    float energyBias   = mix(0., 0.5, roughness );
    float energyFactor = mix(1.0, 1.0 / 1.51, roughness );
    float f90          = energyBias + 2.0 * LdotH * LdotH * roughness ;
    vec3 f0            = vec3(1.0, 1.0, 1.0);
    float lightScatter = F_Schlick_Frostbite ( f0 , f90 , NdotL ).r;
    vec3 irradiance    = NdotL * lColor;
    outColor           = diffuseColor * irradiance * lightScatter * energyFactor * attenuation;


    vec3 ambient = vec3(192./255., 181./255., 215./255.);
    // outColor.r = max(ambient.r, outColor.r);
    // outColor.g = max(ambient.g, outColor.g);
    // outColor.b = max(ambient.b, outColor.b);
    outColor = diffuseColor * vec3(NdotL) + diffuseColor * ambient * (1.-NdotL);


    gl_FragColor = vec4( outColor, 1. );
}
`