#version 120

uniform highp vec3 lightPosition_wrld;
uniform highp vec3 color_mdl;
uniform highp float lightStrength;
uniform highp float ambientStrength;

varying highp vec3 position_wrld;
varying highp vec3 normal_cmr;
varying highp vec3 eyeDirection_cmr;
varying highp vec3 lightDirection_cmr;
varying highp vec2 coords_mdl;

void main() {
    highp vec3 materialDiffuseColor = vec3(coords_mdl.y * color_mdl.x, coords_mdl.y * color_mdl.y, coords_mdl.y * color_mdl.z);
    highp vec3 materialAmbientColor = vec3(ambientStrength, ambientStrength, ambientStrength) * materialDiffuseColor;
    highp vec3 materialSpecularColor = vec3(1.0, 1.0, 1.0);

    highp float distance = length(lightPosition_wrld - position_wrld);
    highp vec3 n = normalize(normal_cmr);
    highp vec3 l = normalize(lightDirection_cmr);
    highp float cosTheta = clamp(dot(n, l), 0.0, 1.0);

    highp vec3 E = normalize(eyeDirection_cmr);
    highp vec3 R = reflect(-l, n);
    highp float cosAlpha = clamp(dot(E, R), 0.0, 1.0);

    gl_FragColor.rgb =
        materialAmbientColor +
        materialDiffuseColor * lightStrength * (cosTheta * cosTheta) / (distance * distance) +
        materialSpecularColor * lightStrength * pow(cosAlpha, 5) / (distance * distance);
}