some lighting experiement - ice sculptures

#version 330 core

uniform vec3 lightPos;

in vec3 modelPos;
in vec3 faceNormal;

// Code adpated from opengl-tutorial.org
void main() {
    vec3 n = normalize(faceNormal);
    vec3 l = normalize(lightPos);

    // Cosine of the angle between the normal and the light direction,
    // clamped above 0
    //  - light is at the vertical of the triangle -> 1
    //  - light is perpendicular to the triangle -> 0
    //  - light is behind the triangle -> 0
    float cosTheta = clamp(dot(n, l), 0, 1);
    float distance = abs(modelPos - lightPos);

    vec3 diffuseColor = vec3(137/255, 183/255, 255/255);
    vec3 lightColor = vec3(1,1,1);
    float lightPower = 60;
    vec3 color = diffuseColor * lightColor * lightPower * cosTheta / (distance*distance);
    gl_FragColor = color;

    //float lv = dot(normal, lightPos);
    //float corrected = pow(lv, 1.0 / 2.2);
    //gl_FragColor = vec4(137.0 / 255.0, 183.0 / 255.0, 1.0, 1.0);
    //gl_FragColor = vec4(corrected, corrected, corrected, 1.0);
}