Untitled

#version 330

uniform samplerCube skyboxTex;
uniform mat4 MV;
uniform vec3 cameraPosition;

const float radius = 0.5f;
const vec3 lightPosition = vec3(0.0f, 10.0f, 0.0f);

const vec3 colorDiffuse = vec3(0.2f, 0.45f, 0.89f);

const vec3 colorSpecular = vec3(1.0f);
const float shininess = 10.0f;

const float refractIndex = 1.0f/1.3333f;

in vec4 fPosition;

out vec4 fColor;

void main(void)
{
    vec3 N;
    N.xy = gl_PointCoord * 2.0f - 1.0f;
    float r2 = dot(N.xy,N.xy);
    if(r2 > 1.0f) discard;
    N.z = sqrt(1.0f - r2);
    N = normalize(N);

    // View-space fragment's position
    vec3 position = fPosition.xyz + N*radius;

    // Light direction - from surface to light
    vec3 L = normalize(lightPosition - position);
    // Incident light direction - from light to surface
    vec3 Ilight = -L;
    // Reflect incident light direction around the normal
    vec3 Rlight = reflect(Ilight,N);
    // View direction - from surface to camera
    vec3 V = normalize(cameraPosition - position);
    // Incident view direction - from camera to surface
    vec3 Iview = -V;
    // Reflect incident view direction around the normal
    vec3 Rl_view = -reflect(Iview,N);
    // Refract incident view direction around the normal
    vec3 Rr_view = refract(Iview,N,refractIndex);

    float diffuse = max(0.0f, dot(L,N));
    float specular = 0.0f;
    if(diffuse > 0.0f)
        specular = pow(max(0.0f, dot(V,Rlight)),shininess);

    fColor = vec4(diffuse*colorDiffuse, 1.0f);
    //fColor = vec4(specular*colorSpecular + diffuse*colorDiffuse, 1.0f);
    //fColor = texture(skyboxTex,Rview);
    //fColor = texture(skyboxTex,Rr_view);
}