#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Mon Aug  5 15:58:30 2019

@author: pavel
"""

#vertex shader for the tube drawing
VERT_SHADER = """
// Uniforms
// ------------------------------------
uniform vec4 u_bb[26];
uniform vec3 u_LightPost;
uniform mat4 u_model;
//uniform mat4 u_view;
uniform mat4 u_projection;

uniform vec3 u_eye;
uniform vec3 u_up;
uniform vec3 u_target;

// Attributes
// ------------------------------------
attribute vec3 a_position;
attribute vec3 a_normal;
attribute vec4 a_fg_color;

// Varyings
// ------------------------------------
varying vec3 v_normal;
varying vec4 v_fg_color;
varying vec3 v_position;
varying mat4 u_view;
varying vec3 vt_position;


// Functions
// ------------------------------------

mat4 make_view(vec3 eye, vec3 target, vec3 up);

void main (void) {
    // Calculate position
    mat4 u_view = make_view(u_eye, u_target, u_up);

    mat4 MVP = u_projection * u_view * u_model;
    mat4 MV = u_view * u_model;
    v_normal = vec3(MV * vec4(a_normal, 0.0));
    v_position = vec3(MV*vec4(a_position, 1.0));
    vt_position = vec3(a_position);
    v_fg_color = a_fg_color;
    gl_Position = MVP * vec4(a_position, 1.0);
}

mat4 make_view(vec3 eye, vec3 target, vec3 up)
{
     vec3 zaxis = normalize(eye - target);
     vec3 xaxis = normalize(cross(up, zaxis));
     vec3 yaxis = cross(zaxis,  xaxis);

     mat4 viewMatrix = mat4(
        vec4(      xaxis.x,            yaxis.x,            zaxis.x,       0 ),
        vec4(      xaxis.y,            yaxis.y,            zaxis.y,       0 ),
        vec4(      xaxis.z,            yaxis.z,            zaxis.z,       0 ),
        vec4(-dot( xaxis, eye ), -dot( yaxis, eye ), -dot( zaxis, eye ),  1 )
    );

//     mat4 viewMatrix = mat4(
//        vec4(      xaxis.x,            xaxis.y,            xaxis.z,       -dot( xaxis, eye ) ),
//        vec4(      yaxis.x,            yaxis.y,            yaxis.z,       -dot( yaxis, eye ) ),
//        vec4(      zaxis.x,            zaxis.y,            zaxis.z,       -dot( zaxis, eye ) ),
//        vec4(         0,                  0,                   0,                   1)
//    );


     return viewMatrix;
}
"""

#Fragment shader for the tube drawing.
FRAG_SHADER = """
// Uniforms
// ------------------------------------
uniform vec3 u_bb[26];
uniform vec3 u_LightPos;
uniform mat4 u_model;
//uniform mat4 u_view;
uniform mat4 u_projection;

uniform vec3 u_eye;
uniform vec3 u_up;
uniform vec3 u_target;

// Varyings
// ------------------------------------
varying vec3 v_normal;
varying vec4 v_fg_color;
varying vec3 v_position;
varying mat4 u_view;
varying vec3 vt_position;

float new_alpha();
float set_view();
float bin_alpha(float alpha);

void main()
{
    //Ambient Lighting
    float ambientStrength = 0.5;
    vec4 ambient_color = ambientStrength*v_fg_color;


    mat4 MV = u_projection * u_view * u_model;
    //vec3 u_LightP = vec3(0., 0., 0.);
    vec3 u_LightP = vec3(u_eye);
    //mat4 inv = inverse(u_view);

    //vec3 u_LightP = vec3(u_view[0][3], u_view[1][3], u_view[2][3]);

    //Diffuse Lighting
    //float distance = length(u_LightP - v_position);
    vec3 norm = normalize(v_normal);
    vec3 lightVector = normalize(u_LightP - v_position);
    float diffuse = max(dot(norm, lightVector), 0.0);

    //diffuse = diffuse * (1.0 / (1.0 + (0.25 * distance * distance)));

    vec4 color = (ambient_color + diffuse)*v_fg_color;
    float alpha = new_alpha();
    //if(alpha == 1.0)
    //    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
    //    gl_FragColor = vec4(color.rgb, alpha);
    //else
        gl_FragColor = vec4(color.rgb, alpha);
    //    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
    //gl_FragColor = v_fg_color;
}

float new_alpha()
{
     float alpha = 0.0;

     //find the min and the max
     float mx = -100000.0;
     float mn = 100000.0;
     vec3 u_light = vec3(u_eye);
     for(int i = 0; i < 26; i++)
     {
          //vec3 rot_bb = vec3(u_projection * u_view * u_model * vec4(u_bb[i], 1.0));
          vec3 rot_bb = u_bb[i];
          if(length(rot_bb - u_light) < mn)
          {
              mn = length(rot_bb - u_light);
          }
          if(length(rot_bb - u_light) > mx)
          {
              mx = length(rot_bb - u_light);
          }
     }

     float l = length(u_light - vt_position);
     alpha = (l-mn)/(mx-mn);
     return bin_alpha(alpha);
//     if(alpha > 0.9)
//         return 1.0;
//     else if(alpha > 0.8)
//         return 0.9;
//     else if(alpha > 0.7)
//         return 0.8;
//     else if (alpha > 0.6)
//         return 0.7;
//     else if (alpha > 0.5)
//         return 0.6;
//     else if (alpha > 0.4)
//         return 0.5;
//     else if (alpha > 0.3)
//         return 0.4;
//     else if (alpha > 0.2)
//         return 0.3;
//     else if (alpha > 0.1)
//         return 0.2;
//    else if (alpha > 0.0)
//         return 0.0;
//     else
//         return alpha;
}

float bin_alpha(float alpha)
{

 
     if(alpha > 0.8)
         return 0.0;
     else if(alpha > 0.6)
         return 0.1;
     else if (alpha > 0.4)
         return 0.4;
     else if (alpha > 0.2)
         return 0.8;
     else if (alpha > 0.0)
         return 1.0;
     else
         return 1.0;
     
//     if(alpha > 0.9)
//         return 0.0;
//     else if(alpha > 0.8)
//         return 0.1;
//     else if(alpha > 0.7)
//         return 0.2;
//     else if (alpha > 0.6)
//         return 0.3;
//     else if (alpha > 0.5)
//         return 0.4;
//     else if (alpha > 0.4)
//         return 0.5;
//     else if (alpha > 0.3)
//         return 0.6;
//     else if (alpha > 0.2)
//         return 0.7;
//     else if (alpha > 0.1)
//         return 0.8;
//     else if (alpha > 0.0)
//         return 0.9;
//     else
//         return 1.0;
}

"""