#version 100

precision mediump float;


varying float  lightDiffuse;

void main()
{
    float light = ( 1.0 - lightDiffuse) * 0.5;
    vec3 lightColor = vec3(0.0,1.0,1.0);
    vec3 diffuseColor = lightColor * light ;

    vec4 c;
    if(lightDiffuse <0.0 )
    {
        // back faces, opaque
       // front faces, very transparent
        c  = vec4(diffuseColor, 0.2);

    }
    else
    {
        discard;

    }

    gl_FragColor = c;

}




#version 100
#define lowp
#define mediump
#define highp

attribute vec4 vertex;
attribute vec3 normal;


uniform mat4 normalMatrix;
uniform mat4 modelViewProjectionMatrix;
uniform mat4 modelView;
uniform vec3 camera_world_position;

varying highp float lightDiffuse;

void main()
{
	gl_Position = modelViewProjectionMatrix * vertex;

  vec3 norm = normal;
  norm *=-1.0;
  lightDiffuse = dot(normalize(vec3(norm.x, norm.y, norm.z)), normalize(camera_world_position));


}