out vec4 FragColor;

uniform float uTime;
uniform vec3 uCam;
uniform vec2 uInvRes;
uniform vec4 uColour;

in vec3 aNorm;
in vec2 aUv;
in vec3 aCo;

void main()
{
   vec2 ssuv = gl_FragCoord.xy;
   float opacity = 1.0-smoothstep(0.0,1.0,aUv.y+uColour.a);
   
   vec3 vDither = vec3( dot( vec2( 171.0, 231.0 ), ssuv) );
   float dither = fract( vDither.g / 71.0 ) - 0.5;

   if( opacity+dither<0.5 )
      discard;

   FragColor = uColour;
}