#version 430 core
layout (points) in;
layout (triangle_strip, max_vertices = 4) out;

uniform vec2 lightPos;
uniform mat4 worldMat;

void emitLine (vec2 pa)
{
    gl_Position = vec4 (pa, 0, 1);
    EmitVertex();
    gl_Position = vec4 (pa + (200 * (pa - lightPos)), 0 , 1);
    EmitVertex();
}

void main()
{
  vec4 frontL4 = worldMat * vec4(gl_in[0].gl_Position.xy, 0 ,1);
  vec4 frontR4 = worldMat * vec4(gl_in[0].gl_Position.zw, 0 ,1);
  vec2 frontL = frontL4.xy;
  vec2 frontR = frontR4.xy;

    emitLine (frontR);
    emitLine (frontL);
  EndPrimitive();
}