#version 430 core
layout (points) in;
layout (triangle_strip, max_vertices = 4) out;
in vec4 vParams [];
in vec2 vWinSize [];
out vec2 gTexPos;

void main()
{
  vec2 cPos = vec2(vParams[0].x / 250 , vParams[0].y /250 );
  float zoom = vParams[0].w;
  float xoff = vWinSize[0].x / (500*zoom) ;
  float yoff = vWinSize[0].y / (500*zoom) ;
  gTexPos = vec2 (cPos.x + xoff,cPos.y + yoff);
  gl_Position = vec4 (1,1,0.9,1);
  EmitVertex();
  gTexPos = vec2 (cPos.x + xoff,cPos.y - yoff);
  gl_Position = vec4 (1,-1,0.9,1);
  EmitVertex();
  gTexPos = vec2 (cPos.x - xoff,cPos.y + yoff);
  gl_Position = vec4 (-1,1,0.9,1);
  EmitVertex();
  gTexPos = vec2 (cPos.x - xoff,cPos.y - yoff);
  gl_Position = vec4 (-1,-1,0.9,1);
  EmitVertex();

  EndPrimitive();
}