out vec2 uvs;
out vec2 pixcoord;
out vec4 offset[3];

void main()
{
  int v = gl_VertexID % 3;
  float x = -1.0 + float((v & 1) << 2);
  float y = -1.0 + float((v & 2) << 1);
  gl_Position = vec4(x, y, 1.0, 1.0);
  uvs = (gl_Position.xy + 1.0) * 0.5;

#if SMAA_STAGE == 0
  SMAAEdgeDetectionVS(uvs, offset);
#elif SMAA_STAGE == 1
  SMAABlendingWeightCalculationVS(uvs, pixcoord, offset);
#elif SMAA_STAGE == 2
  SMAANeighborhoodBlendingVS(uvs, offset[0]);
#endif
}