#version 120

uniform mat2 m = mat2(1.);

void main()
{
	vec2 cartesian_PointCoord = m * ((gl_PointCoord * -2.0) + vec2(1.0));
	vec2 len_sq = cartesian_PointCoord * cartesian_PointCoord;
	len_sq.y /= 2.0;
	if (len_sq.x + len_sq.y < 0.5) {
		gl_FragColor = vec4(1.0);
	} else {
		discard;
	}
}