Draw ellipses and make them rotateHEADmaster

1 files changed, 8 insertions, 1 deletions

diff --git a/data/ellipse.frag b/data/ellipse.frag
index bf35027..2436f28 100644
--- a/data/ellipse.frag
+++ b/data/ellipse.frag
@@ -4,5 +4,12 @@ uniform mat2 m = mat2(1.);
 
 void main()
 {
-	gl_FragColor = vec4(1.0);
+	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;
+	}
 }