1 files changed, 3 insertions, 29 deletions
diff --git a/common/shaders/math/sdf_shapes.wgsl b/common/shaders/math/sdf_shapes.wgsl
index 64df4fc..4dcfdd6 100644
--- a/common/shaders/math/sdf_shapes.wgsl
+++ b/common/shaders/math/sdf_shapes.wgsl
@@ -23,34 +23,8 @@ fn sdBox2D(p: vec2<f32>, b: vec2<f32>) -> f32 {
     return length(max(d, vec2<f32>(0.0))) + min(max(d.x, d.y), 0.0);
 }
 
+// Approximate
 fn sdEllipse(p: vec2<f32>, ab: vec2<f32>) -> f32 {
-    var p_abs = abs(p);
-    if (p_abs.x > p_abs.y) {
-        p_abs = vec2<f32>(p_abs.y, p_abs.x);
-    }
-    let l = ab.y * ab.y - ab.x * ab.x;
-    let m = ab.x * p_abs.x / l;
-    let n = ab.y * p_abs.y / l;
-    let m2 = m * m;
-    let n2 = n * n;
-    let c = (m2 + n2 - 1.0) / 3.0;
-    let c3 = c * c * c;
-    let d = c3 + m2 * n2;
-    let g = m + m * n2;
-    var co: f32;
-    if (d < 0.0) {
-        let h = acos((c3 + m2 * n2 * 2.0) / c3) / 3.0;
-        let s = cos(h);
-        let t = sin(h) * sqrt(3.0);
-        co = (sqrt(-c * (s + t * 2.0) + m2) + sign(l) * sqrt(-c * (s - t * 2.0) + m2) + abs(g) / (sqrt(-c * (s + t * 2.0) + m2) * sqrt(-c * (s - t * 2.0) + m2)) - m) / 2.0;
-    } else {
-        let h = 2.0 * m * n * sqrt(d);
-        let s = sign(c3 + m2 * n2 + h) * pow(abs(c3 + m2 * n2 + h), 1.0 / 3.0);
-        let u = sign(c3 + m2 * n2 - h) * pow(abs(c3 + m2 * n2 - h), 1.0 / 3.0);
-        let rx = -s - u + m2 * 2.0;
-        let ry = (s - u) * sqrt(3.0);
-        co = (ry / sqrt(sqrt(rx * rx + ry * ry) - rx) + 2.0 * g / sqrt(rx * rx + ry * ry) - m) / 2.0;
-    }
-    let si = sqrt(max(0.0, 1.0 - co * co));
-    return length(p_abs - vec2<f32>(ab.x * co, ab.y * si)) * sign(p_abs.y * ab.x * co - p_abs.x * ab.y * si);
+    let d = length(p / ab);
+    return length(p) * (1.0 - 1.0 / d);
 }