1 files changed, 19 insertions, 0 deletions
diff --git a/assets/ball_f.glsl b/assets/ball_f.glsl
new file mode 100644
index 0000000..e3dfdb3
--- /dev/null
+++ b/assets/ball_f.glsl
@@ -0,0 +1,19 @@
+varying vec4 color;
+varying vec2 pos;
+uniform vec2 center;
+uniform float radius;
+
+void main() {
+	float dist_squared = dot(pos - center, pos - center);
+	float threshold = 0.9 * radius; // radius border starts at
+	float thickness = radius - threshold;
+
+	if (dist_squared > threshold * threshold && dist_squared < radius * radius) {
+		float dist = sqrt(dist_squared);
+		float v = (dist - threshold) / thickness;
+		v = 2.0 * v - 1.0;
+		gl_FragColor = color * (1.0 - v * v);
+	} else {
+		discard;
+	}
+}