1 files changed, 15 insertions, 0 deletions
diff --git a/shader/metaball.shader b/shader/metaball.shader
new file mode 100644
index 0000000..e7e344e
--- /dev/null
+++ b/shader/metaball.shader
@@ -0,0 +1,15 @@
+extern vec2 distortionFactor;
+extern vec2 scaleFactor;
+extern number feather;
+vec4 effect(vec4 color, Texture tex, vec2 uv, vec2 px) {
+  // to barrel coordinates
+  uv = uv * 2.0 - vec2(1.0);
+  // distort
+  uv *= scaleFactor;
+  uv += (uv.yx*uv.yx) * uv * (distortionFactor - 1.0);
+  number mask = (1.0 - smoothstep(1.0-feather,1.0,abs(uv.x)))
+              * (1.0 - smoothstep(1.0-feather,1.0,abs(uv.y)));
+  // to cartesian coordinates
+  uv = (uv + vec2(1.0)) / 2.0;
+  return color * Texel(tex, uv) * mask;
+}
+\ No newline at end of file