From e8c0a474ef001caaede8e955d1f99f3d6c542e8d Mon Sep 17 00:00:00 2001
From: chai <chaifix@163.com>
Date: Thu, 6 Sep 2018 20:35:03 +0800
Subject: *update

---
 shader/metaball.shader | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 shader/metaball.shader

(limited to 'shader/metaball.shader')

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
-- 
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