From 1d89df9e2a03c72a1b5789b066128555fc086d82 Mon Sep 17 00:00:00 2001
From: Christoph Helma <helma@in-silico.ch>
Date: Wed, 12 Jul 2017 21:19:22 +0200
Subject: initial stdin parsing

---
 shader.frag | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 shader.frag

(limited to 'shader.frag')

diff --git a/shader.frag b/shader.frag
new file mode 100644
index 0000000..cf44e70
--- /dev/null
+++ b/shader.frag
@@ -0,0 +1,34 @@
+#ifdef GL_ES
+precision mediump float;
+#endif
+
+uniform vec2 resolution;
+uniform float time;
+uniform float color;
+
+float box(in vec2 _st, in vec2 _size){
+    _size = vec2(0.5) - _size*0.5;
+    vec2 uv = smoothstep(_size,
+                        _size+vec2(0.001),
+                        _st);
+    uv *= smoothstep(_size,
+                    _size+vec2(0.001),
+                    vec2(1.0)-_st);
+    return uv.x*uv.y;
+}
+
+float cross(in vec2 _st, float _size){
+    return  box(_st, vec2(_size,_size/4.)) + 
+            box(_st, vec2(_size/4.,_size));
+}
+
+void main(){
+    vec2 st = gl_FragCoord.xy/resolution.xy;
+    vec3 c = vec3(0.);
+
+    c += vec3(cross(st,0.5*abs(cos(time))));
+    c.r -= color;
+    //c *= u_color;
+
+    gl_FragColor = vec4(c,1.0);
+}
-- 
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