Add matrix-but-its-a-circle.glsl

matrix-but-its-a-circle.glsl

@@ -0,0 +1,35 @@
+
+#ifdef GL_ES
+precision mediump float;
+#extension GL_OES_standard_derivatives : enable
+#endif
+
+uniform float time;
+uniform vec2 mouse;
+uniform vec2 resolution;
+
+// ----------------------------------------------------------------------------------------------------
+
+// variation of https://www.shadertoy.com/view/MscXWM
+// in the taste of http://9gag.com/gag/am9peXo
+
+#define TAU 6.283185307179586
+#define A  26.*fract(time*0.0002)*a + time
+#define d  O += 0.1*(1.+cos(A)) / length(vec2( fract(a*k*150./TAU)-.5, 16.*(length(U)-.1*k*sin(A)-1.5*k))); a += TAU;
+#define c d d d k+=0.65*k;
+
+void mainImage( out vec4 O, vec2 U, vec2 iResolution )
+{
+	U = (U+U-(O.xy=iResolution.xy))/O.x;
+	float a = atan(U.x,U.y), k=0.125;
+	O -= O;
+	c c c c
+		O *= O;
+	O.y = length(O);
+}
+
+// ----------------------------------------------------------------------------------------------------
+
+void main( void ) {
+	mainImage( gl_FragColor, gl_FragCoord.xy, resolution );
+}