Noise node (#1848)

* Add a noise generator node

* Cleanup

* Correctly name CMakeLists.txt

* Typo

app/shaders/noise.frag

@@ -0,0 +1,38 @@
+uniform float time_in;
+varying vec2 ove_texcoord;
+
+uniform float strength_in;
+uniform bool color_in;
+//uniform bool blend;
+
+// precision lowp    float;
+
+float PHI = 1.61803398874989484820459 * 00000.1; // Golden Ratio   
+float PI  = 3.14159265358979323846264 *  00000.1; // PI
+float SQ2 = 1.41421356237309504880169 * 10000.0; // Square Root of Two
+
+bool isNan( float val )
+{
+  return ( val < 0.0 || 0.0 < val || val == 0.0 ) ? false : true;
+  // important: some nVidias failed to cope with version below.
+  // Probably wrong optimization.
+  /*return ( val <= 0.0 || 0.0 <= val ) ? false : true;*/
+
+  // Taken from: https://stackoverflow.com/questions/11810158/how-to-deal-with-nan-or-inf-in-opengl-es-2-0-shaders
+}
+
+float gold_noise(vec2 coordinate, float seed){
+    float value = fract(tan(distance(coordinate*(seed+PHI), vec2(PHI, PI)))*SQ2)*(strength_in*0.01);
+	return isNan(value) ? 0.0 : value;
+}
+
+void main(void) {
+	vec3 noise;
+	if (color_in) {
+		noise = vec3(gold_noise(ove_texcoord, time_in + 42069.0), gold_noise(ove_texcoord, time_in + 69220.0), gold_noise(ove_texcoord, time_in + 1337.0));
+	} else {
+		noise = vec3(gold_noise(ove_texcoord, time_in + 69420.0));
+	}
+
+    gl_FragColor = vec4(noise, 1.0);
+}