first commit

shader/drand48.frag

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+#version 450 core
+
+layout(location = 0) out vec4 FragColor;
+
+/* returns a varying number between 0 and 1 */
+float drand48(vec2 co) 
+{
+  return 2 * fract(sin(dot(co.xy, vec2(12.9898,78.233))) * 43758.5453) - 1;
+}
+
+void main()
+{
+    float gray=drand48(gl_FragCoord.xy);
+
+    FragColor=vec4(vec3(gray),1.0);
+}