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shader/functions.glsl

@@ -0,0 +1,11 @@
+float closestPointOnLineParam (vec2 a, vec2 b, vec2 p) {
+  return dot(p - a,b-a) / dot(b-a,b-a);
+}
+vec2 closestPointOnSeg (vec2 a,vec2 b, vec2 p) {
+  float x = closestPointOnLineParam(a,b,p);
+  if (x < 0) {
+      return a;
+  } else{ if (x > 1) { return b; }
+      { return a + (x * (b- a));}
+  }
+}