/*
* Interpolation of input. The interp_var_at* intrinsics are similar to the
- * load_var intrinsic acting an a shader input except that they interpolate
+ * load_var intrinsic acting on a shader input except that they interpolate
* the input differently. The at_sample and at_offset intrinsics take an
- * aditional source that is a integer sample id or a vec2 position offset
+ * additional source that is an integer sample id or a vec2 position offset
* respectively.
*/