Put everything into an ArrayBuffer and call C++ just once.
On Sat, May 16, 2020, 15:07 Feng Wang <jfwf2...@gmail.com> wrote:
> I have an image (1024x1024x3) that needs to be process pixel-by-pixel. The
> per-pixel processing code is written using javascript. I've found that it
> takes 277ms to loop through this handler in c++ code, and only 10ms to loop
> in javascript code. I want to know how to make the c++ call javascript
> function as fast as possible.
>
> //javascript per-pixel processing function
> var pixelfunction=function( rgb , index )
> {
> var outval = (rgb[0]-rgb[1]/(rgb[0]+rgb[1]) ;
> return outval;
> }
>
>
>
> //c++ codes loop call pixelfunction
> ...
> v8::Function* pixelFunc = ...; // this Function pointer is pixelfunction
> in javascript.
> v8::Local<v8::Uint8Array> vals = ...; //
> v8::Local<Value> targs[2] ;
> for(int it = 0 ;it<1024*1024;++it)
> {
> vals = ...; // get r,g,b values from image ;
> targs[0] = vals;
> targs[1] = v8::Integer::New( global , it );
> pixelFunc->Call( context , context->Global() , 2 , targs);//For
> convenience, I'm giving up the return value.
> }
> ...
>
> -
> //javascript loop call:
> var vals=new Uint8Array(3);
> for(var it = 0 ; it < 1024*1024 ; ++it )
> {
> vals=...; //get r,g,b values from image
> pixelfunction( vals , it );//For convenience, I'm giving up the return
> value.
> }
>
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