ios - How to draw cropped bitmap using the Metal API or Accelerate Framework? -


i'm implementing custom video compositor crops video frames. use core graphics this:

-(void)renderimage:(cgimageref)image inbuffer:(cvpixelbufferref)destination {     cgrect croprect = // rect ...     cgimageref currentrectimage = cgimagecreatewithimageinrect(photofullimage, croprect);      size_t width = cvpixelbuffergetwidth(destination);     size_t height = cvpixelbuffergetheight(destination);      cgcontextref context = cgbitmapcontextcreate(cvpixelbuffergetbaseaddress(destination),       // data                                              width,                                              height,                                              8,                                              // bpp                                              cvpixelbuffergetbytesperrow(destination),                                              cgimagegetcolorspace(backimage),                                              cgimagegetbitmapinfo(backimage));      cgrect frame = cgrectmake(0, 0, width, height);     cgcontextdrawimage(context, frame, currentrectimage);     cgcontextrelease(context); }

how can use metal api this? should faster, right? using accelerate framework (vimage specifically)? simpler?

ok, don't know wether useful you, still. check out following code:

- (void)captureoutput:(avcaptureoutput *)captureoutput didoutputsamplebuffer:(cmsamplebufferref)samplebuffer fromconnection:(avcaptureconnection *)connection {   cvpixelbufferref pixelbuffer = cmsamplebuffergetimagebuffer(samplebuffer);    id<mtltexture> texturey = nil;    {     size_t width = cvpixelbuffergetwidth(pixelbuffer);     size_t height = cvpixelbuffergetheight(pixelbuffer);      mtlpixelformat pixelformat = mtlpixelformatbgra8unorm;      cvmetaltextureref texture = null;     cvreturn status = cvmetaltexturecachecreatetexturefromimage(null, _texturecache, pixelbuffer, null, pixelformat, width, height, 0, &texture);     if(status == kcvreturnsuccess)     {       texturey = cvmetaltexturegettexture(texture);       if (self.delegate){         [self.delegate textureupdated:texturey];       }       cfrelease(texture);     }   } }

i use code convert cvpixelbufferref mtltexture. after should create blitcommandencoder , use it's 

func copyfromtexture(sourcetexture: mtltexture, sourceslice: int, sourcelevel: int, sourceorigin: mtlorigin, sourcesize: mtlsize, totexture destinationtexture: mtltexture, destinationslice: int, destinationlevel: int, destinationorigin: mtlorigin)

in it, can select cropped rectangle , copy other texture.

the next step convert generated mtltextures cvpixelbufferrefs , make video out of that, unfortunately don't know how that.

would hear came with. cheers.


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