readback from gpu just for a 0 or 1?
i am wondering…:
i have a vast chain of slabs doing all sorts of complicated things very nicely… but now i need to know just wether the luminance of one of these textures in between is above or below a certain threshhold. i searched for quite a bit but it seems i really have to readback to cpu for this… do i?
i attached what i currently do below… as soon as i connect it, i get a 20 fps framedrop – even with this tiny texture.
if i really have to read back, can this been done more efficiently?
-- Pasted Max Patch, click to expand. --Copy all of the following text. Then, in Max, select New From Clipboard.----------begin_max5_patcher---------- 865.3ocuWFtbhBCDG+y5SwN7o6lokg.HT5byb8dNtoiSDRwzFRrgPq85z28K IHVsUDJR0QCxRby+7Ka1M95zINKDqIkNv0vegISdc5jIVSFCS1b+DmB75TFt z1MmTQQAgqbtn9YJxZk0NiluTQjfZIgqajjxkBVFbo96zRP+V+.PvYuXLvyA JvIjLPIfG3hmccca7HixIohJt0sAaLdmfqJo+iXrg7c8ZLKyWXL4s0BupfxY DkUrnMFoYVIJVb+kHmc7HGWX8nyejTLq4IqvpTiDmKIopZz3iPtd5WnYW.AI I5QCPyhLWBic8faeevEUplQ2yX7soSMMWzS5pD44LRiRpcl5kUjZY3PMT41d NUSBNxLBk7oYjuWSaKSHzV2I0fSuXOmvwKXjgNY4jm057SQR+Bl41OBzRTwd fw+.fYXAA6grnXCrB7cmcbjM.rz1NrBBlCLybCySINi9NiAt0HvF7DDDWuqn qfngDnbGSncRqwD5Gi03BbVf44esniCss4zCNpYQmnvej2O0VfStlVlTt3mH RbN48XH3Non.vfomURxODRvFj8DlUoSVKgmWhUD8uRmdFdrhTpnBtNW90fMa uoGYX4C+9mGL2s+XGgFOnUlXad5f5VTPcv5nFd1F2WPyaPaMoKY3EP5RLkO5 6dmMrnV+.SBrjq9916ZUcqacaoZl2mmfGsXlGxn7D6hq+rl1NJi0rrYFAmwq 70iLZAD540i47Pqe4MrE6ZJ4WWzp93KiboqVPREeEN8Acz712cmKusubX3Ez 6MJQCKKBZVhaj90UwZnkDYHHpNYhOpUDFNdH7dpxMn8RfF9r8yohn3fSJ9JJ zRmjYmW5TfUR5ZHzjfUBnHHoUZo6975teDd0+SLDFdR7Rewvq3vtNtv3xqbl 61hSBAbSlNskgZfGbSpfIjEhrcOqvM3L7JE3cTplyluwoiCY8OExhhrWBBS9 Bj01E6AY9veK1NNF66i6RQkLsAAaN+H79.kYNzDGaN3zt8AsWmVRyxH7cK7k QKMmDLq8pt8VNn9nmfymd75gdhOe5wNTnNzionwYRO1gpK8jb1jiI2V2gOdm O832C87AQ+cpmf9HG+AJm5bQ3Uqz+ErxM9zpDcR96ERysQWXukxqu05QGI4I ZS+uZpwauM8+NonpbB -----------end_max5_patcher-----------
don’t bother – i solved this for the time being by grabbing the signal before loading it on the gpu and then recreating the whole slabchain in cpu-land. not pretty but since i can work with a tiny, tiny matrix it does not affect performance…
some last remark on this if someone else should stumble across this problem: i did not try this in any way but i am just browsing through the filters of jit.gl.imageunit ( https://developer.apple.com/library/mac/#documentation/GraphicsImaging/Reference/CoreImageFilterReference/Reference/reference.html ) and there are a bunch of filters which return culminated values as single pixels which could probably be helpful with this sort of stuff… to get a value (not a pixel) you would still need to readback though.
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