How to use 2D logical mask on an image without for loop?

I have two image matrices A and B with size 512 x 512 x 3, and a logical mask of size 512 x 512. For each position with true value in the mask, I want to set A's value to B's. Currently I only know the for loop solution:

for y = 1 : height
    for x = 1 : width
        if mask(y,x)
            A(y,x,:) = B(y,x,:)
        end
    end
end

Is there a way to avoid the for loop?

Answer 1

[KSSV]

B = zeros(512,512,3) ; 
for i = 1:3
    T1 = B(:,:,1) ; 
    T2 = A(:,:,i) ; 
    T1(idx) = T2(idx) ; 
    B(:,:,i) = T1 ; 
end

[xiaojuezi]

Does this solution set B's value as A's instead of other way round as in the for loop?

[KSSV]

It sets A's values to B. You can change it, if you want the other way.