2 motors controlled by one joystick

RickyG86:
I'm new to this but I want to achieve something similar but a little less complicated, well in my mind it is . I'm usig a single joystick and 2 motors for an underwater ROV project. Along the y axis its pretty straight foward. stick up both motors full speed fwd, stick down both motors full speed rev and everything in between. Lets call the motors M1 and M2. when i'm refering to the speed of the motors I will just say that full fwd speed is +127, 0 is off and full rev is -127. If that should be different let me know, but for now thats burned into my mind. Ok fwd and rev are cake, turning isn't that hard either. if the joystick is all the way left then m1 is -127 and m2 is +127. if the joystick is half left then m1 is -63 and m2 is +63.

Programming this alone doesn't seem that difficult but when i want to turn while moving forward... joystick all the way to the left and up M1 is 0 and m2 is +127

I have no Idea where to start with this but If it cant happen i can just use two sticks.

It is possible to do with one stick and this post has a few solutions on it already. But if your still having trouble, post what you have already and we will see what we can do.