[Tutor] move forward in arbitrary direction
Hello, I have what should be a basic math question, but I keep messing it up. How do I code an equation so that when I have an object facing an arbitrary vector, pressing a key will make it move forwards in that direction? (I understand all the key-based setup, it's just the equation for moving in the arbitrary vector direction that's got me stuck) right now i can make something move up and down, or left and right, but if I want to rotate a triangle, then move it so that the 'tip' always points in the direction it's going to move, I get stuck. the thing I have which doesn't work is something like _ vector = [0 0 0] def specialKey(key,x,y): if key == 'up': vector[0] = vector[0] + 1 ___ which I assume should be more like vector = [0 0 0] def specialKey(key,x,y): if key == 'up': vector[0] = vector[0] * math.cos(something???)+ 1 vector[2] = vector[2] * math.sin(something??)+1 -- Any help would be greatly appreciated! ty, Mike ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] move forward in arbitrary direction
The something you're stuck on is the angle the triangle has rotated, measured in radians. If the concept of radians is not familiar, then here's a quick review: There are 2*pi radians in a complete circle (about 6.28) There are 360 degrees in a complete circle 1 radian is approximately 57 degrees Going by radians, 0.0*pi is pointing to the right, 0.5*pi is pointing down, 1.0*pi is pointing to the left, and 1.5*pi is pointing straight up. Keep in mind that python has a math function radians(x), which converts x degrees to radians. If you use that, you can use degrees instead and convert on the fly. (i.e. something to the effect of: math.cos(math.radians(degrees)) would give you the change in vector[0]). If you would rather use radians, keep in mind that the python math module also has the pi constant, which is pretty self explanatory... Hope that helps you... Jonathon Michael Shulman wrote: Hello, I have what should be a basic math question, but I keep messing it up. How do I code an equation so that when I have an object facing an arbitrary vector, pressing a key will make it move forwards in that direction? (I understand all the key-based setup, it's just the equation for moving in the arbitrary vector direction that's got me stuck) right now i can make something move up and down, or left and right, but if I want to rotate a triangle, then move it so that the 'tip' always points in the direction it's going to move, I get stuck. the thing I have which doesn't work is something like _ vector = [0 0 0] def specialKey(key,x,y): if key == 'up': vector[0] = vector[0] + 1 ___ which I assume should be more like vector = [0 0 0] def specialKey(key,x,y): if key == 'up': vector[0] = vector[0] * math.cos(something???)+ 1 vector[2] = vector[2] * math.sin(something??)+1 -- Any help would be greatly appreciated! ty, Mike ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] move forward in arbitrary direction
right now i can make something move up and down, or left and right, but if I want to rotate a triangle, then move it so that the 'tip' always points in the direction it's going to move, I get stuck. http://freespace.virgin.net/hugo.elias/routines/rotate.htm Alan ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] move forward in arbitrary direction
Going by radians, 0.0*pi is pointing to the right, 0.5*pi is pointingdown, 1.0*pi is pointing to the left, and 1.5*pi is pointing straight up.uh, wouldn't pi/2 be pointing up?Don't you set 0 radians to be the positive-x axis and then go counter-clockwise?Or does it not matter? It seems like it would.Thanks,-Luke ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] move forward in arbitrary direction
Hrmmm...I do believe you are right, Luke. My bad...it's been a bit since I actually used this stuff (about 12 years ago in college...heh). And yes, it would matter, unless you swapped the key functionality around...but let's keep it simple, yes? Good thing I'm not programming this project...haha. Doh? Jonathon Luke Paireepinart wrote: Going by radians, 0.0*pi is pointing to the right, 0.5*pi is pointing down, 1.0*pi is pointing to the left, and 1.5*pi is pointing straight up. uh, wouldn't pi/2 be pointing up? Don't you set 0 radians to be the positive-x axis and then go counter-clockwise? Or does it not matter? It seems like it would. Thanks, -Luke ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
