| Hi All, " i'm not expert programmer, just a biologist student :-/ with self-teached python experience so apologize my questions if they are based on wrong assumptions " for my study i need to write a code to inteface a joystick device with an open source application similar to google earth. this application is a 3d globe based on openscenegraphic (OSG), it has a "tcp listner interface" that accept xml message to move a camera-view around the globe the message to move the globe is something like : go_to_lat_lon(latitude longitude roll picth head) i tried to code in python using pygame, the results is (my fault) an "ugly" code that is not able to update the position according with heading changes (view direction). exactly i have a 3 axis joystick axis_x -> +/- longitude axis_y -> +/- latitude axis_z -> +/- 0-360° (heading) axis_v = 0-1 (speed) the code i wrote use the axis_x and axis_y to change longitude and latitude and axis_z to change the view direction. but it is totally wrong beacouse if i have heading = 0 = 360 (e.g. look to north) the code works as aspected ... but if i change direction (view turns) the axis code is not update. so if i look yo east and put the joysrick up (go ahead) it don't go to east .. but go ever to north. move the axis_y up move the planet to north move the axis_y down move the planet to south move axis_y left and right move the planet to west and east but beacouse my code is totally separated by the heading changes, if i change heading the joystik x/y axis action is immutate. this beacouse i connect the x/y action to a code that simply do an increase/decrease lon-lat values. increase : for i in arange(j , j+1): lati = [sum(zlat)] a = abs(axis_v) * abs(axis_x) lati.insert( i+1,a ) zlat = array(lati) lat = sum(zlat) j = 0.1 for i in arange(j , j+1): lati = [sum(zlat)] a = abs(axis_v) * abs(axis_x) lati = [sum(lati) - a] zlat = array(lati) lat = sum(zlat) j = 0.1 i used the increase decrease code to handle all the avaiable condition, North, South, East, Ovest, Ne, Nw , Se , Sw : 1) axis_x < 0 axis_y == 0 2) axis_x == 0 axis_y > 0 3) axis_x > 0 axis_y == 0 4) axis_x == 0 axis_y < 0 5) axis_x < 0 axis_y > 0 6) axis_x > 0 axis_y > 0 7) axis_x > 0 axis_y < 0 8) axis_x < 0 axis_y < 0 i hope exists already a function in opengl that can help me to solve this problem reading a lot on google seems my problem can be solved using complex math like quaternion or rotation around an arbitrary axis. i can ignore roll and pich, beacouse i can chenge them using the joystick hat .. an roll and pich are ininfluent on the lon-lat position ... while the heading is strictly related to the position beacouse it represent the movment direction. plese apologize again my ugly code, this what i'm actually using : this the results : while here i tried to learn quaternion .. but my brain is not hable "yet" to undstand how to works with quaternion in a "longitude - latitude" space :-( i hope some one can help me! please i'm italian so it is a bit hard to find the right word to describe my problem for eny more detailed explanaton, please ask me where i need to give more precise informations. thanks to help me! ciao, Massimo. |