   How would you mathematically rotate a polygon on non-Cartesian graph?
  ok so i'm making a game and i'm working on how i want the collision detection to work. my idea is to use a bounding box that rotates just as a GL_Quad would and check to see if there is an intersection of the segments that make up the squares. so i looked up how to rotate the points of a polygon. i got the following formulasx2 = cos(theta)x1-sin(theta)y1y2 = sin(theta)x1-sin(theta)y1well ok grate but this only works on a Cartesian graph, but the graph that my game works off of is really different. first of all y gains value going down not up, and theta gains value in the opposite direction it normally dose, also 0 degrees is north not east, 90 is east not north, 180 is south not west, 270 is west not south. i have worked out how to get sprites to face particular coordinates but this one perplexes me me quite a bit more. any help on the matter would be appreciated, thanks.   
  You exchange y with -y and/or muddle with angle 'meanings'? 'Non-Cartestian' means something entirely different from what I suspect you think, see also polar and/or cylindrical coordinate systems. Each has their uses, impractical/esoteric as they may sometimes seem.Also, is there a reason why your graph has to be different from what you describe as convention? If it causes difficulties like this for you, perhaps you should reconsider your design slightly.   ;  yes i know the difference between "rectangular" and "Poler" coordinates, i guess i mean non-stranded (i guess non-Cartesian could be some really theoretical math or something like non-euclidean geometry), a stranded Graph y value gains the further "North" or up you go and when talking about Poler coordinates, angles gain value Counter-ClockWise, the X-axis is where 0 and 180 lie and the Y-axis is where 90 and 270 lie. on mine y gains value going down not up, and 0 and 180 lie on the Y-axis not the X-axis, 270 and 90 lie on the X-axis not the Y-axis, and lastly angles gain value going ClockWise not Counter-ClockWise. and no i can only where the origin of this F'ed graph lies, i cant change how SDL and OpenGL handle coordinatess and i cant change how OpenGL rotates stuff   ;  i feel dumb, i tested the rotation formulas and they work on both types of graphs apparently.   ;In this article taken from Game Developer magazine's September 2010 issue, Google game developer advocate Chris Pruett describes how he quickly and cheaply implemented useful metrics into his Android game, Replica Island.  View the full article