Angle quadrants
Monkey Forums/Monkey Programming/Angle quadrants
| ||
| Hi all I am wondering what considerations I need to make when utilizing player and enemy angles. Since screen coords are in the fourth quadrant, it is confusing me when thinking about movement in the first quadrant. 2 | 1 ------- 3 | 4 I have a function that takes an angle and returns a vector i.e. For 0 degrees the vector faces right, 90 is down, etc... vector.x = cos(angle) vector.y = sin(angle) Do you guys transform the quadrant? If so how? Or do you just base all your movement in the 4th quadrant? What makes it even more confusing is image rotation in Monkey. I am just hoping to hear your thoughts and solutions. Thanks |
| ||
| ...is this what you mean? Atan2(x,y) 0-90, 90-180, 180-270, 270-360 or Atan2r(x,y) for 0 to 2*PI. |
| ||
| hmmm, I am not sure how to explain When utlizing x = cos(angle) y = sin(angle) an angle of 90 will result in the facing vector facing down (4th quadrant) and angle of 180 will result in the facing vector facing left (3rd quadrant) When using atan2(x,y) on the same vectors above it returns 0 and -90 respectively. I realize I can change the signs of the vectors or swap them to place it in another quadrant i.e. atan2(y,x) will place resulting angles in the same quadrants specified above. I am just not sure what others do to make sure their angles are consistent in their games. I hope I am making sense, I am just struggling to keep consistency throughout my applications. Here is are posts talking about rotating images which yields different results too. http://www.monkeycoder.co.nz/Community/posts.php?topic=4319#46139 http://www.monkeycoder.co.nz/Community/posts.php?topic=356#2614 |
| ||
| -Atan2(y,x) yields clockwise movement as well as vector.x = sin(angle) vector.y = cos(angle) Is this correct? This is just new to me as I normally use cos(angle) for x component and sin(angle) for y component. Even with the above noted, they still exhibit different angles, I am so confused. |
| ||
| i would use a quadrant list and a method IsInside(x,y) left,top x>=x1 and y<=y1 right,bottom x>=x2 and y<=y2 a simulated step move x = cos(angle)+gridwidth y = sin(angle)+gridheight |
| ||
| Part of the confusion here is that monkey's Atan2 function is a bit weird in its variable definition. Just imagine the first parameter is y rather than x, and it's just like any other language. From there on out, do what you like as long as it's consistent. |
| ||
| Thanks for the replies guys, I will make sure all my angles are consistent. |
| ||
| Encapsulate it all in a way that works for you and forget about it. I agree with you that this sort of thing can be a real headscratcher, surprisingly so. |
   |