Computer Science Canada Angles? |
| Author: | gg900 [ Tue Apr 01, 2008 11:45 am ] |
| Post subject: | Angles? |
how would i make a bullet or something travel at an angle? or like a line be draw at an angle, how can i change it later? or make a line segment travel in a line. |
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| Author: | Tony [ Tue Apr 01, 2008 12:24 pm ] |
| Post subject: | RE:Angles? |
do you know how to draw a line at a 90 degree angle? That is, vertically straight. |
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| Author: | A.J [ Tue Apr 01, 2008 5:53 pm ] |
| Post subject: | Re: Angles? |
in the equation of a line y= mx + b where m = the slope, the tan of the angle formed by that line and the x-axis is equal to the slope of that line! for example, in the line y = x, the slope = 1 so the angle formed with the x-axis is arctan(1) = 45 degrees. if you want to calculate the angle formed by the bottom-left of the screen and a point P(x,y), its just arctan(y/x) (same as the slope:rise over run) this can be a little confusing if you haven't learned trigonometric functions yet. sry but I'm in a hurry, A.J |
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| Author: | gg900 [ Thu Apr 03, 2008 6:45 pm ] |
| Post subject: | RE:Angles? |
alright, i half get it I can do slope, but i dont know how I would increase the x and y every step. I havent learned trig yet either thanks. |
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| Author: | OneOffDriveByPoster [ Thu Apr 03, 2008 9:05 pm ] |
| Post subject: | Re: Angles? |
I swear there are many posts about this already. In any case, no slope and no trig is required. Point p Point q Parametric form of the line between p and q: r(s) = p + s(q - p) If you want to move in a straight line from point p to point q, then draw your object at r(s) for some values of s from 0 to 1 (inclusive). If the equation is confusing, then consider the midpoint between p and q--it is r(0.5). If you have p, some distance to travel (length) and an angle (theta) instead, then q = p + length*( cos(theta), sin(theta) ). Okay, so there was trig... |
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| Author: | andrew. [ Fri Apr 04, 2008 9:04 pm ] |
| Post subject: | Re: RE:Angles? |
gg900 @ Thu Apr 03, 2008 6:45 pm wrote: I havent learned trig yet either thanks.
That's the problem. Do a quick Google search. Trig is easy and doesn't take a while to learn. I learned it in 5 minutes. Once you learn that, all your angle problems are solved. |
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