Rotating Rectangle

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Socoder -> Blitz -> Rotating Rectangle
Tue, 09 Jan 2007, 05:02
mike_g	I'm trying to write a function that draws a rectangle at any angle. Heres the code I have so far: SetBuffer BackBuffer() While Not KeyHit(1) Cls ROTATING_RECT(200, 150, 80, 30, i) i=i+1 If i = 360 Then i = 0 Flip Wend Function ROTATING_RECT(x, y, w, h, angle#) s = Sin(angle) c = Cos(angle) sw = ws cw = wc sh = hs ch = hc Plot x, y Plot x+cw, y+sw Plot x+cw-sh, y+sw+ch Plot x-sh, y+ch End Function --v The first problem I have with this is that the rectangle rotates in 45 degree increments when I would like to be able to rotate it by any increment. Another problem is that the rectangle seems bigger than normal when drawn at a 45 degree angle. Also I would like it to rotate from the center of the shape instead of the corner. Can someone good at maths help me? Cheers.
Tue, 09 Jan 2007, 05:20
JL235	Your missing out the '#'s from your variables (at least: 's', 'c' and 'angle'), making them integers rather then floats. That is why it is not rotating correctly.
Tue, 09 Jan 2007, 05:32
mike_g	0_0 so I am. silly mistake. I should be able to code it to rotate from the centre myslef. Thanks.
Thu, 11 Jan 2007, 14:56
mike_g	I am still having problems... I have been trying to change the point of rotation from a corner of the shape to the centre of it. I seem to have got it centred on one axis but cant centered on the other, and my rectangle now seems to be bigger than its meant to be o_0. Anyway I'm not so good at maths so I have sort of been guessing what to do, heres my code: SetBuffer BackBuffer() While Not KeyHit(1) Cls ROTATING_RECT(200, 150, 80, 40, i) i=i+1 If i = 360 Then i = 0 Flip Wend Function ROTATING_RECT(x, y, w, h, angle) s# = Sin(angle) c# = Cos(angle) ox = (w/2) oy = (h/2) sw# = oxs cw# = oxc sh# = oys ch# = oyc x1 = x-cw-ch: y1 = y-sw-sh x2 = x+cw+ch: y2 = y+sw+sh x3 = x+cw-sh+ch-sw: y3 = y+sw+ch+sh+cw x4 = x-sh-cw-sw-ch: y4 = y+ch-sw+cw-sh Plot x, y Plot x1, y1 Plot x2, y2 Plot x3, y3 Plot x4, y4 End Function --v Since my code might be more confusing than helpfull. Heres the original rotating rectangle code with a little test prog: SetBuffer BackBuffer() While Not KeyHit(1) Cls ROTATING_RECT(200, 150, 80, 30, i) i=i+1 If i = 360 Then i = 0 Flip Wend Function ROTATING_RECT(x, y, w, h, angle) s# = Sin(angle) c# = Cos(angle) sw# = ws cw# = wc sh# = hs ch# = hc Plot x, y Plot x+cw, y+sw Plot x+cw-sh, y+sw+ch Plot x-sh, y+ch End Function --v Help with this would be much appreciated
Thu, 11 Jan 2007, 16:13
JL235	Here, I also included a 'rotatingPolygon' function, which will create a shape with multiple sides. However the corners are calculated from the centre of the shape, so it can make squares but not rectangles. I made that ages ago in Ruby. SetBuffer BackBuffer() While Not KeyHit(1) Cls rotatingRectangle(200, 150, 80, 30, i) rotatingPolygon(200, 150, 230, 130, 18, i) i=i+1 If i = 360 Then i = 0 Flip Wend End Function rotatingPolygon(x, y, width, height, noSides, angle) width = width/2 height = height/2 For sideNo = 0 To noSides x1# = widthCos( (sideNo/Float(noSides))360.0) y1# = heightSin( (sideNo/Float(noSides))360.0) c# = Cos((angle+180)) s# = Sin((angle)) x2# = x1# x1# = x1#c# + y1#-s# y1# = x2#s# + y1#c# Plot x1#+x,y1#+y Next End Function Function rotatingRectangle(x, y, width, height, angle) width = width/2 height = height/2 c# = Cos((angle+180)) s# = Sin((angle)) For i = 1 To 4 Select i Case 1 x1 = width y1 = height Case 2 x1 = -width y1 = height Case 3 x1 = width y1 = -height Case 4 x1 = -width y1 = -height End Select x1copy = x1 x1 = x1c# + y1-s# y1 = x1copys# + y1c# Plot x+x1, y+y1 Next End Function --v I should also credit Noel Cower for his help in getting this to work.
Thu, 11 Jan 2007, 16:20
mike_g	Thanks diablo, trying to work that out was starting to do my head in. Now I have just got to put it to use