Spline Editor

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mike_g	Created : 07 July 2008 Edited : 07 July 2008 Language : Blitz Spline Editor Edit Paths Made Of Bezier Curves
I had a play around with Jay's bezier curve code and came up with the start of a simple spline editor. At the moment it only works with quadratic bezier curves, but if I find the time i plan to add cubic curves, save/load co-ords to/from files and allow users to add points. It might be useful then. Anyway heres the code: ;****************************************************************; ;----------------------- DATA TYPES REQUIRED ----------------------; ;**************************************************************; Const MAX_SPLINE_SIZE = 100 Const CURVE_DETAIL = 500 Type point Field x, y End Type Type spline Field size Field pts.point[MAX_SPLINE_SIZE] End Type ;Temp array for holding points used in spline constructor Dim temp.point(MAX_SPLINE_SIZE) ;**************************************************************; ;------------------------- FUNCTIONS USED -------------------------; ;***************************************************************; Function NewPoint.point(x, y) Local p.point = New point p\x = x p\y = y Return p End Function Function NewSpline.spline() Local s.spline = New spline Local i = 0 While(temp.point(i) <> Null) s\pts.point[i] = temp.points(i) i = i + 1 If(i = MAX_SPLINE_SIZE) Then Exit Wend s\size = i Return s End Function Function DrawSpline(s.spline) i=0 While(s\pts.point[i+2] <> Null) BezierCurve(s\pts.point[i], s\pts.point[i+1], s\pts.point[i+2]) i=i+2 Wend End Function Function BezierCurve(p1.point, p2.point, p3.point) For i = 0 To CURVE_DETAIL x1 = QuadraticBezier(i-1,p1\x,p2\x,p3\x) y1 = QuadraticBezier(i-1,p1\y,p2\y,p3\y) x2 = QuadraticBezier(i,p1\x,p2\x,p3\x) y2 = QuadraticBezier(i,p1\y,p2\y,p3\y) Line x1, y1, x2, y2 Next End Function Function QuadraticBezier(Perc#,p1#,p2#,p3#) d1#=(((p2-p1)perc)/CURVE_DETAIL)+p1 d2#=(((p3-p2)perc)/CURVE_DETAIL)+p2 d3#=(((d2-d1)perc)/CURVE_DETAIL)+d1 Return d3 End Function Function CubicBezier(perc#,p1#,p2#,p3#,p4#) d1#=(((p2-p1)perc)/CURVE_DETAIL)+p1 d2#=(((p3-p2)perc)/CURVE_DETAIL)+p2 d3#=(((p4-p3)perc)/CURVE_DETAIL)+p3 d4#=QuadraticBezier(perc,d1,d2,d3) Return d4 End Function ;***************************************************************; ;--------------------------- TEST PROGRAM -------------------------; ;**************************************************************; Graphics 800,600,32,2 SetBuffer BackBuffer() temp.point(0) = NewPoint(200, 200) temp.point(1) = NewPoint(350, 350) temp.point(2) = NewPoint(600, 200) temp.point(3) = NewPoint(800, 300) temp.point(4) = NewPoint(600, 500) temp.point(5) = NewPoint(300, 400) temp.point(6) = NewPoint(200, 450) s.spline = NewSpline() Global hold = -1 ;indicates which point is held While Not KeyHit(1) Cls DrawPoints(s) Color 255, 255, 255 DrawSpline(s) MouseInput(s) Flip Delay(3) Wend ;**************************************************************; ;--------------------- TEST PROGRAM FUNCTIONS ---------------------; ;***************************************************************; Function GetDistance(x1, y1, x2, y2) Local dx = x1-x2 Local dy = y1-y2 Local distance# = Sqr((dxdx)+(dy*dy)) Return distance# End Function Function DrawPoints(s.spline) Local i=0, prox# ;move a point thats being held If(hold <> -1) s\pts.point[hold]\x = MouseX() s\pts.point[hold]\y = MouseY() EndIf While(s\pts.point[i] <> Null) prox# = GetDistance(MouseX(), MouseY(), s\pts.points[i]\x, s\pts.points[i]\y) If(prox# < 5) hilight = 1 Else hilight = 0 EndIf If(i And 1) Color 150, 0, 0 Else Color 0, 0, 150 EndIf Oval s\pts.points[i]\x-4, s\pts.points[i]\y-4, 9, 9, hilight If(s\pts.point[i+1] <> Null) Color 0, 0, 30 Line s\pts.points[i]\x, s\pts.points[i]\y, s\pts.points[i+1]\x, s\pts.points[i+1]\y EndIf i=i+1 Wend End Function Function MouseInput(s.spline) If MouseHit(1) If(hold = -1) ;pick up point GrabPoint(s) Else hold = -1 ; drop point EndIf EndIf End Function Function GrabPoint(s.spline) Local i = 0 While(s\pts.point[i] <> Null) prox# = GetDistance(MouseX(), MouseY(), s\pts.points[i]\x, s\pts.points[i]\y) If(prox# < 5) hold = i Return True EndIf i = i+1 Wend Return False End Function --v Click on the points to drag them around

Comments
Monday, 07 July 2008, 14:51
Jayenkai	Looks good enough to me! So much maths, lately, my head's about to pop!
Wednesday, 09 July 2008, 16:26
mike_g	Cheers Jay. I decided to convert it to Java for the editor. However I plan to add code to load the files produced in Blitz and C. Heres a screenie:
Wednesday, 09 July 2008, 16:27
Jayenkai	Nice!!
Wednesday, 09 July 2008, 23:58
shroom_monk	Wow! That looks pretty awesome!
Thursday, 10 July 2008, 12:21
mike_g	Hey, I'm glad you like it shroom Heres an effect I knocked up using a spline made in my editor: ;****************************************************************; ;----------------------- DATA TYPES REQUIRED ----------------------; ;**************************************************************; Const MAX_SPLINE_SIZE = 1000 Const CURVE_DETAIL = 50 Type point Field x, y End Type Type spline Field size Field pts.point[MAX_SPLINE_SIZE] End Type ;Temp array for holding points used in spline constructor Dim temp.point(MAX_SPLINE_SIZE) Const RUNNER_SIZE = 12 Type runner Field x, y Field s.spline Field pos[RUNNER_SIZE] Field loc End Type ;**************************************************************; ;------------------------- FUNCTIONS USED -------------------------; ;***************************************************************; Function NewPoint.point(x, y) Local p.point = New point p\x = x p\y = y Return p End Function Function NewSpline.spline() Local s.spline = New spline Local i = 0 While(temp.point(i) <> Null) s\pts.point[i] = temp.points(i) i = i + 1 If(i = MAX_SPLINE_SIZE) Then Exit Wend s\size = i Return s End Function Function DrawSpline(s.spline) i=0 While(s\pts.point[i+2] <> Null) BezierCurve(s\pts.point[i], s\pts.point[i+1], s\pts.point[i+2]) i=i+2 Wend End Function Function BezierCurve(p1.point, p2.point, p3.point) For i = 0 To CURVE_DETAIL ptx1 = p1\x+scroll_x: pty1 = p1\y+scroll_y ptx2 = p2\x+scroll_x: pty2 = p2\y+scroll_y ptx3 = p3\x+scroll_x: pty3 = p3\y+scroll_y x1 = QuadraticBezier(i-1, ptx1, ptx2, ptx3) y1 = QuadraticBezier(i-1, pty1, pty2, pty3) x2 = QuadraticBezier(i , ptx1, ptx2, ptx3) y2 = QuadraticBezier(i , pty1, pty2, pty3) Line x1, y1, x2, y2 Next End Function Function QuadraticBezier(Perc#,p1#,p2#,p3#) d1#=(((p2-p1)perc)/CURVE_DETAIL)+p1 d2#=(((p3-p2)perc)/CURVE_DETAIL)+p2 d3#=(((d2-d1)perc)/CURVE_DETAIL)+d1 Return d3 End Function Function CubicBezier(perc#,p1#,p2#,p3#,p4#) d1#=(((p2-p1)perc)/CURVE_DETAIL)+p1 d2#=(((p3-p2)perc)/CURVE_DETAIL)+p2 d3#=(((p4-p3)perc)/CURVE_DETAIL)+p3 d4#=QuadraticBezier(perc,d1,d2,d3) Return d4 End Function ;***************************************************************; ;--------------------------- TEST PROGRAM -------------------------; ;***************************************************************; Graphics 800,600,32, 1 SetBuffer BackBuffer() SeedRnd MilliSecs() Read size For i=0 To size Read x Read y temp.point(i) = NewPoint(x, y) Next s.spline = NewSpline() For a = 0 To 9 f.runner = CreateRunner(s) f\loc = a4 Next Global hold = -1 ;indicates which point is held Global scroll_x=0, scroll_y=0 While Not KeyHit(1) Runner() Flip Wend ;******************************************************************; ;--------------------------- EXTRA FUNCTIONS ------------------------; ;******************************************************************; Function CreateRunner.runner(s.spline) Local n.runner = New runner n\x = s\pts.points[0]\x n\y = s\pts.points[0]\y n\s = s n\loc = 0 For i = 0 To RUNNER_SIZE n\pos[i]=i Next Return n End Function Function Runner() For r.runner = Each runner DrawRunner(r) RunnerDot(r.runner) Next End Function Function DrawRunner(r.runner) overlap = False For i= 0 To RUNNER_SIZE-1 rd = rd+10 gr = gr+8 bl = bl+5 If overlap = False If r\pos[i] < r\pos[i+1] ptx1 = r\s\pts[r\loc]\x: pty1 = r\s\pts[r\loc]\y ptx2 = r\s\pts[r\loc+1]\x: pty2 = r\s\pts[r\loc+1]\y ptx3 = r\s\pts[r\loc+2]\x: pty3 = r\s\pts[r\loc+2]\y If i < RUNNER_SIZE-1 x1 = QuadraticBezier(r\pos[i], ptx1, ptx2, ptx3) y1 = QuadraticBezier(r\pos[i], pty1, pty2, pty3) x2 = QuadraticBezier(r\pos[i+1] , ptx1, ptx2, ptx3) y2 = QuadraticBezier(r\pos[i+1] , pty1, pty2, pty3) Color rd, gr, bl: Line x1, y1, x2, y2 EndIf Else ; switchover overlap = True If r\loc+4 >= r\s\size ;End of spline r\loc=0 Return EndIf ptx1 = r\s\pts[r\loc]\x: pty1 = r\s\pts[r\loc]\y ptx2 = r\s\pts[r\loc+1]\x: pty2 = r\s\pts[r\loc+1]\y ptx3 = r\s\pts[r\loc+2]\x: pty3 = r\s\pts[r\loc+2]\y x1 = QuadraticBezier(r\pos[i], ptx1, ptx2, ptx3) y1 = QuadraticBezier(r\pos[i], pty1, pty2, pty3) x2 = r\s\pts[r\loc+2]\x y2 = r\s\pts[r\loc+2]\y Color rd, gr, bl: Line x1, y1, x2, y2 EndIf Else If r\loc+4 >= r\s\size ;End of spline r\loc=0 Return EndIf ptx1 = r\s\pts[r\loc+2]\x: pty1 = r\s\pts[r\loc+2]\y ptx2 = r\s\pts[r\loc+3]\x: pty2 = r\s\pts[r\loc+3]\y ptx3 = r\s\pts[r\loc+4]\x: pty3 = r\s\pts[r\loc+4]\y If i < RUNNER_SIZE-1 x1 = QuadraticBezier(r\pos[i], ptx1, ptx2, ptx3) y1 = QuadraticBezier(r\pos[i], pty1, pty2, pty3) x2 = QuadraticBezier(r\pos[i+1] , ptx1, ptx2, ptx3) y2 = QuadraticBezier(r\pos[i+1] , pty1, pty2, pty3) Color rd, gr, bl: Line x1, y1, x2, y2 EndIf EndIf Next For i= 0 To RUNNER_SIZE r\pos[i] = r\pos[i]+1 If r\pos[i] = CURVE_DETAIL Then r\pos[i]=0 Next If r\pos[0] = 0 r\loc=r\loc+2 EndIf End Function Function RunnerDot(r.runner) overlap = False For i=0 To RUNNER_SIZE-1 If r\pos[i] > r\pos[i+1] Then overlap = True Next If overlap = False ptx1 = r\s\pts[r\loc]\x: pty1 = r\s\pts[r\loc]\y ptx2 = r\s\pts[r\loc+1]\x: pty2 = r\s\pts[r\loc+1]\y ptx3 = r\s\pts[r\loc+2]\x: pty3 = r\s\pts[r\loc+2]\y Else If r\loc+4 < r\s\size ptx1 = r\s\pts[r\loc+2]\x: pty1 = r\s\pts[r\loc+2]\y ptx2 = r\s\pts[r\loc+3]\x: pty2 = r\s\pts[r\loc+3]\y ptx3 = r\s\pts[r\loc+4]\x: pty3 = r\s\pts[r\loc+4]\y EndIf x2 = QuadraticBezier(r\pos[RUNNER_SIZE] , ptx1, ptx2, ptx3) y2 = QuadraticBezier(r\pos[RUNNER_SIZE] , pty1, pty2, pty3) Color 255, 0, 0 Oval x2-1, y2-1, 3, 3, 1 End Function Data 52, 100, 180, 10, 120, 60, 90, 40, 120, 100, 180, 60, 120, 80, 90, 70, 120, 100, 180, 130, 120, 120, 90, 140, 120, 100, 180, 160, 120, 140, 90, 190, 120, 100, 180, 20, 140, 30, 180, 37, 209, 70, 210, 30, 190, 60, 180, 80, 180, 100, 190, 120, 180, 150, 180, 180, 190, 130, 210, 170, 210, 180, 180, 189, 151, 100, 180, 110, 260, 90, 290, 20, 420, 50, 480, 130, 330, 190, 350, 218, 359, 160, 410, 110, 450, 220, 370, 244, 352, 170, 320, 142, 308, 50, 480, 20, 430, 50, 340, 59, 311, 20, 270, 60, 270, -21, 226 --v I might have a go at coding a blitz library with different effects that work on splines, but first theres still a lot of work to do on the editor.
Tuesday, 06 April 2010, 09:51
dna	Very Clever. Well Done

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