TheGameCreators - CodeBase - Interactive Bezier Curve

Category: Math / Physics

Version: 1.0

Information

Uploaded: 20th Oct 2003 13:21

Modified: 1st Jan 1970 01:00

Author: Richard Davey

Summary

This program creates a real-time bezier curve of which you can control all 4 points (start, end, control 1 and control 2) by pressing the keys shown and moving the mouse. Bezier curves are extremely useful for spirte paths and 3D object trajectories.

Full Description

DarkBASIC Professional Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

Rem Project: Bezier Curve

Rem Created: 08/10/2003 02:15:43

Rem ***** Main Source File *****

sync rate 0

sync on

sw = screen width()

sh = screen height() - 80

randomize timer()

x1 = rnd(sw)

y1 = rnd(sh) + 16

x2 = rnd(sw)

y2 = rnd(sh) + 16

c1x = rnd(sw)

c1y = rnd(sh) + 16

c2x = rnd(sw)

c2y = rnd(sh) + 16

mousemode = 0

control = 0

set text font "Arial"

set text size 16

repeat

cls

if inkey$()="a"

mousemode = 1

control = 1

endif

if inkey$()="b"

mousemode = 1

control = 2

endif

if inkey$()="1"

mousemode = 1

control = 3

endif

if inkey$()="2"

mousemode = 1

control = 4

endif

if mouseclick()=1

mousemode = 0

endif

if mousemode = 1

select control

case 1

x1 = mousex()

y1 = mousey()

endcase

case 2

x2 = mousex()

y2 = mousey()

endcase

case 3

c1x = mousex()

c1y = mousey()

endcase

case 4

c2x = mousex()

c2y = mousey()

endcase

endselect

endif

text 0,0,"A: " + str$(x1) + "x " + str$(y1) + "y"

text 0,20,"B: " + str$(x2) + "x " + str$(y2) + "y"

text 0,40,"C1: " + str$(c1x) + "x " + str$(c1y) + "y"

text 0,60,"C2: " + str$(c2x) + "x " + str$(c2y) + "y"

center text screen width()/2,screen height()-20,"Bezier Curve - Press A/B/1/2 to move the points. Left Mouse to set"

Bezier(x1, y1, x2, y2, c1x, c1y, c2x, c2y)

sync

until escapekey()

end

function Bezier(x1, y1, x2, y2, c1x, c1y, c2x, c2y)

x as float

y as float

cx as float

bx as float

ax as float

cy as float

by as float

ay as float

x = x1

y = y1

cx = 3 * (c1x - x1)

bx = 3 * (c2x - c1x) - cx

ax = x2 - x1 - cx - bx

cy = 3 * (c1y - y1)

by = 3 * (c2y - c1y) - cy

ay = y2 - y1 - cy - by

text x1,y1,"a"

text x2,y2,"b"

text c1x,c1y,"c1"

text c2x,c2y,"c2"

for t# = 0 to 1.05 step .05

x = ((ax * t# + bx) * t# + cx) * t# + x1

y = ((ay * t# + by) * t# + cy) * t# + y1

`  First time through?

if t# = 0

oldx = x

oldy = y

endif

line oldx, oldy, x, y

oldx = x

oldy = y

next t#

endfunction

Download

Please login to download

Comments

No comments yet.

Author Name:	Richard Davey
CodeBase Entries:	57

CodeBase - Interactive Bezier Curve

Information

Summary

Full Description

DarkBASIC Professional Source Code

Download

Screen Shot

Author

Comments