Moving an entity in a wavy pattern

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Socoder -> Blitz -> Moving an entity in a wavy pattern
Mon, 07 Jul 2008, 18:56
Orion Pax	I need to make some entities in blitz move but in a wavy pattern. I need it to go straight but sway left and right. Right now I am just counting in a loop and reversing the turning direction after so many loops. I am sure there is a better way but I dont know.
Mon, 07 Jul 2008, 19:06
Scherererer	use a sin wave!
Mon, 07 Jul 2008, 19:27
Orion Pax	I figured that was it but I have no idea how to do a sin wave. I guess I do a sin on my entities yaw value?
Mon, 07 Jul 2008, 19:44
Scherererer	Graphics 854, 480 Local t# = 0 While Not KeyDown(1) Cls t# = t# + 5 If (t# > 360) Then t# = 5 Rect GraphicsWidth()/2 + (150.0Sin#(t#)), GraphicsHeight()/2-10, 20, 20 Delay 25 VWait : Flip False Wend --v here's a simple pendulum-type-motion as an example if you get stuck \|edit\| Yeah you could set the yaw value to the output of the sin function. notice in my example i multiplied the sin value by 150: that's because it only goes from 0.0000-1.0000, so if you want a more intense change, you have to add a larger multiplier. so, if you want to move in a variance of 15 degrees, you'd set it to 15Sin(theta#) \|edit\| -=-=- YouTube Twitter Computer Science Series: Logic (pt1) (part 2) (part 3) 2's Complement Mathematics: Basic Differential Calculus
Mon, 07 Jul 2008, 20:07
Orion Pax	y=y+5 If y>360 Then y=5 MoveEntity sphere,0,0,3 TranslateEntity sphere,Sin(y),0,0 --v Ok I do this but it goes back and forth much to the right. And none to the left.
Mon, 07 Jul 2008, 23:04
Scherererer	aha! i didn't figure it out until i remembered calculus: in your scenario, you have the sine curve acting as the velocity graph, in mine its the position graph. What that means is, that your object's velocity is going from 1 to -1, whereas my position is going from -1 to 1. Therefore, your object's position is the integral of the sin function, being a cosine function. Now, the function with the integral that is a sine graph, is, of course, cosine. long story short, change Sin to Cos y=y+5 If y>360 Then y=5 MoveEntity sphere,0,0,3 TranslateEntity sphere,Cos(y),0,0 --v -=-=- YouTube Twitter Computer Science Series: Logic (pt1) (part 2) (part 3) 2's Complement Mathematics: Basic Differential Calculus