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Points parallel to Bezier Curve

I am developing an application that uses OpenGL and I need to create a series of parallel QUAD_STRIPS. You can think of it as a curved road with multiple lanes and I need to draw each lane separately. These lanes need to follow a set Bezier curve (with 2 control points) that is located along the center stripe of the road.

I can calculate the points along this cubic Bezier curve, but I am looking for a way to calculate a like number of points along both edges of each lane that parallels the center stripe that have a consistent offset or lane width if you will. If it matters, the initial curve can have any orientation in the Cartesian plane.

ozo

A curve that's a fixed distance from a Bezier curve is not in general something as simple as another Bezier curve.
You might try just adding a perpendicular to the tangent, or try the methods here:
http://www.cis.usouthal.edu/~hain/general/Publications/Bezier/BezierFlattening.pdf

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aburr

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swestbrook60

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Since they are similar answers I will split the points. These solutions gave me another idea too. That is to find the angle of each segment in the original cure, then offset a point the width of the lane at the segment midpoint. With staggered points I can use a GL_TRIANGLE_STRIP instead. I can always adjust the number of segments in the original curve to maintain a smooth result. Since no dramatic curves are expected this should give a fairly good rendering. I will try it and see how it works under various conditions.

Member_2_5069294

Thanks for the points. I've actually written some code for doing just what you are doing, you have the right idea. The code I wrote was for a GPS device, to show road maps.