While making a little Pong game in C++ OpenGL, I decided it'd be fun to create arcs (semi-circles) when stuff bounces. I decided to skip Bezier curves for the moment and just go with straight algebra, but I didn't get far. My algebra follows a simple quadratic function (y = +- sqrt(mx+c)). This little excerpt is just an example I've yet to fully parameterize, I just wanted to see how it would look. When I draw this, however, it gives me a straight vertical line where the line's tangent line approaches -1.0 / 1.0. Is this a limitation of the GL_LINE_STRIP style or is there an easier way to draw semi-circles / arcs? Or did I just completely miss something obvious? void Ball::drawBounce() { float piecesToDraw = 100.0f; float arcWidth = 10.0f; float arcAngle = 4.0f; glBegin(GL_LINE_STRIP); for (float i = 0.0f; i < piecesToDraw; i += 1.0f) // Positive Half { float currentX = (i / piecesToDraw) * arcWidth; glVertex2f(currentX, sqrtf((-currentX * arcAngle)+ arcWidth)); } for (float j = piecesToDraw; j > 0.0f; j -= 1.0f) // Negative half (go backwards in X direction now) { float currentX = (j / piecesToDraw) * arcWidth; glVertex2f(currentX, -sqrtf((-currentX * arcAngle) + arcWidth)); } glEnd(); } Thanks in advance.