private void drawRoundCorner(Vector3 center, float radius, float angle, AGSBoundingBox border, FourCorners <IGLColor> colors)
{
Vector2 tex = new Vector2();
GLVertex centerVertex = new GLVertex(center.Xy, tex, getColor(colors, border, center));
_roundCorner[0] = centerVertex;
float step = (90f / (_roundCorner.Length - 2));
for (int i = 1; i < _roundCorner.Length; i++)
{
float anglerad = (float)Math.PI * angle / 180.0f;
float x = (float)Math.Sin(anglerad) * radius;
float y = (float)Math.Cos(anglerad) * radius;
angle += step;
Vector3 point = new Vector3(x + center.X, y + center.Y, 0f);
_roundCorner[i] = new GLVertex(point.Xy, tex, getColor(colors, border, point));
}
_glUtils.DrawTriangleFan(0, _roundCorner);
}
