使用OpenGL繪制圓環體(Torus)

本篇介紹一下使用OpenGL繪制圓環體的方法。程序是在C#和OpenTK環境下編譯的。

代碼：

/// <summary>
/// 繪制圓環體
/// </summary>
/// <param name="Radius">圓環體半徑</param>
/// <param name="TubeRadius">圓環體段半徑</param>
/// <param name="Sides">圓環體段的側面數</param>
/// <param name="Rings">圓環體段數</param>
void DrawTorus(double Radius = 50, double TubeRadius= 10, int Sides = 20, int Rings = 30)
{
    double sideDelta = 2.0 * Math.PI / Sides;
    double ringDelta = 2.0 * Math.PI / Rings;
    double theta = 0;
    double cosTheta = 1.0;
    double sinTheta = 0.0;

    double phi, sinPhi, cosPhi;
    double dist;

    GL.Color3(1.00f, 0.0f, 0.0f);

    for (int i = 0; i < Rings; i++)
    {
        double theta1 = theta + ringDelta;
        double cosTheta1 = Math.Cos(theta1);
        double sinTheta1 = Math.Sin(theta1);
        
        GL.Begin(BeginMode.QuadStrip);
        phi = 0;
        for (int j = 0; j <= Sides; j++)
        {
            phi = phi + sideDelta;
            cosPhi = Math.Cos(phi);
            sinPhi = Math.Sin(phi);
            dist = Radius + (TubeRadius * cosPhi);

            GL.Normal3(cosTheta * cosPhi, sinTheta * cosPhi, sinPhi);
            GL.Vertex3(cosTheta * dist, sinTheta * dist, TubeRadius * sinPhi);

            GL.Normal3(cosTheta1 * cosPhi, sinTheta1 * cosPhi, sinPhi);
            GL.Vertex3(cosTheta1 * dist, sinTheta1 * dist, TubeRadius * sinPhi);
        }
        GL.End();
        theta = theta1;
        cosTheta = cosTheta1;
        sinTheta = sinTheta1;

    }


}