随手小代码——绘制花托(轮胎)

百度文库的一篇文章，介绍了OpenGL超级宝典中经常用到的gltDrawTorus的实现原理，图文并茂，很不错。

原文链接：http://wenku.baidu.com/view/57545ef1fab069dc50220140.html

（本文链接位置：http://blog.csdn.net/wlsgzl/article/details/12835639）

读完这篇文章后，我也着手实现了一下，现贴出我的代码。

void DrawTorus(GLfloat fMajorRadius, GLfloat fMinorRadius, GLint nNumMajor, GLint nNumMinor)
{
	GLfloat fr=(fMajorRadius-fMinorRadius)/2;
	GLfloat fR=fr+fMinorRadius;

	GLfloat fMajorStep=2.0f*PI/nNumMajor;
	GLfloat fMinorStep=2.0f*PI/nNumMinor;

	GLfloat fMajorAngle=0.0f;
	GLfloat fMajorAngle2=0.0f;
	GLfloat fMinorAngle=0.0f;
	GLfloat fMinorAngle2=0.0f;

	GLfloat fX=0.0f;
	GLfloat fY=0.0f;
	GLfloat fZ=0.0f;
	GLfloat fX2=0.0f;
	GLfloat fY2=0.0f;
	GLfloat fZ2=0.0f;

	glBegin(GL_TRIANGLE_STRIP);
	for (fMajorAngle=0.0f;fMajorAngle<=2.0*PI;fMajorAngle+=fMajorStep)
	{
		for (fMinorAngle=0.0f;fMinorAngle<=2.0f*PI;fMinorAngle+=fMinorStep)
		{
			fX=(fR+fr*cos(fMinorAngle))*cos(fMajorAngle);
			fY=(fR+fr*cos(fMinorAngle))*sin(fMajorAngle);
			fZ=fr*sin(fMinorAngle);
			glVertex3f(fX,fY,fZ);

			fMajorAngle2=fMajorAngle+fMajorStep;
			fMinorAngle2=fMinorAngle+fMinorStep;

			fX2=(fR+fr*cos(fMinorAngle2))*cos(fMajorAngle2);
			fY2=(fR+fr*cos(fMinorAngle2))*sin(fMajorAngle2);
			fZ2=fr*sin(fMinorAngle2);
			glVertex3f(fX2,fY2,fZ2);
		}
	}
	glEnd();
}