UC知道opengl编程如何使得一个矩形始终正对着观察者？
来源：百度知道 编辑：UC知道 时间：2024/05/17 02:05:03
opengl编程如何使得一个矩形始终正对着观察者？
opengl三维图程序编写时如何实现以某个点为定点绘制一个矩形，不论场景如何沿x轴或者y轴旋转保证该矩形
始终正对着观察着的屏幕？
我已经做到只沿着一个轴旋转的情况，可是两个轴同时转以后就不行了。
矩形坐标如下：
glVertex3f(0.0f,0.0f,1.0f);
glVertex3f(cos(double(yrot/180*PI)),0.0f,1.0f+sin(double(yrot/180*PI)));
glVertex3f(cos(double(yrot/180*PI)),1.0f,1.0f+sin(double(yrot/180*PI)));
glVertex3f(0.0f,1.0f,1.0f);
其中yrot即为沿着y周旋转的角度。
opengl三维图程序编写时如何实现以某个点为定点绘制一个矩形，不论场景如何沿x轴或者y轴旋转保证该矩形
始终正对着观察着的屏幕？
我已经做到只沿着一个轴旋转的情况，可是两个轴同时转以后就不行了。
矩形坐标如下：
glVertex3f(0.0f,0.0f,1.0f);
glVertex3f(cos(double(yrot/180*PI)),0.0f,1.0f+sin(double(yrot/180*PI)));
glVertex3f(cos(double(yrot/180*PI)),1.0f,1.0f+sin(double(yrot/180*PI)));
glVertex3f(0.0f,1.0f,1.0f);
其中yrot即为沿着y周旋转的角度。
This is called "billboard", you need only simply multiply the vertex with a matrix, the link of tutorial is the following, very simple.
http://nehe.gamedev.net/data/articles/article.asp?article=19
there is chinese version of that artical also, called " opengl hong pi shu"
simply saying: load current matrix and transport, then multiply with your vertex.
da bu liao zhong wen, bu hao yi si