2013-03-21 117 views
4

中着色當我嘗試在OpenGL中使用多邊形時遇到問題。我不知道如何解釋這個,但我所有的頂點都與開始的頂點連接。當我嘗試着色物體時,問題就會發生。我想繪製一個簡單的對象。OpenGL GL_POLYGON凹多邊形不在

void TOP (float x1, float y1, float x2, float h,float n) 
{ 
    float r = x2-x1; 
    if(n==1){glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);} // FOR FILL OR NO FILL OBJECT 
    glBegin(GL_POLYGON); 
    glVertex2f(x1,y1); 
    glVertex2f(x2,y1); 
    glVertex2f(x2,y1+h/7); 
    y1=y1+h/7; 
    glVertex2f(x2-r/5,y1+h/7); 
    x2=x2-r/5; y1=y1+h/7; 
    glVertex2f(x2,y1+2*h/7); 
    y1=y1+2*h/7; 
     glVertex2f(x2+r/5,y1+h/7); 
     y1=y1+h/7; x2=x2+r/5; 
     glVertex2f(x2,y1+2*h/7); 
cout<<y1<<endl; 
     y1=y1+2*h/7; 
     glVertex2f(x2-r/5,y1); x2=x2-r/5; 
     glVertex2f(x2,y1-h/7); y1=y1-h/7; 
     glVertex2f(x2-r/5,y1);x2=x2-r/5; 
     glVertex2f(x2,y1+h/7); y1=y1+h/7; 
     glVertex2f(x2-r/5,y1);x2=x2-r/5; 

     glVertex2f(x2,y1-h/7); y1=y1-h/7; 
     glVertex2f(x2-r/5,y1);x2=x2-r/5; 
     glVertex2f(x2,y1+h/7); y1=y1+h/7; 
     glVertex2f(x2-r/5,y1);x2=x2-r/5; 
     glVertex2f(x2,y1-2*h/7);y1=y1-2*h/7; 
     glVertex2f(x2+r/5,y1-h/7);y1=y1-h/7; x2=x2+r/5; 
     glVertex2f(x2,y1-2*h/7); y1=y1-2*h/7; 
     glVertex2f(x2-r/5,y1-h/7); y1=y1-h/7;x2=x2-r/5; 
      glVertex2f(x2,y1-h/7); 

    glEnd(); 
} 

輸出:

http://i.stack.imgur.com/BLMSJ.png

回答