error C2091: 函数返回函数
void glBresenham(int x1,int x2,int y1,int y2)()
{
int x=x1, y=y1;
int dx=x2-x1, dy=y2-y1, dT=2*(dy-dx), dS=2*dy;
int d=2*dy-dx;
glBegin(GL_POINTS);
glVertex2i(x1,y1);
while(x<x2)
{
x++;
if(d<0)
d+=dS;
else
{
y++;
d+=dT;
}
glVertex2i(x,y);
}
glEnd();
glFlush();
}

[解决办法]
void glBresenham(int x1,int x2,int y1,int y2)()//多了个括号
==>
void glBresenham(int x1,int x2,int y1,int y2)
[解决办法]
void glBresenham(int x1,int x2,int y1,int y2)，去掉尾巴处的括号