OPENGL 绘制基本图元

glColor3f(1.0,0.0,0.0);//设置颜色

glBegin(GL_TRIANGLES);//开始绘制,参数可选

glEnd();

1.绘制矩形

glRectf(-0.5f, -0.5f, 0.5f, 0.5f);

2.绘制点

glVertex2f(-1.0,-1.0);//设置第一个顶点的坐标为(-1.0,-1.0)

3.绘制线

glVertex2f(0.0,-1.0);//设置第1个顶点的坐标为(0.0,-1.0)
glVertex2f(-0.5,1.0);//设置第2个顶点的坐标为(-0.5,1.0)

4.绘制多边形

glVertex2f(-1.0,-1.0);//设置第一个顶点的坐标为(-1.0,-1.0)
glVertex2f(0.0,-1.0);//设置第二个顶点的坐标为(0.0,-1.0)
glVertex2f(-0.5,1.0);//设置第三个顶点的坐标为(-0.5,1.0)

5.绘制圆

#include
const int n = 20;
const GLfloat R = 0.5f;
const GLfloat Pi = 3.1415926536f;
void myDisplay(void)
{
     int i;
     glClear(GL_COLOR_BUFFER_BIT);
     glBegin(GL_POLYGON);
     for(i=0; i
         glVertex2f(R*cos(2*Pi/n*i), R*sin(2*Pi/n*i));
     glEnd();
     glFlush();
}


6.绘制五角星

#include
const GLfloat Pi = 3.1415926536f;
void myDisplay(void)
{
     GLfloat a = 1 / (2-2*cos(72*Pi/180));
     GLfloat bx = a * cos(18 * Pi/180);
     GLfloat by = a * sin(18 * Pi/180);
     GLfloat cy = -a * cos(18 * Pi/180);
     GLfloat
         PointA[2] = { 0, a },
         PointB[2] = { bx, by },
         PointC[2] = { 0.5, cy },
         PointD[2] = { -0.5, cy },
         PointE[2] = { -bx, by };

     glClear(GL_COLOR_BUFFER_BIT);
     // 按照A->C->E->B->D->A的顺序,可以一笔将五角星画出
     glBegin(GL_LINE_LOOP);
         glVertex2fv(PointA);
         glVertex2fv(PointC);
         glVertex2fv(PointE);
         glVertex2fv(PointB);
         glVertex2fv(PointD);
     glEnd();
     glFlush();
}
7.绘制正玄线

#include
const GLfloat factor = 0.1f;
void myDisplay(void)
{
     GLfloat x;
     glClear(GL_COLOR_BUFFER_BIT);
     glBegin(GL_LINES);
         glVertex2f(-1.0f, 0.0f);
         glVertex2f(1.0f, 0.0f);         // 以上两个点可以画x轴
         glVertex2f(0.0f, -1.0f);
         glVertex2f(0.0f, 1.0f);         // 以上两个点可以画y轴
     glEnd();
     glBegin(GL_LINE_STRIP);
     for(x=-1.0f/factor; x<1.0f/factor; x+=0.01f)
     {
         glVertex2f(x*factor, sin(x)*factor);
     }
     glEnd();
     glFlush();
}


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