OpenGL画圆

最新推荐文章于 2025-07-13 10:54:43 发布

原创最新推荐文章于 2025-07-13 10:54:43 发布 · 3.8k 阅读

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void CShape2D::drawCircle() {
    static bool bDrawSemiCircle = false;
    glClear(GL_LINE_BIT);
    glBegin(GL_LINES);//可以改成GL_POINTS，具体含义参照gl文档
    //方法1
    //glPointSize(5.0f);//只对Begin的参数为GL_POINTS有用，glLineWidth：设置Line的宽度此时设置PointSize也是没有效果
    //if(bDrawSemiCircle) {
    //    glColor3f(0.0f, 0.0f, 1.0f);
    //    if(beginPoint_.x > -radius_) {
    //        for(GLfloat fVaule = radius_; fVaule >= beginPoint_.x; fVaule -= 0.0001f) {
    //            glVertex2f(fVaule, -sqrt(radius_ * radius_ - fVaule * fVaule));
    //        }
    //        beginPoint_.x -= 0.01f;
    //    }
    //} else {
    //    glColor3f(0.0f, 1.0f, 0.0f);
    //    if(beginPoint_.x > radius_) {
    //        beginPoint_.x = radius_;
    //        bDrawSemiCircle = true;
    //    } else {
    //        for(GLfloat fVaule = -radius_; fVaule <= beginPoint_.x; fVaule += 0.0001f) {
    //            glVertex2f(fVaule, sqrt(radius_ * radius_ - fVaule * fVaule));
    //        }
    //        beginPoint_.x += 0.01f;
    //    }
    //}
    //方法2
    glColor3f(1.0f, 0.0f, 0.0f);
    if(beginPoint_.x <= 2.0f * Pi) {
        for(GLfloat fVaule = 0; fVaule <= beginPoint_.x; fVaule += 0.001f) {
            glVertex2f(radius_ * cos(fVaule), radius_ * sin(fVaule)); 
        }
        beginPoint_.x += 0.02f;
    }
    glEnd();
    glFlush();
    glutSwapBuffers();
}

方法一还有一个bug就是首尾端点没连接到，自己接下来慢慢调试