opengl - 将锥体围绕球体旋转

Question

我想将圆锥体放在球体的表面上，例如：

我的尝试看起来像：

// black sphere
initMaterials2();
drawSphere(0.8);

// red cones
int n = 6;
initMaterials();
double angleIncrement = 360/n;
for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
        glPushMatrix();
        glRotatef(angleIncrement * i, 1, 0, 0);
        glRotatef(angleIncrement * j, 0, 0, 1);
        glTranslatef(0, 0.7, 0);
        drawCone(0.15, 0.6);
        glPopMatrix();
    }
}

如您所见，一堆锥体聚集在一侧......我认为我的旋转计算是错误的......我该如何解决它？

Answer 1

看起来我需要改变循环的顺序

int n = 3;
initMaterials();
double angleIncrement = 180/n;

for (int i = 0; i < n; i++) {
    glPushMatrix();
    glRotatef(angleIncrement * i, 0, 1, 0);
    for (double angle = 0; angle < 360; angle += 45) {
        glPushMatrix();
        glRotatef(angle, 1, 0, 0);
        glTranslatef(0, 0.7, 0);
        drawCone(0.15, 0.6);
        glPopMatrix();
    }
    glPopMatrix();
}