Question

我正在C中使用OpenGL编写太阳系模拟。有一个存储所有行星信息的主体数组。我希望行星轨道倾斜一定的角度，然而从结果来看，行星和轨道一直围绕（0,0,0）旋转。我怎么能解决这个问题？这是我的一些代码。

这里是数组＆＃39;

的定义

typedef struct {
    char    name[20];       /* name */
    GLfloat r, g, b;        /* colour */
    GLfloat orbital_radius; /* distance to parent body (km) */
    GLfloat orbital_tilt;   /* angle of orbit wrt ecliptic (deg) */
    GLfloat orbital_period; /* time taken to orbit (days) */
    GLfloat radius;         /* radius of body (km) */
    GLfloat axis_tilt;      /* tilt of axis wrt body's orbital plane (deg) */
    GLfloat rot_period;     /* body's period of rotation (days) */
    GLint   orbits_body;    /* identifier of parent body */
    GLfloat spin;           /* current spin value (deg) */
    GLfloat orbit;          /* current orbit value (deg) */
} body;

以下是精确绘制行星的功能。它需要绕轴旋转才能旋转，轨道也需要倾斜。

void drawBody(int n)
{
    glRotatef(bodies[n].orbital_tilt,0,0,1); //toilet
    drawOrbit(n);
    glRotatef(bodies[n].orbit,0,1,0);//orb
    glTranslatef(bodies[n].orbital_radius,0,0); 
    // self axis tilt
    glRotatef(bodies[n].axis_tilt,0,0,1);//atilt

    /* rotate on its own */
    glPushMatrix();
        glRotatef(bodies[n].spin,0,1,0); //self-spin
        glRotatef(90,1,0,0); //vert
        glColor3f(bodies[n].r,bodies[n].g,bodies[n].b);
        glLineWidth(1.0);
        glutWireSphere(bodies[n].radius,15,15);
    glPopMatrix();
}

和我的绘制轨道功能：</ p>

void drawOrbit (int n)
{ /* Draws a polygon to approximate the circular
   orbit of body "n" */
    float angle = 2*PI/ORBIT_POLY_SIDES;
    float r = bodies[n].orbital_radius;
    float i ;

    glPushMatrix();
    glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
    glBegin(GL_POLYGON);
        glColor3f(bodies[n].r,bodies[n].g,bodies[n].b);
        for (i = 0; i < 2*PI; i+=angle){
            glVertex3f(r*sin(i),0,r*cos(i));
        }
    glEnd();
    glPopMatrix();
    /* This is for you to complete. */
}

如何倾斜旋转平面？

0 个答案: