opengl - 在opengl中计算球体

Question

我想计算所有需要的顶点并用线连接它们，所以我最终想出了一个球体。有多少种方法可以做到？顶点之间的线也是直的；我怎样才能使它们“弯曲” 我知道我可以使用 glutWireSphere()，但我对实际计算顶点感兴趣。我想到的一种方法是将所有顶点手动放入一个数组中，但我想这不是它的完成方式。

Answer 1

复制并粘贴我最初在 Creating a 3D sphere in Opengl using Visual C++ 中编写的一些代码

class SolidSphere
{
protected
    std::vector<GLfloat> vertices;
    std::vector<GLfloat> normals;
    std::vector<GLfloat> texcoords;
    std::vector<GLushort> indices;

public:
    void SolidSphere(float radius, unsigned int rings, unsigned int sectors)
    {
        float const R = 1./(float)(rings-1);
        float const S = 1./(float)(sectors-1);
        int r, s;

        sphere_vertices.resize(rings * sectors * 3);
        sphere_normals.resize(rings * sectors * 3);
        sphere_texcoords.resize(rings * sectors * 2);
        std::vector<GLfloat>::iterator v = sphere_vertices.begin();
        std::vector<GLfloat>::iterator n = sphere_normals.begin();
        std::vector<GLfloat>::iterator t = sphere_texcoords.begin();
        for(r = 0; r < rings; r++) for(s = 0; s < sectors; s++) {
                float const y = sin( -M_PI_2 + M_PI * r * R );
                float const x = cos(2*M_PI * s * S) * sin( M_PI * r * R );
                float const z = sin(2*M_PI * s * S) * sin( M_PI * r * R );

                *t++ = s*S;
                *t++ = r*R;

                *v++ = x * radius;
                *v++ = y * radius;
                *v++ = z * radius;

                *n++ = x;
                *n++ = y;
                *n++ = z;
        }

        sphere_indices.resize(rings * sectors * 4);
        std:vector<GLushort>::iterator i = sphere_indices.begin();
        for(r = 0; r < rings; r++) for(s = 0; s < sectors; s++) {
                *i++ = r * sectors + s;
                *i++ = r * sectors + (s+1);
                *i++ = (r+1) * sectors + (s+1);
                *i++ = (r+1) * sectors + s;
        }
    }

    void draw(GLfloat x, GLfloat y, GLfloat z)
    {
        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();
        glTranslatef(x,y,z);

        glEnableClientState(GL_VERTEX_ARRAY);
        glEnableClientState(GL_NORMAL_ARRAY);
        glEnableClientState(GL_TEXTURE_COORD_ARRAY);

        glVertexPointer(3, GL_FLOAT, 0, &sphere_vertices[0]);
        glNormalPointer(GL_FLOAT, 0, &sphere_normals[0]);
        glTexCoordPointer(2, GL_FLOAT, 0, &sphere_texcoords[0]);
        glDrawElements(GL_QUADS, sphere_indices.size()/4, GL_UNSIGNED_SHORT, sphere_indices);
        glPopMatrix();
    }
}

how can I make them "curved"

你不能。所有 OpenGL 图元都是“仿射”的，即平面的或直线的。通过绘制具有足够分辨率的短而直的部分来模拟曲率。