在opengl中计算一个球体 [英] calculating a sphere in opengl

问题描述

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这一点？而且顶点之间的线会是直的;我怎么能让他们弯曲我知道我可以使用glutWireSphere（），但我有兴趣实际计算顶点。我想到的一种方式是将所有顶点手动放入数组中，但我认为这不是它的完成方式。 解决方案 div>

复制并粘贴我最初写在使用Visual C ++在Opengl中创建3D球体

  class SolidSphere 
 {
保护
 std :: vector< GLfloat>顶点; 
 std :: vector< GLfloat>法线; 
 std :: vector< GLfloat> texcoords; 
 std :: vector< GLushort>指数; 
 $ b $ public：
 void SolidSphere（float radius，unsigned int rings，unsigned int sector）
 {
 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（）; （s = 0; s <扇区; s ++）{
 float const y = sin（-M_PI_2 + M_PI * r * R）的情况下，对于（r = 0; 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（）;对于（s = 0; s <扇区; s ++）{
 * i ++ = r *扇区+ s;对于（r = 0; r  * i ++ = r * sector +（s + 1）; 
 * i ++ =（r + 1）* sector +（s + 1）; 
 * i ++ =（r + 1）* sector + s; 
 
 
 $ b 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（）; 
} 
} 
  

我该如何制作他们弯曲

你不能。所有OpenGL原语都是仿射的，即平面或直线。通过绘制具有足够分辨率的短直线部分来模拟曲率。

I want to calculate all the vertices needed and connect them with lines, so I eventually come up with a sphere. How many ways are there to do it? And also the lines between the vertices, will be straight; how can I make them "curved" I know that I can use glutWireSphere(), but I am interested in actually calculating the vertices. A way that I thought about it, was to put all the vertices manually in an array, but I guess that is not the way it's done.

解决方案

Copy and Pasting some code I originally wrote in Creating a 3D sphere in Opengl using Visual C++

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"

You can't. All OpenGL primitives are "affine", i.e. planar or straight. Curvature is emulated by drawing short, straight sections with sufficient resolution.

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