OpenGL：從OpenGL中顯示的對象中檢索原始頂點和索引緩衝區

我對長代碼示例表示歉意。下面是我的示例代碼：OpenGL：從OpenGL中顯示的對象中檢索原始頂點和索引緩衝區
#include <iostream> 
#include <cstdlib> 
#include <GL/glut.h> 
using namespace std; 


//#include "glutint.h" 

/* Rim, body, lid, and bottom data must be reflected in x and 
    y; handle and spout data across the y axis only. */ 

static int patchdata[][16] = 
{ 
    /* rim */ 
    {102, 103, 104, 105, 4, 5, 6, 7, 8, 9, 10, 11, 
    12, 13, 14, 15}, 
    /* body */ 
    {12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 
    24, 25, 26, 27}, 
    {24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 
    37, 38, 39, 40}, 
    /* lid */ 
    {96, 96, 96, 96, 97, 98, 99, 100, 101, 101, 101, 
    101, 0, 1, 2, 3,}, 
    {0, 1, 2, 3, 106, 107, 108, 109, 110, 111, 112, 
    113, 114, 115, 116, 117}, 
    /* bottom */ 
    {118, 118, 118, 118, 124, 122, 119, 121, 123, 126, 
    125, 120, 40, 39, 38, 37}, 
    /* handle */ 
    {41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 
    53, 54, 55, 56}, 
    {53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 
    28, 65, 66, 67}, 
    /* spout */ 
    {68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 
    80, 81, 82, 83}, 
    {80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 
    92, 93, 94, 95} 
}; 
/* *INDENT-OFF* */ 

static float cpdata[][3] = 
{ 
    {0.2, 0, 2.7}, {0.2, -0.112, 2.7}, {0.112, -0.2, 2.7}, {0, 
    -0.2, 2.7}, {1.3375, 0, 2.53125}, {1.3375, -0.749, 2.53125}, 
    {0.749, -1.3375, 2.53125}, {0, -1.3375, 2.53125}, {1.4375, 
    0, 2.53125}, {1.4375, -0.805, 2.53125}, {0.805, -1.4375, 
    2.53125}, {0, -1.4375, 2.53125}, {1.5, 0, 2.4}, {1.5, -0.84, 
    2.4}, {0.84, -1.5, 2.4}, {0, -1.5, 2.4}, {1.75, 0, 1.875}, 
    {1.75, -0.98, 1.875}, {0.98, -1.75, 1.875}, {0, -1.75, 
    1.875}, {2, 0, 1.35}, {2, -1.12, 1.35}, {1.12, -2, 1.35}, 
    {0, -2, 1.35}, {2, 0, 0.9}, {2, -1.12, 0.9}, {1.12, -2, 
    0.9}, {0, -2, 0.9}, {-2, 0, 0.9}, {2, 0, 0.45}, {2, -1.12, 
    0.45}, {1.12, -2, 0.45}, {0, -2, 0.45}, {1.5, 0, 0.225}, 
    {1.5, -0.84, 0.225}, {0.84, -1.5, 0.225}, {0, -1.5, 0.225}, 
    {1.5, 0, 0.15}, {1.5, -0.84, 0.15}, {0.84, -1.5, 0.15}, {0, 
    -1.5, 0.15}, {-1.6, 0, 2.025}, {-1.6, -0.3, 2.025}, {-1.5, 
    -0.3, 2.25}, {-1.5, 0, 2.25}, {-2.3, 0, 2.025}, {-2.3, -0.3, 
    2.025}, {-2.5, -0.3, 2.25}, {-2.5, 0, 2.25}, {-2.7, 0, 
    2.025}, {-2.7, -0.3, 2.025}, {-3, -0.3, 2.25}, {-3, 0, 
    2.25}, {-2.7, 0, 1.8}, {-2.7, -0.3, 1.8}, {-3, -0.3, 1.8}, 
    {-3, 0, 1.8}, {-2.7, 0, 1.575}, {-2.7, -0.3, 1.575}, {-3, 
    -0.3, 1.35}, {-3, 0, 1.35}, {-2.5, 0, 1.125}, {-2.5, -0.3, 
    1.125}, {-2.65, -0.3, 0.9375}, {-2.65, 0, 0.9375}, {-2, 
    -0.3, 0.9}, {-1.9, -0.3, 0.6}, {-1.9, 0, 0.6}, {1.7, 0, 
    1.425}, {1.7, -0.66, 1.425}, {1.7, -0.66, 0.6}, {1.7, 0, 
    0.6}, {2.6, 0, 1.425}, {2.6, -0.66, 1.425}, {3.1, -0.66, 
    0.825}, {3.1, 0, 0.825}, {2.3, 0, 2.1}, {2.3, -0.25, 2.1}, 
    {2.4, -0.25, 2.025}, {2.4, 0, 2.025}, {2.7, 0, 2.4}, {2.7, 
    -0.25, 2.4}, {3.3, -0.25, 2.4}, {3.3, 0, 2.4}, {2.8, 0, 
    2.475}, {2.8, -0.25, 2.475}, {3.525, -0.25, 2.49375}, 
    {3.525, 0, 2.49375}, {2.9, 0, 2.475}, {2.9, -0.15, 2.475}, 
    {3.45, -0.15, 2.5125}, {3.45, 0, 2.5125}, {2.8, 0, 2.4}, 
    {2.8, -0.15, 2.4}, {3.2, -0.15, 2.4}, {3.2, 0, 2.4}, {0, 0, 
    3.15}, {0.8, 0, 3.15}, {0.8, -0.45, 3.15}, {0.45, -0.8, 
    3.15}, {0, -0.8, 3.15}, {0, 0, 2.85}, {1.4, 0, 2.4}, {1.4, 
    -0.784, 2.4}, {0.784, -1.4, 2.4}, {0, -1.4, 2.4}, {0.4, 0, 
    2.55}, {0.4, -0.224, 2.55}, {0.224, -0.4, 2.55}, {0, -0.4, 
    2.55}, {1.3, 0, 2.55}, {1.3, -0.728, 2.55}, {0.728, -1.3, 
    2.55}, {0, -1.3, 2.55}, {1.3, 0, 2.4}, {1.3, -0.728, 2.4}, 
    {0.728, -1.3, 2.4}, {0, -1.3, 2.4}, {0, 0, 0}, {1.425, 
    -0.798, 0}, {1.5, 0, 0.075}, {1.425, 0, 0}, {0.798, -1.425, 
    0}, {0, -1.5, 0.075}, {0, -1.425, 0}, {1.5, -0.84, 0.075}, 
    {0.84, -1.5, 0.075} 
}; 

static float tex[2][2][2] = 
{ 
    { {0, 0}, 
    {1, 0}}, 
    { {0, 1}, 
    {1, 1}} 
}; 

/* *INDENT-ON* */ 

static void 
teapot(GLint grid, GLdouble scale, GLenum type) 
{ 
    float p[4][4][3], q[4][4][3], r[4][4][3], s[4][4][3]; 
    long i, j, k, l; 

    glPushAttrib(GL_ENABLE_BIT | GL_EVAL_BIT); 
    glEnable(GL_AUTO_NORMAL); 
    glEnable(GL_NORMALIZE); 
    glEnable(GL_MAP2_VERTEX_3); 
    glEnable(GL_MAP2_TEXTURE_COORD_2); 
    glPushMatrix(); 
    glRotatef(270.0, 1.0, 0.0, 0.0); 
    glScalef(0.5 * scale, 0.5 * scale, 0.5 * scale); 
    glTranslatef(0.0, 0.0, -1.5); 
    for (i = 0; i < 10; i++) { 
    for (j = 0; j < 4; j++) { 
     for (k = 0; k < 4; k++) { 
     for (l = 0; l < 3; l++) { 
      p[j][k][l] = cpdata[patchdata[i][j * 4 + k]][l]; 
      q[j][k][l] = cpdata[patchdata[i][j * 4 + (3 - k)]][l]; 
      if (l == 1) 
      q[j][k][l] *= -1.0; 
      if (i < 6) { 
      r[j][k][l] = 
       cpdata[patchdata[i][j * 4 + (3 - k)]][l]; 
      if (l == 0) 
       r[j][k][l] *= -1.0; 
      s[j][k][l] = cpdata[patchdata[i][j * 4 + k]][l]; 
      if (l == 0) 
       s[j][k][l] *= -1.0; 
      if (l == 1) 
       s[j][k][l] *= -1.0; 
      } 
     } 
     } 
    } 
    glMap2f(GL_MAP2_TEXTURE_COORD_2, 0, 1, 2, 2, 0, 1, 4, 2, 
     &tex[0][0][0]); 
    glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 0, 1, 12, 4, 
     &p[0][0][0]); 
    glMapGrid2f(grid, 0.0, 1.0, grid, 0.0, 1.0); 
    glEvalMesh2(type, 0, grid, 0, grid); 
    glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 0, 1, 12, 4, 
     &q[0][0][0]); 
    glEvalMesh2(type, 0, grid, 0, grid); 
    if (i < 6) { 
     glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 0, 1, 12, 4, 
     &r[0][0][0]); 
     glEvalMesh2(type, 0, grid, 0, grid); 
     glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 0, 1, 12, 4, 
     &s[0][0][0]); 
     glEvalMesh2(type, 0, grid, 0, grid); 
    } 
    } 
    glPopMatrix(); 
    glPopAttrib(); 
} 

/* CENTRY */ 
void APIENTRY 
_glutSolidTeapot(GLdouble scale) 
{ 
    teapot(14, scale, GL_FILL); 
} 

void APIENTRY 
_glutWireTeapot(GLdouble scale) 
{ 
    teapot(10, scale, GL_LINE); 
} 

// function prototypes 
void disp(void); 
void keyb(unsigned char key, int x, int y); 


// window identifier 
static int win; 

int main(int argc, char **argv){ 

    ////////// 
    // INIT // 
    ////////// 

    // initialize glut 
    glutInit(&argc, argv); 

    // specify the display mode to be RGB and single buffering 
    // we use single buffering since this will be non animated 
    glutInitDisplayMode(GLUT_RGBA | GLUT_SINGLE); 

    // define the size 
    glutInitWindowSize(500,500); 

    // the position where the window will appear 
    glutInitWindowPosition(100,100); 


    // if we would want fullscreen: 
    // glutFullScreen(); 

    // create the window, set the title and keep the 
    // window identifier. 
    win = glutCreateWindow("Yet another teapot"); 

    ////////////// 
    // CALLBACK // 
    ////////////// 

    glutDisplayFunc(disp); 
    glutKeyboardFunc(keyb); 

    //////////// 
    // OPENGL // 
    //////////// 

    // define the color we use to clearscreen 
    glClearColor(0.0,0.0,0.0,0.0); 



    // enter the main loop 
    glutMainLoop(); 

    return 0; 
} 


void disp(void){ 

    // do a clearscreen 
    glClear(GL_COLOR_BUFFER_BIT); 

    // draw something 

    _glutWireTeapot(0.5); 
    // glutSolidTeapot(0.5); 
    // glutWireSphere(0.5,100,100); 
    // glutSolidSphere(0.5,100,100); 
    // glutWireTorus(0.3,0.5,100,100); 
    // glutSolidTorus(0.3,0.5,100,100); 
    // glutWireIcosahedron(); 
    // glutSolidIcosahedron(); 
    // glutWireDodecahedron(); 
    // glutSolidDodecahedron(); 
    // glutWireCone(0.5,0.5,100,100); 
    // glutSolidCone(0.5,0.5,100,100); 
    // glutWireCube(0.5); 
    // glutSolidCube(0.5); 
} 

void keyb(unsigned char key, int x, int y){ 
    cout << "Pressed key " << key << " on coordinates (" << x << "," << y << ")"; 
    cout << endl; 
    if(key == 'q'){ 
     cout << "Got q,so quitting " << endl; 
     glutDestroyWindow(win); 
     exit(0); 
    } 
}
http://mindfuck.de-brauwer.be/articles/glut/
http://www.it.freebsd.org/pub/Unix/NetBSD/NetBSD-current/xsrc/external/mit/MesaGLUT/dist/src/glut/beos/glut_teapot.c
相關引用。
謝謝米莎Koshelev
來源
2010-07-18 Миша Кошелев