opengl图像显示不出来

在绘制Nurbs曲线后显示不出来  是什么原因
//控制点
GLfloat controlPoints[7][3]={
{-1.2f,0.8f,0.0f},{-0.8f,-2.0f,0.0f},{-0.4f,0.4f,0.0f},
        {0.0f,2.0f,0.0f},{0.4f,0.4f,0.0f},{0.8f,-2.0f,0.0f},
{1.2f,0.8f,0.0f}
};
//结点
GLfloat knots[14]={0.0f,0.0f,0.0f,0.0f,0.0f,0.0f,
1.0f,1.0f,1.0f,1.0f,1.0f,1.0f};
glColor3f(0.0f,0.0f,1.0f);
//创建NURBS对象
GLUnurbsObj   *theNurb;
theNurb=gluNewNurbsRenderer();
//属性
gluNurbsProperty(theNurb,GLU_SAMPLING_TOLERANCE,10.0);
//绘制
glNewList(1,GL_COMPILE);
gluBeginCurve(theNurb);
 gluNurbsCurve(theNurb,14,knots,3,(float*)controlPoints,7,
 GL_MAP1_VERTEX_3);
 gluEndCurve(theNurb);
 glEndList();
 glCallList(1);

5 个解决方案

#1

(float*)controlPoints --> controlPoints[0] 看看

#2

(float*)controlPoints --> controlPoints[0]  这个什么意思  不解   可以帮我解释下下么  先谢谢拉

#3

就是(float*)controlPoints替换为controlPoints[0]

#4

也是一样显示不出

#5

Drawing a NURBS Surface: surface.c 

#include <GL/gl.h>
#include <GL/glu.h>
#include "aux.h"

GLfloat ctlpoints[4][4][3];
GLUnurbsObj *theNurb;

void init_surface(void)
{
    int u, v;
    for (u = 0; u < 4; u++) {
        for (v = 0; v < 4; v++) {
            ctlpoints[u][v][0] = 2.0*((GLfloat)u - 1.5);
            ctlpoints[u][v][1] = 2.0*((GLfloat)v - 1.5);

        if ( (u == 1 || u == 2) && (v == 1 || v == 2))
            ctlpoints[u][v][2] = 3.0;
        else
            ctlpoints[u][v][2] = -3.0;
        }
    } 
}

void myinit(void)
{
    GLfloat mat_diffuse[] = { 0.7, 0.7, 0.7, 1.0 };
    GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 };
    GLfloat mat_shininess[] = { 100.0 };

    glClearColor (0.0, 0.0, 0.0, 1.0);
    glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
    glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);

    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glDepthFunc(GL_LEQUAL);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_AUTO_NORMAL);
    glEnable(GL_NORMALIZE);
    init_surface();

    theNurb = gluNewNurbsRenderer();
    gluNurbsProperty(theNurb, GLU_SAMPLING_TOLERANCE, 25.0);
    gluNurbsProperty(theNurb, GLU_DISPLAY_MODE, GLU_FILL);
}

void display(void)
{
    GLfloat knots[8] = {0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0};

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glPushMatrix();
        glRotatef(330.0, 1.,0.,0.);
        glScalef (0.5, 0.5, 0.5);

        gluBeginSurface(theNurb);
        gluNurbsSurface(theNurb, 
            8, knots,
            8, knots,
            4 * 3,
            3,
            &ctlpoints[0][0][0], 
            4, 4,
            GL_MAP2_VERTEX_3);
        gluEndSurface(theNurb);

    glPopMatrix();
    glFlush();
}

void myReshape(GLsizei w, GLsizei h)
{
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective (45.0, (GLdouble)w/(GLdouble)h, 3.0, 8.0);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef (0.0, 0.0, -5.0);
}


int main(int argc, char** argv)
{
    auxInitDisplayMode (AUX_SINGLE | AUX_RGBA);
    auxInitPosition (0, 0, 500, 500);
    auxInitWindow (argv[0]);
    myinit();
    auxReshapeFunc (myReshape);
    auxMainLoop(display);
}