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I'm trying to get all the quads filled. At the moment it colors only the right side of the box. Here is my code.

void showPictureW()
{
    glDepthMask(true);
    glColor3f(1,0,0);

    //front
    glBegin( GL_QUADS );
    glVertex3f(-1.2,0.8,-4.0);
    glVertex3f(2,0.8,-4.0);
    glVertex3f(2,0.0,-4.0);
    glVertex3f(-1.2,0.0,-4.0);
    glEnd();

    //back
    glBegin( GL_QUADS );
    glVertex3f(1.8,1.0,-4.0); //2
    glVertex3f(1.8,1.8,-4.0);
    glVertex3f(5.0,1.8,-4.0);
    glVertex3f(5.0,1.0,-4.0);
    glEnd();

    //left
    glBegin( GL_QUADS );
    glVertex3f(1.8,1.8,-4.0);
    glVertex3f(1.8,1.0,-4.0);
    glVertex3f(-1.2,0.0,-4.0);
    glVertex3f(-1.2,0.8,-4.0);
    glEnd();

    //right
    glBegin( GL_QUADS );
    glVertex3f(2.0,0.8,-4.0);
    glVertex3f(2.0,0.0,-4.0);
    glVertex3f(5.0,1.0,-4.0);
    glVertex3f(5.0,1.8,-4.0);
    glEnd();
}

static void resize(int width, int height)
{
    const float ar = (float) width / (float) height;

    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glFrustum(-ar, ar, -1.0, 1.0, 1.0, 100.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

static void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glPushMatrix();
    glTranslated(-3.5,-3,0);
    showPictureW();
    glPopMatrix();

    glutSwapBuffers();
}

static void idle(void)
{
    glutPostRedisplay();
}

    const GLfloat light_ambient[]  = { 0.0f, 0.0f, 0.0f, 1.0f };
    const GLfloat light_diffuse[]  = { 1.0f, 1.0f, 1.0f, 1.0f };
    const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
    const GLfloat light_position[] = { 2.0f, 5.0f, 5.0f, 0.0f };

    const GLfloat mat_ambient[]    = { 0.7f, 0.7f, 0.7f, 1.0f };
    const GLfloat mat_diffuse[]    = { 0.8f, 0.8f, 0.8f, 1.0f };
    const GLfloat mat_specular[]   = { 1.0f, 1.0f, 1.0f, 1.0f };
    const GLfloat high_shininess[] = { 100.0f };

/* Program entry point */

int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitWindowSize(800,600);
    glutInitWindowPosition(10,10);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);

    glutCreateWindow("FreeGLUT Shapes");

    glutReshapeFunc(resize);
    glutDisplayFunc(display);
    glutKeyboardFunc(key);
    glutIdleFunc(idle);

    glClearColor(1,1,1,1);
    glEnable(GL_CULL_FACE);
    glCullFace(GL_BACK);

    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    glEnable(GL_LIGHT0);
    glEnable(GL_NORMALIZE);
    glEnable(GL_COLOR_MATERIAL);
    glEnable(GL_LIGHTING);

    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);
    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);
    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
    glLightfv(GL_LIGHT0, GL_POSITION, light_position);

    glMaterialfv(GL_FRONT, GL_AMBIENT,   mat_ambient);
    glMaterialfv(GL_FRONT, GL_DIFFUSE,   mat_diffuse);
    glMaterialfv(GL_FRONT, GL_SPECULAR,  mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);

    glutMainLoop();

    return EXIT_SUCCESS;
}

When I use GL_LINE_LOOP the box displays fine. It's when I change to quads it doesn't output properly.

4

1 回答 1

1 
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);

确保所有四边形都具有“正确”的逆时针绕组。

或者禁用剔除。

于 2013-06-17T16:25:34.757 回答