使用glNormal3f法向量绘制立方体

Posted 2022-12-11 ambercctv

#if 0
#include <GLFW/glut.h>

GLfloat light_diffuse[] = 1.0, 0.0, 0.0, 1.0 ;  /* Red diffuse light. */
GLfloat light_position[] = 0.0, 0.0, 5.0, 0.0 ;  /* Infinite light location. */

GLuint cl1;

GLuint idleCounter = 0;

void
list1(void)

    glBegin(GL_QUADS);
    glNormal3f(-1, 0, 0);
    glVertex3f(-1, -1, 1);
    glVertex3f(-1, -1, -1);
    glVertex3f(-1, 1, -1);
    glVertex3f(-1, 1, 1);

    glNormal3f(0, 1, 0);
    glVertex3f(-1, 1, 1);
    glVertex3f(-1, 1, -1);
    glVertex3f(1, 1, -1);
    glVertex3f(1, 1, 1);

    glNormal3f(1, 0, 0);
    glVertex3f(1, 1, 1);
    glVertex3f(1, 1, -1);
    glVertex3f(1, -1, -1);
    glVertex3f(1, -1, 1);

    //4

    glNormal3f(0, -1, 0);
    glVertex3f(1, -1, 1);
    glVertex3f(1, -1, -1);
    glVertex3f(-1, -1, -1);
    glVertex3f(-1, -1, 1);

    //5 +z

    glNormal3f(0, 0, 0);
    glVertex3f(-1, -1, 1);
    glVertex3f(-1, 1, 1);
    glVertex3f(1, 1, 1);
    glVertex3f(1, -1, 1);
    
    //6 -z
    glNormal3f(1, 0, 0);
    glVertex3f(-1, -1, -1);
    glVertex3f(-1, 1, -1);
    glVertex3f(1, 1, -1);
    glVertex3f(1, -1, -1);
    glEnd();

    glFlush();
    glutSwapBuffers();

void display(void)

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    //glCallList(cl1);
    list1();

void idle(void)

    if ((idleCounter++ % 0x10000) == 0)
    
        glRotatef(0.1, 0.0, 0.0, 1.0);
        glutPostRedisplay();
    

void reshape(void)

void
init(void)

    /* Enable a single OpenGL light. */
    glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
    glLightfv(GL_LIGHT0, GL_POSITION, light_position);
    
    glEnable(GL_LIGHT0);
    glEnable(GL_LIGHTING);

    /* Use depth buffering for hidden surface elimination. */
    glEnable(GL_DEPTH_TEST);

    cl1 = glGenLists(1);
    glNewList(cl1, GL_COMPILE);
    list1();
    glEndList();

    /* Setup the view of the cube. */
    glMatrixMode(GL_PROJECTION);
    gluPerspective( /* field of view in degree */ 40.0,
        /* aspect ratio */ 1.0,
        /* Z near */ 1.0, /* Z far */ 10.0);
    glMatrixMode(GL_MODELVIEW);
    gluLookAt(0, 0.0, -10.0,  /* eye is at (0,0,5) */
        0.0, 0.0, 0.0,      /* center is at (0,0,0) */
        0.0, 1.0, 0.0);      /* up is in positive Y direction */

#if 0
    gluLookAt(-10, 0.0, 0.0,  /* eye is at (0,0,5) */
        0.0, 0.0, 0.0,      /* center is at (0,0,0) */
        0.0, 0.0, 1.0);      /* up is in positive Y direction */
    GLfloat light_position[] = -5.0, 0.0, 0.0, 0.0 ;
#endif

                            /* Adjust cube position to be asthetic angle. */
    //glTranslatef(0.0, 0.0, -1.0);
    //glRotatef(60, 1.0, 0.0, 0.0);
    //glRotatef(-20, 0.0, 0.0, 1.0);

int
main(int argc, char **argv)

    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutCreateWindow("3D lighted cube");
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutIdleFunc(idle);
    init();
    glutMainLoop();
    return 0;             /* ANSI C requires main to return int. */

#endif