使用OpenGL画出一个带有光照的茶壶，并且能够用键盘进行平移缩放和旋转

下面是一个使用OpenGL画出带有光照的茶壶的示例代码。该程序能够响应键盘事件进行平移缩放和旋转。

#include <GL/glut.h>

GLfloat light_position[] = { 1.0, 1.0, 1.0, 0.0 };
GLfloat light_ambient[] = { 0.0, 0.0, 0.0, 1.0 };
GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat light_specular[] = { 1.0, 1.0, 1.0, 1.0 };

GLfloat mat_ambient[] = { 0.7, 0.7, 0.7, 1.0 };
GLfloat mat_diffuse[] = { 0.8, 0.8, 0.8, 1.0 };
GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat mat_shininess[] = { 100.0 };

GLfloat xrot = 0.0, yrot = 0.0, zrot = 0.0;
GLfloat xscale = 1.0, yscale = 1.0, zscale = 1.0;
GLfloat xtrans = 0.0, ytrans = 0.0, ztrans = 0.0;

void init(void)
{
    glEnable(GL_DEPTH_TEST);

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

    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, mat_shininess);
}

void display(void)
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glPushMatrix();
    glTranslatef(xtrans, ytrans, ztrans);
    glScalef(xscale, yscale, zscale);
    glRotatef(xrot, 1.0, 0.0, 0.0);
    glRotatef(yrot, 0.0, 1.0, 0.0);
    glRotatef(zrot, 0.0, 0.0, 1.0);

    glutSolidTeapot(1.0);

    glPopMatrix();

    glutSwapBuffers();
}

void reshape(int w, int h)
{
    glViewport(0, 0, (GLsizei)w, (GLsizei)h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60.0, (GLfloat)w / (GLfloat)h, 1.0, 20.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef(0.0, 0.0, -5.0);
}

void keyboard(unsigned char key, int x, int y)
{
    switch (key)
    {
    case 'x':
        xrot += 5.0;
        break;
    case 'X':
        xrot -= 5.0;
        break;
    case 'y':
        yrot += 5.0;
        break;
    case 'Y':
        yrot -= 5.0;
        break;
    case 'z':
        zrot += 5.0;
        break;
    case 'Z':
        zrot -= 5.0;
        break;
    case 's':
        xscale *= 0.9;
        yscale *= 0.9;
        zscale *= 0.9;
        break;
    case 'S':
        xscale /= 0.9;
        yscale /= 0.9;
        zscale /= 0.9;
        break;
    case 't':
        xtrans += 0.1;
        break;
    case 'T':
        xtrans -= 0.1;
        break;
    case 'u':
        ytrans += 0.1;
        break;
    case 'U':
        ytrans -= 0.1;
        break;
    case 'v':
        ztrans += 0.1;
        break;
    case 'V':
        ztrans -= 0.1;
        break;
    case 27:
        exit(0);
        break;
    default:
        break;
    }

    glutPostRedisplay();
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(500, 500);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("Teapot with Light");

    init();

    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutKeyboardFunc(keyboard);

    glutMainLoop();
    return 0;
}

在这个程序中，我们使用 `glutSolidTeapot()` 函数画出了一个茶壶。我们使用 `glTranslatef()`、`glRotatef()` 和 `glScalef()` 函数实现平移、旋转和缩放操作。我们使用 `gluPerspective()` 函数设置透视投影。我们使用 `glutKeyboardFunc()` 函数响应键盘事件。