为什么在glOrtho之后镜面不起作用？

我已经尝试了许多不同的GL_SPECULAR，但没有一个给我期望的闪亮效果。为什么在glOrtho之后镜面不起作用？

代码有什么问题？

GLfloat mat_ambient[]={0.329412, 0.223529, 0.027451};                                                       
GLfloat mat_diffuse[]={0.780392, 0.568627, 0.113725}; 
GLfloat mat_specular[]={0.992157, 0.941176, 0.807843}; 
GLfloat mat_shininess[]={0.21794872 * 128}; 


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

unsigned char last_key = 0; 
unsigned char channel = 'r'; 

void init(void) { 
    glClearColor(0.0, 0.0, 0.0, 0.0); 
    glShadeModel(GL_SMOOTH); 

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

    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); 
    glEnable(GL_DEPTH_TEST); 
} 


void display(void) { 
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); 
    const int length = 100; 
    glBegin(GL_QUADS); 
     glVertex2f(50, 50); 
     glVertex2f(50 + length, 50); 
     glVertex2f(50 + length, 50 + length); 
     glVertex2f(50, 50 + length); 
    glEnd(); 
    glFlush(); 
} 


void reshape(int w, int h) { 
    glViewport(0,0,(GLsizei) w,(GLsizei) h); 
    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    glOrtho(0, w, 0, h,-10.0,10.0); 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 
} 

int main(int argc,char**argv) { 
    glutInit(&argc,argv); 
    glutInitDisplayMode(GLUT_SINGLE|GLUT_RGBA|GLUT_DEPTH); 
    glutInitWindowSize(500,500); 
    glutInitWindowPosition(100,100); 
    glutCreateWindow("lighting demo"); 
    init(); 
    glutDisplayFunc(display); 
    glutReshapeFunc(reshape); 
    glutMainLoop(); 
    return 0; 
}

来源

2012-08-29 new_perl