OPENGL问题（光照球的问题）
以下是光照球的代码，为何在init（）中定义的变量，比如GLfloat mat_specular[] ，将这个变量的定义放在下面的函数后面的时候（如放在 glClearColor (0.0, 0.0, 0.0, 0.0);之后时，会出现错误:\ss\ewqedwasdad\simpleopengl\light.c(77) : error C2275: 'GLfloat' : illegal use of this type as an expression
c:\program files\microsoft visual studio\vc98\include\gl\gl.h(53) : see declaration of 'GLfloat'
D:\ss\ewqedwasdad\simpleopengl\light.c(77) : error C2146: syntax error : missing ';' before identifier 'spot_direction'
D:\ss\ewqedwasdad\simpleopengl\light.c(77) : error C2065: 'spot_direction' : undeclared identifier
D:\ss\ewqedwasdad\simpleopengl\light.c(77) : error C2059: syntax error : ']'
D:\ss\ewqedwasdad\simpleopengl\light.c(90) : warning C4047: 'function' : 'const float *' differs in levels of indirection from 'int '
D:\ss\ewqedwasdad\simpleopengl\light.c(90) : warning C4024: 'glLightfv' : different types for formal and actual parameter 3
执行 cl.exe 时出错.
Creating browse info file...

simpleopengl.exe - 1 error(s), 0 warning(s)
，难道opengl中变量不可以定义在被调用之前的任何位置，而必须定义在开始么



#include <GL/glut.h>
#include <stdlib.h>

/* Initialize material property, light source, lighting model,
* and depth buffer.
*/
void init(void)
{
GLfloat mat_specular[] = { 1.0, 1.0, 1.0,1.0 };
GLfloat mat_shininess[] = { 50.0 };
GLfloat light_position[] = { 1.0, 1.0, 1.0, 0.0 };
GLfloat white_light[]={1.0,1.0,1.0,1.0};
GLfloat lmodel_ambient[]={0.1,0.1,0.1,1.0};
GLfloat light_position2[] = { -2.0, -2.0, 1.0, 1.0 };
GLfloat white_light2[] = {1.0, 1.0, 1.0, 1.0};
GLfloat light_ambient[] = { 0.2, 0.2, 0.2, 1.0};
GLfloat spot_direction[]= {-1.0, -1.0, 0};
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);
glLightfv(GL_LIGHT0, GL_POSITION, light_position);
//glLightfv(GL_LIGHT0,GL_POSITION,light_position);
glLightfv(GL_LIGHT0,GL_DIFFUSE,white_light);
glLightfv(GL_LIGHT0,GL_SPECULAR,white_light);




glLightfv(GL_LIGHT1, GL_POSITION, light_position2);
//glLightfv(GL_LIGHT0,GL_POSITION,light_position);
glLightfv(GL_LIGHT1,GL_DIFFUSE,white_light2);
glLightfv(GL_LIGHT1,GL_SPECULAR,white_light2);
glLightfv(GL_LIGHT1,GL_AMBIENT,light_ambient);

glLightf(GL_LIGHT1,GL_CONSTANT_ATTENUATION,1.5);
glLightf(GL_LIGHT1,GL_LINEAR_ATTENUATION,0.5);
glLightf(GL_LIGHT1,GL_QUADRATIC_ATTENUATION,0.2);
glLightf(GL_LIGHT1,GL_SPOT_CUTOFF,45);
glLightfv(GL_LIGHT1,GL_SPOT_DIRECTION,spot_direction);

glLightf(GL_LIGHT1,GL_SPOT_EXPONENT,2.0);

glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_LIGHT1);
glEnable(GL_DEPTH_TEST);
}

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

glutSolidSphere (1.0, 20, 16);
glFlush ();
}

void reshape (int w, int h)
{
glViewport (0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode (GL_PROJECTION);
glLoadIdentity();
if (w <= h)
glOrtho (-1.5, 1.5, -1.5*(GLfloat)h/(GLfloat)w,1.5*(GLfloat)h/(GLfloat)w, -10.0, 10.0);
//glOrtho(-1.5,1.5,-1.5,1.5*(GLfloat)h/(GLfloat)w,-10,10);
else
// glOrtho(-1.5,1.5*(GLfloat)w/(GLfloat)h,-1.5,1.5,-10,10);
glOrtho (-1.5*(GLfloat)w/(GLfloat)h,1.5*(GLfloat)w/(GLfloat)h, -1.5, 1.5, -10.0, 10.0);

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();
}

void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 27:
exit(0);
break;
}
}

int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize (500, 500);
glutInitWindowPosition (100, 100);
glutCreateWindow (argv[0]);
init ();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutMainLoop();
return 0;
}


[解决办法]
只有C++才能随用随定义（包括初始化），C不允许。