[OpenGL]利用地球绕日旋转做的简单的光照效果

#include < gl/glut.h> 

#define WIDTH 400 
#define HEIGHT 400 

static GLfloat angle = 0.0f; 

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

	// 创建透视效果视图 
	glMatrixMode(GL_PROJECTION); 
	glLoadIdentity(); 
	gluPerspective(90.0f, 1.0f, 1.0f, 20.0f); 
	glMatrixMode(GL_MODELVIEW); 
	glLoadIdentity(); 
	gluLookAt(0.0, 5.0, -10.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0); 

	// 定义太阳光源，它是一种白色的光源 
	{ 
		GLfloat sun_light_position[] = {0.0f, 0.0f, 0.0f, 1.0f}; 
		GLfloat sun_light_ambient[]  = {0.0f, 0.0f, 0.0f, 1.0f}; 
		GLfloat sun_light_diffuse[]  = {1.0f, 1.0f, 1.0f, 1.0f}; 
		GLfloat sun_light_specular[] = {1.0f, 1.0f, 1.0f, 1.0f}; 

		glLightfv(GL_LIGHT0, GL_POSITION, sun_light_position); 
		glLightfv(GL_LIGHT0, GL_AMBIENT,  sun_light_ambient); 
		glLightfv(GL_LIGHT0, GL_DIFFUSE,  sun_light_diffuse); 
		glLightfv(GL_LIGHT0, GL_SPECULAR, sun_light_specular); 

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

	// 定义太阳的材质并绘制太阳 
	{ 
		GLfloat sun_mat_ambient[]  = {0.0f, 0.0f, 0.0f, 1.0f}; 
		GLfloat sun_mat_diffuse[]  = {0.0f, 0.0f, 0.0f, 1.0f}; 
		GLfloat sun_mat_specular[] = {0.0f, 0.0f, 0.0f, 1.0f}; 
		GLfloat sun_mat_emission[] = {0.5f, 0.0f, 0.0f, 1.0f}; 
		GLfloat sun_mat_shininess  = 0.0f; 

		glMaterialfv(GL_FRONT, GL_AMBIENT,   sun_mat_ambient); 
		glMaterialfv(GL_FRONT, GL_DIFFUSE,   sun_mat_diffuse); 
		glMaterialfv(GL_FRONT, GL_SPECULAR,  sun_mat_specular); 
		glMaterialfv(GL_FRONT, GL_EMISSION,  sun_mat_emission); 
		glMaterialf (GL_FRONT, GL_SHININESS, sun_mat_shininess); 

		glutSolidSphere(2.0, 40, 32); 
	} 

	// 定义地球的材质并绘制地球 
	{ 
		GLfloat earth_mat_ambient[]  = {0.0f, 0.0f, 0.5f, 1.0f}; 
		GLfloat earth_mat_diffuse[]  = {0.0f, 0.0f, 0.5f, 1.0f}; 
		GLfloat earth_mat_specular[] = {0.0f, 0.0f, 1.0f, 1.0f}; 
		GLfloat earth_mat_emission[] = {0.0f, 0.0f, 0.0f, 1.0f}; 
		GLfloat earth_mat_shininess  = 30.0f; 

		glMaterialfv(GL_FRONT, GL_AMBIENT,   earth_mat_ambient); 
		glMaterialfv(GL_FRONT, GL_DIFFUSE,   earth_mat_diffuse); 
		glMaterialfv(GL_FRONT, GL_SPECULAR,  earth_mat_specular); 
		glMaterialfv(GL_FRONT, GL_EMISSION,  earth_mat_emission); 
		glMaterialf (GL_FRONT, GL_SHININESS, earth_mat_shininess); 
				glRotatef(angle, 0.0f, -1.0f, 0.0f); 
		glTranslatef(5.0f, 0.0f, 0.0f); 
		glutSolidSphere(2.0, 40, 32); 
	} 

	glutSwapBuffers(); 
} 
void myIdle(void) 
{ 
	angle += 1.0f; 
	if( angle >= 360.0f ) 
		angle = 0.0f; 
	myDisplay(); 
} 

int main(int argc, char* argv[]) 
{ 
	glutInit(&argc, argv); 
	glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE); 
	glutInitWindowPosition(200, 200); 
	glutInitWindowSize(WIDTH, HEIGHT); 
	glutCreateWindow("OpenGL光照演示"); 
	glutDisplayFunc(&myDisplay); 
	glutIdleFunc(&myIdle); 
	glutMainLoop(); 
	return 0; 
}