//A.16  帶紋理立方體的旋轉程式
#include <stdlib.h>
#include <GL/glut.h> 
GLfloat planes[]= {-1.0, 0.0, 1.0, 0.0};
GLfloat planet[]= {0.0, -1.0,  0.0, 1.0};
GLfloat vertices[][3] = {{-1.0,-1.0,-1.0}, {1.0,-1.0,-1.0},
{1.0,1.0,-1.0}, {-1.0,1.0,-1.0}, {-1.0,-1.0,1.0}, 
{1.0,-1.0,1.0}, {1.0,1.0,1.0}, {-1.0,1.0,1.0}};
GLfloat colors[][4] = {{0.0,0.0,0.0,0.5}, {1.0,0.0,0.0,0.5},
{1.0,1.0,0.0,0.5}, {0.0,1.0,0.0,0.5},  {0.0,0.0,1.0,0.5}, 
{1.0,0.0,1.0,0.5}, {1.0,1.0,1.0,0.5},  {0.0,1.0,1.0,0.5}};
void polygon(int a, int b, int c, int d)
{
	glBegin(GL_POLYGON);
	glColor4fv(colors[a]);
	glTexCoord2f(0.0,0.0); 
	glVertex3fv(vertices[a]);
	glColor4fv(colors[b]);
	glTexCoord2f(0.0,1.0);
	glVertex3fv(vertices[b]);
	glColor4fv(colors[c]);
	glTexCoord2f(1.0,1.0); 
	glVertex3fv(vertices[c]);
	glColor4fv(colors[d]);
	glTexCoord2f(1.0,0.0); 
	glVertex3fv(vertices[d]);
	glEnd();
}
void colorcube(void)
{
	/* map vertices to faces */
	polygon(0,3,2,1);
	polygon(2,3,7,6);
	polygon(0,4,7,3);
	polygon(1,2,6,5);
	polygon(4,5,6,7);
	polygon(0,1,5,4);
} 
static GLfloat theta[] = {0.0,0.0,0.0};
static GLint axis = 2;
void display(void)
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glLoadIdentity();
	glRotatef(theta[0], 1.0, 0.0, 0.0);
	glRotatef(theta[1], 0.0, 1.0, 0.0);
	glRotatef(theta[2], 0.0, 0.0, 1.0);
	colorcube();
	glutSwapBuffers();
}
void spinCube()
{
	theta[axis] += 2.0;
	if( theta[axis] > 360.0 ) theta[axis] -= 360.0;
	glutPostRedisplay();
}
void mouse(int btn, int state, int x, int y)
{
	if(btn==GLUT_LEFT_BUTTON && state == GLUT_DOWN) axis = 0;
	if(btn==GLUT_MIDDLE_BUTTON && state == GLUT_DOWN) axis = 1;
	if(btn==GLUT_RIGHT_BUTTON && state == GLUT_DOWN) axis = 2;
}
void myReshape(int w, int h)
{
	glViewport(0, 0, w, h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	if (w <= h)
		glOrtho(-2.0, 2.0, -2.0 * (GLfloat) h / (GLfloat) w,
		2.0 * (GLfloat) h / (GLfloat) w, -10.0, 10.0);
	else 
		glOrtho(-2.0 * (GLfloat) w / (GLfloat) h,
		2.0 * (GLfloat) w / (GLfloat) h, -2.0, 2.0, -10.0, 10.0);
	glMatrixMode(GL_MODELVIEW);
}
void key(unsigned char k, int x, int y)
{
	if(k == '1') glutIdleFunc(spinCube);
	if(k == '2') glutIdleFunc(NULL);
	if(k == 'q') exit(0);
}
void main(int argc, char **argv)
{
	GLubyte image[64][64][3];
	int i, j, r, c;
	for(i=0;i<64;i++)
	{
		for(j=0;j<64;j++)
		{
			c = ((((i&0x8)==0)^((j&0x8))==0))*255;
			image[i][j][0]= (GLubyte) c;
			image[i][j][1]= (GLubyte) c;
			image[i][j][2]= (GLubyte) c;
		}
	}
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
	glutInitWindowSize(500, 500);
	glutCreateWindow("colorcube");
	glutReshapeFunc(myReshape);
	glutDisplayFunc(display);
	glutIdleFunc(spinCube);
	glutMouseFunc(mouse);
	glEnable(GL_DEPTH_TEST);
	glEnable(GL_TEXTURE_2D);
	glTexImage2D(GL_TEXTURE_2D,0,3,64,64,0,GL_RGB,GL_UNSIGNED_BYTE, 
		image);
	glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT); 
	glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
	glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
	glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST); 
	glutKeyboardFunc(key);
	glClearColor(1.0,1.0,1.0,1.0);
	glutMainLoop();
}