#include<GL/glut.h>
#include<math.h>
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 normals[][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[][3] = {
{0.0, 0.0, 0.0}, {1.0, 0.0, 0.0},
{1.0, 1.0, 0.0}, {0.0, 1.1, 0.0}, {0.0, 0.0, 1.0},
{1.0, 0.0, 1.0}, {1.0, 1.0, 1.0}, {0.0, 1.0, 1.0}
};
void polygon(int a, int b, int c, int d){
glBegin(GL_POLYGON);
glColor3fv(colors[a]);
glNormal3fv(normals[a]);
glVertex3fv(vertices[a]);
glColor3fv(colors[b]);
glNormal3fv(normals[b]);
glVertex3fv(vertices[b]);
glColor3fv(colors[c]);
glNormal3fv(normals[c]);
glVertex3fv(vertices[c]);
glColor3fv(colors[d]);
glNormal3fv(normals[d]);
glVertex3fv(vertices[d]);
glEnd();
}
void colorcube(void){
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 GLdouble viewer[] = {0.0, 0.0, 5.0};
GLdouble eyex=0.0, eyey=0.0, eyez=5.0;
GLdouble atx=0.0, aty=0.0, atz=0.0;
GLdouble upx=0.0, upy=1.0, upz=0.0;
GLdouble tmp;
void display(void){
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
gluLookAt(eyex, eyey, eyez, atx, aty, atz, upx, upy, upz);
colorcube();
glFlush();
glutSwapBuffers();
}
void mouse(int btn, int state, int x, int y){
int tm_x, tm_y;
if(btn==GLUT_LEFT_BUTTON && state==GLUT_DOWN){
if(x<250 && eyex>-10 && eyez>0){
tm_x = eyex - (250-x)/100;
}else if(x>250 && eyex<10 && eyez>0){
tm_x = eyex + (x-250)/100;
}
if(y<250 && eyey<10){
tm_y = eyey + (250-y)/100;
}else if(y>250 && eyey>-10){
tm_y = eyey - (y-250)/100;
}
tmp = 25 - tm_x*tm_x - tm_y*tm_y;
if(tmp>0){
eyez = sqrt( tmp );
eyex = tm_x;
eyey = tm_y;
}
glutPostRedisplay();
}
display();
}
void myReshape(int w, int h){
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if(w<=h)
glFrustum(-2.0, 2.0, -2.0 * (GLfloat)h / (GLfloat)w, 2.0 * (GLfloat)h / (GLfloat)w, 2.0, 20.0);
else
glFrustum(-2.0, 2.0, -2.0 * (GLfloat)w / (GLfloat)h, 2.0 * (GLfloat)w / (GLfloat)h, 2.0, 20.0);
glMatrixMode(GL_MODELVIEW);
}
void main(int argc, char **argv){
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(500, 500);
glutCreateWindow("colorcube");
glutReshapeFunc(myReshape);
glutDisplayFunc(display);
glutMouseFunc(mouse);
glEnable(GL_DEPTH_TEST);
glutMainLoop();
}
