Hi all,
I am implementing mouse rotations to rotate a small scene consisting of a sphere and a plane. The scene rotates around its local axes, which gives weird rotations. I want to rotate the scene in a fixed coordinate system. Please suggest any ideas. I am attaching the code below:
#include <GL/glut.h>
#include <stdio.h>
#include <stdlib.h>
void drawScene(void);
GLfloat eyex = 0.0, eyey = 0.0, eyez = 5.0;
int check = 0;
float stateX, stateY, rotateX = 0.0, rotateY = 0.0;
void init(void)
{
glClearColor(0.0, 0.0, 0.0, 0.0);
glShadeModel(GL_SMOOTH);
GLfloat light_position[] = {16.0, 3.0, 4.0, 1.0};
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};
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);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(eyex, eyey, eyez, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
glRotatef(rotateY, 0.0, 1.0, 0.0);
glRotatef(rotateX, 1.0, 0.0, 0.0);
drawScene();
glutSwapBuffers();
glFlush();
}
void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 100.0);
}
void drawScene(void)
{
GLfloat mat_specular[] = {1.0, 1.0, 1.0, 1.0};
GLfloat mat_amb_diff[] = {0.4, 0.0, 0.0, 1.0};
GLfloat mat_shininess[] = {100.0};
glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, mat_amb_diff);
glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
glutSolidSphere(0.5, 30, 30);
glBegin(GL_QUADS);
glNormal3f(0.0, 1.0, 0.0);
glVertex3f(-2.0, -1.0, 2.0);
glNormal3f(0.0, 1.0, 0.0);
glVertex3f(2.0, -1.0, 2.0);
glNormal3f(0.0, 1.0, 0.0);
glVertex3f(2.0, -1.0, -2.0);
glNormal3f(0.0, 1.0, 0.0);
glVertex3f(-2.0, -1.0, -2.0);
glEnd();
}
void mouse(int button, int state, int i, int j)
{
if(state == GLUT_DOWN)
{
switch(button)
{
case GLUT_LEFT_BUTTON:
{
check = 1;
stateX = i;
stateY = j;
}
break;
case GLUT_RIGHT_BUTTON:
check = 2;
break;
default:
break;
}
}
}
void motion(int i, int j)
{
if(check == 1)
{
rotateX = rotateX > 360.0 ? rotateX-360.0 : rotateX < -360.0 ? rotateX+=360.0 : rotateX;
rotateY = rotateY > 360.0 ? rotateY-360.0 : rotateY < -360.0 ? rotateY+=360.0 : rotateY;
if(j!=stateY)
rotateX = rotateX + (j - stateY) * 0.1;
if(i!=stateX)
rotateY = rotateY + (i - stateX) * 0.1;
printf("rotateX, rotateY: %f %f
", rotateX, rotateY);
stateX = i;
stateY = j;
glutPostRedisplay();
}
else if(check == 2)
{
printf("Rotate y-axis
");
}
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(512, 512);
glutInitWindowPosition(100, 100);
glutCreateWindow(argv[0]);
init();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
// glutKeyboardFunc(keyboard);
glutMotionFunc(motion);
glutMouseFunc(mouse);
glutMainLoop();
return 0;
}