ComputerGraphicsLab/prog4.cpp at main · Aneesh-M-Bhat/ComputerGraphicsLab · GitHub

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

GLfloat vertices[][3] = {{-1, -1, -1},
                         {1, -1, -1},
                         {1, 1, -1},
                         {-1, 1, -1},
                         {-1, -1, 1},
                         {1, -1, 1},
                         {1, 1, 1},
                         {-1, 1, 1}};

GLfloat colors[][3] = {{0, 0, 0},
                       {1, 0, 0},
                       {1, 1, 0},
                       {0, 1, 0},
                       {0, 0, 1},
                       {1, 0, 1},
                       {1, 1, 1},
                       {0, 1, 1}};

GLfloat theta[] = {0.0, 0.0, 0.0};
GLint axis = 2;
GLdouble viewer[] = {0.0, 0.0, 5.0};

void drawPolygon(int a, int b, int c, int d)
{
    glBegin(GL_POLYGON);
    glColor3fv(colors[a]);
    glVertex3fv(vertices[a]);
    glColor3fv(colors[b]);
    glVertex3fv(vertices[b]);
    glColor3fv(colors[c]);
    glVertex3fv(vertices[c]);
    glColor3fv(colors[d]);
    glVertex3fv(vertices[d]);
    glEnd();
}

void colorcube(void)
{
    // Order is anticlockwise while watching the respective face, order is important both the below give same end cube

    drawPolygon(0, 3, 2, 1);
    drawPolygon(0, 4, 7, 3);
    drawPolygon(5, 4, 0, 1);
    drawPolygon(2, 3, 7, 6);
    drawPolygon(1, 2, 6, 5);
    drawPolygon(4, 5, 6, 7);

    // drawPolygon(5, 6, 7, 4);
    // drawPolygon(1, 2, 6, 5);
    // drawPolygon(0, 3, 2, 1);
    // drawPolygon(4, 7, 3, 0);
    // drawPolygon(1, 5, 4, 0);
    // drawPolygon(6, 2, 3, 7);
}

void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    gluLookAt(viewer[0], viewer[1], viewer[2], 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
    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();
    glFlush();
    glutSwapBuffers();
}

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;
    theta[axis] += 2.0;
    if (theta[axis] > 360.0)
        theta[axis] -= 360.0;
    glutPostRedisplay();
}

void keys(unsigned char key, int x, int y)
{
    if (key == 'x')
        viewer[0] -= 1.0;
    if (key == 'X')
        viewer[0] += 1.0;
    if (key == 'y')
        viewer[1] -= 1.0;
    if (key == 'Y')
        viewer[1] += 1.0;
    if (key == 'z')
        viewer[2] -= 1.0;
    if (key == 'Z')
        viewer[2] += 1.0;
    glutPostRedisplay();
}

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 init(){
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(500, 500);
    glutCreateWindow("Colorcube Viewer");
    glutReshapeFunc(myReshape);
    glutDisplayFunc(display);
    glutMouseFunc(mouse);
    glutKeyboardFunc(keys);
    glEnable(GL_DEPTH_TEST);
    glutMainLoop();
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    init();
}