CGR Ass 7 - 3D Transformations

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

// Transformation variables
float tx = 0.0f, ty = 0.0f, tz = 0.0f; // Translation
float sx = 1.0f, sy = 1.0f, sz = 1.0f; // Scaling
float angle = 0.0f;                    // Rotation angle
char axis = 'x';                       // Rotation axis

// Function to draw a 3D cube
void drawCube() {
    glBegin(GL_QUADS);
    // Front face (z = 1.0)
    glColor3f(1.0f, 0.0f, 0.0f); // Red
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);
    glVertex3f(-1.0f, 1.0f, 1.0f);

    // Back face (z = -1.0)
    glColor3f(0.0f, 1.0f, 0.0f); // Green
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, -1.0f, -1.0f);

    // Top face (y = 1.0)
    glColor3f(0.0f, 0.0f, 1.0f); // Blue
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, 1.0f, -1.0f);

    // Bottom face (y = -1.0)
    glColor3f(1.0f, 1.0f, 0.0f); // Yellow
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, -1.0f);

    // Right face (x = 1.0)
    glColor3f(1.0f, 0.0f, 1.0f); // Magenta
    glVertex3f(1.0f, -1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);

    // Left face (x = -1.0)
    glColor3f(0.0f, 1.0f, 1.0f); // Cyan
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glEnd();
}

// Display callback
void display() {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();

    // Apply transformations
    glTranslatef(tx, ty, tz); // Translation
    glScalef(sx, sy, sz);     // Scaling

    // Rotation
    if (axis == 'x') glRotatef(angle, 1.0f, 0.0f, 0.0f);
    else if (axis == 'y') glRotatef(angle, 0.0f, 1.0f, 0.0f);
    else if (axis == 'z') glRotatef(angle, 0.0f, 0.0f, 1.0f);

    // Draw the cube
    drawCube();

    glutSwapBuffers();
}

// Keyboard input callback
void keyboard(unsigned char key, int x, int y) {
    switch (key) {
        case 'w': ty += 0.1f; break; // Move up
        case 's': ty -= 0.1f; break; // Move down
        case 'a': tx -= 0.1f; break; // Move left
        case 'd': tx += 0.1f; break; // Move right
        case 'z': tz += 0.1f; break; // Move closer
        case 'x': tz -= 0.1f; break; // Move farther
        case '+': sx += 0.1f; sy += 0.1f; sz += 0.1f; break; // Scale up
        case '-': sx -= 0.1f; sy -= 0.1f; sz -= 0.1f; break; // Scale down
        case 'r': angle += 5.0f; break; // Rotate
        case 'X': axis = 'x'; break; // Rotate about X-axis
        case 'Y': axis = 'y'; break; // Rotate about Y-axis
        case 'Z': axis = 'z'; break; // Rotate about Z-axis
        case 27: exit(0); // Exit on 'Esc' key
    }
    glutPostRedisplay();
}

// Reshape callback
void reshape(int w, int h) {
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45.0, (double)w / (double)h, 1.0, 200.0);
    glMatrixMode(GL_MODELVIEW);
}

// Main function
int main(int argc, char** argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(800, 600);
    glutCreateWindow("3D Cube Transformations");

    glEnable(GL_DEPTH_TEST);
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutKeyboardFunc(keyboard);

    glutMainLoop();
    return 0;
}