tema 3.2 abcd [GRAFICA]

#include <windows.h>
#include <gl/freeglut.h>
#include <cmath>
#include <iostream>

GLint winWidth = 800, winHeight = 800;
GLfloat xx0 = 13.0, yy0 = 11.0, zz0 = 14.0;
GLfloat xref = 3.0, yref = 1.0, zref = 4.0;
GLfloat Vx = 8.0, Vy = 0.0, Vz = -8.0;

GLfloat xwMin = -10.0, ywMin = -10.0, xwMax = 10.0, ywMax = 10.0;

GLfloat dnear = 0.0, dfar = 20.0;

void init(void)
{
    glClearColor(1.0, 1.0, 1.0, 0.0);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(xx0, yy0, zz0, xref, yref, zref, Vx, Vy, Vz);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(xwMin, xwMax, ywMin, ywMax, dnear, dfar);
}



class Punct
{
public:
    float x, y, z;

    Punct(int xx, int yy, int zz)
    {
        x = xx;
        y = yy;
        z = zz;
    }

    Punct()
    {
        x = y = z = 0;
    }
};

void desen()
{

    Punct A(3, 1, 0), B(-2, 2, 4), C(0, 0, 4);

    glLineWidth(3.0);
    glPointSize(3.0);

    //a) determinati punctul M astfel incat sa fie in interiorul triunghiului ABC sau pe laturi
    Punct M;
    M.x = (B.x + C.x) / 2;
    M.y = (B.y + C.y) / 2;
    M.z = (B.z + C.z) / 2;

    glPointSize(10.0);
    glBegin(GL_POINTS);
    glColor3f(1.0, 0.5, 0.5);
    glVertex3i(M.x, M.y, M.z);
    glEnd();

    //b) deteminati D in planul triunghiului asa incat ABDC(atentie la ordine!!!) sa fie un patrulater convex

    Punct D; //am construit punctul D a.i. sa fie simetricul varfului A
    D.x = 2 * M.x - A.x;
    D.y = 2 * M.y - A.y;
    D.z = 2 * M.z - A.z;

    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    glBegin(GL_POLYGON);
    glColor3f(1.0, 0.0, 0.0);
    glVertex3i(A.x, A.y, A.z);
    glColor3f(0.0, 1.0, 0.0);
    glVertex3i(B.x, B.y, B.z);
    glColor3f(1.0, 0.0, 1.0);
    glVertex3i(D.x, D.y, D.z);
    glColor3f(0.0, 0.0, 1.0);
    glVertex3i(C.x, C.y, C.z);
    glEnd();

    //c) construiti normala n la patrulaterul ABDC

    Punct Normala;
    Normala.x = (A.y * B.z + B.y * C.z + C.y * A.z) - (C.y * B.z + A.y * C.z + B.y * A.z);
    Normala.y = (C.x * B.z + A.x * C.z + B.x * A.z) - (A.x * B.z + B.x * C.z + C.x * A.z);
    Normala.z = (A.x * B.y + B.x * C.y + C.x * A.y) - (C.x * B.y + A.x * C.y + B.x * A.y);
    float radical = std::sqrt(Normala.x * Normala.x + Normala.y * Normala.y + Normala.z * Normala.z);
    Normala.x = Normala.x / radical;
    Normala.y = Normala.y / radical;
    Normala.z = Normala.z / radical;

    std::cout << "Normala la patrulater este n = " << Normala.x << "i + " << Normala.y << "j + "<< Normala.z << "k.\n";

    //d) folosind M si n construiti un punct O1 in fata patrulaterului si un punct O2 in spatele acestuia.
    Punct O1(M.x * 7 * Normala.x, M.y * 7 * Normala.y, M.z * 7 * Normala.z);
    Punct O2(M.x * (-7) * Normala.x, M.y * (-7) * Normala.y, M.z * (-7) * Normala.z);

    std::cout << "Punctul O1 de coordonate" << O1.x << "," << O1.y << ", " << O1.z << "\n";
    std::cout << "Punctul O2 de coordonate" << O2.x << "," << O2.y << ", " << O2.z << "\n";


    glFlush();
}

void main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowPosition(50, 50);
    glutInitWindowSize(winWidth, winHeight);
    glutCreateWindow("Poligoane in context 3D. Fata si spatele unui poligon");

    init();
    glClear(GL_COLOR_BUFFER_BIT);
    glutDisplayFunc(desen);
    glutMainLoop();
}