#include <windows.h>
#include <gl/Gl.h>
#include <gl/glut.h>
#include <cmath>
int WinWidth = 500, WinHeight = 500;
typedef struct{float x;float y;}Point2D;
typedef struct{float x;float y;float z;}Point3D;
Point3D COP = {0,0,-200}; // Centre Of Projection is at (0,0,-200)
Point3D COP1 = {100,100,-200};
Point3D A,B,C,D,E,F,G,H; // Vertices of the cube
void InitCube(){
A.x = 0; A.y = 0; A.z = 0; // A(0,0,0)
B.x = 200; B.y = 0; B.z = 0; // B(200,0,0)
C.x = 200; C.y = 200; C.z = 0; // C(200,200,0)
D.x = 0; D.y = 200; D.z = 0; // D(0,200,0)
E.x = 0; E.y = 200; E.z = 200; // E(0,200,200)
F.x = 0; F.y = 0; F.z = 200; // F(0,0,200)
G.x = 200; G.y = 0; G.z = 200; // G(200,0,200)
H.x = 200; H.y = 200; H.z = 200; // H(200,200,200)
}
void DrawCube(Point2D A, Point2D B, Point2D C, Point2D D, Point2D E, Point2D F, Point2D G, Point2D H){
glPointSize(1.0);
glBegin(GL_LINE_LOOP);
//DRAWING FRONT FACE
glVertex2i(A.x, A.y); glVertex2i(B.x, B.y); glVertex2i(C.x, C.y); glVertex2i(D.x, D.y);
glEnd();
glBegin(GL_LINE_LOOP);
//DRAWING BACK FACE
glVertex2i(E.x, E.y); glVertex2i(F.x, F.y); glVertex2i(G.x, G.y); glVertex2i(H.x, H.y);
glEnd();
glBegin(GL_LINES);
//DRAWING OTHER LINES
glVertex2i(A.x, A.y); glVertex2i(F.x, F.y);
glVertex2i(B.x, B.y); glVertex2i(G.x, G.y);
glVertex2i(C.x, C.y); glVertex2i(H.x, H.y);
glVertex2i(D.x, D.y); glVertex2i(E.x, E.y);
glEnd();
glFlush();
}
Point2D Project_Perspective(Point3D p, Point3D CoP){
Point2D p2;
float d = abs(CoP.z); // The distance between the COP and orign
p2.x=(d*p.x)/(p.z+d);
p2.y=(d*p.y)/(p.z+d);
//.....wite necessary equations here for perspective transformation
return p2;
}
Point2D translate2D(Point2D p, float tx, float ty){
Point2D tp2;
//.....wite the equations for 2D translation
tp2.x=p.x+tx;
tp2.y=p.y+ty;
return tp2;
}
Point3D translate3D(Point3D p, float tx, float ty, float tz){
Point3D tp3;
//.....wite the equations for 3D translation
tp3.x=p.x+tx;
tp3.y=p.y+ty;
tp3.z=p.z+tz;
return tp3;
}
void keyboard(unsigned char key, int x, int y)
{
if (key == 'q' || key == 'Q')
exit(EXIT_SUCCESS);
}
void myMouse(int button, int state, int x, int y) {
if(state == GLUT_DOWN)
{
if(button == GLUT_LEFT_BUTTON)
{
/* Point2D translateA=translate2D(Projected_A,WinWidth/2, WinHeight/2);
Point2D translateA=translate2D(Projected_B,WinWidth/2, WinHeight/2);
Point2D translateA=translate2D(Projected_C,WinWidth/2, WinHeight/2);
Point2D translateA=translate2D(Projected_D,WinWidth/2, WinHeight/2);
Point2D translateA=translate2D(Projected_E,WinWidth/2, WinHeight/2);
Point2D translateA=translate2D(Projected_F,WinWidth/2, WinHeight/2);
Point2D translateA=translate2D(Projected_G,WinWidth/2, WinHeight/2);
Point2D translateA=translate2D(Projected_H,WinWidth/2, WinHeight/2);*/
}
else if (button == GLUT_RIGHT_BUTTON)
{
}
}
}
void myDisplay()
{
glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(0.0f, 0.0f, 0.0f);
Point2D Projected_A=Project_Perspective(A,COP);
Point2D Projected_B=Project_Perspective(B,COP);
Point2D Projected_C=Project_Perspective(C,COP);
Point2D Projected_D=Project_Perspective(D,COP);
Point2D Projected_E=Project_Perspective(E,COP);
Point2D Projected_F=Project_Perspective(F,COP);
Point2D Projected_G=Project_Perspective(G,COP);
Point2D Projected_H=Project_Perspective(H,COP);
DrawCube(
// Calculate the following values
//Q1
/*translate2D(Projected_A,WinWidth/2, WinHeight/2),
translate2D(Projected_B,WinWidth/2, WinHeight/2),
translate2D(Projected_C,WinWidth/2, WinHeight/2),
translate2D(Projected_D,WinWidth/2, WinHeight/2),
translate2D(Projected_E,WinWidth/2, WinHeight/2),
translate2D(Projected_F,WinWidth/2, WinHeight/2),
translate2D(Projected_G,WinWidth/2, WinHeight/2),
translate2D(Projected_H,WinWidth/2, WinHeight/2)*/
//Q3
translate2D(Project_Perspective(translate3D(A,-100, -100,0),COP1),WinWidth/2, WinHeight/2),
translate2D(Project_Perspective(translate3D(B,-100, -100,0),COP1),WinWidth/2, WinHeight/2),
translate2D(Project_Perspective(translate3D(C,-100,-100,0),COP1),WinWidth/2, WinHeight/2),
translate2D(Project_Perspective(translate3D(D,-100, -100,0),COP1),WinWidth/2, WinHeight/2),
translate2D(Project_Perspective(translate3D(E,-100, -100,0),COP1),WinWidth/2, WinHeight/2),
translate2D(Project_Perspective(translate3D(F,-100, -100,0),COP1),WinWidth/2, WinHeight/2),
translate2D(Project_Perspective(translate3D(G,-100,-100,0),COP1),WinWidth/2, WinHeight/2),
translate2D(Project_Perspective(translate3D(H,-100, -100,0),COP1),WinWidth/2, WinHeight/2)
);
}
int main( int argc, char ** argv ) {
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( WinWidth, WinHeight );
glutCreateWindow( "Projection of a Cube" );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
gluOrtho2D( 0, WinWidth, 0, WinHeight );
glViewport(0, 0, WinWidth, WinHeight);
InitCube();
glutKeyboardFunc(keyboard);
glutMouseFunc( myMouse );
glutDisplayFunc( myDisplay );
glutMainLoop();
return( 0 );
}
