# include <iostream.h>
# include <graphics.h>
# include <conio.h>
# include <math.h>
# define n1 -1.0
# define n2 1.0
# define n3 1.0
# define x0 1.0
# define y0 1.0
# define z0 1.0
# define a 0.2
# define b 0.2
# define c 0.2
void show_screen( );
void draw_cube(int [8][3]);
void draw_pyramid(int [5][3]);
void get_projected_point(int&,int&,int&);
void multiply_matrices(constfloat[4],constfloat[4][4],float[4]);
void Line(constint,constint,constint,constint);
int main( )
{
int driver=VGA;
int mode=VGAHI;
initgraph(&driver,&mode,"..\\Bgi");
show_screen( );
int cube[8][3]={
{370,200,50}, // front left top
{470,200,50}, // front right top
{470,300,50}, // front right bottom
{370,300,50}, // front left bottom
{370,200,-50}, // back left top
{470,200,-50}, // back right top
{470,300,-50}, // back right bottom
{370,300,-50} // back left bottom
};
setcolor(15);
draw_cube(cube);
settextstyle(0,0,1);
outtextxy(400,320,"Cube");
int pyramid[5][3]={
{120,300,50}, // base front left
{220,300,50}, // base front right
{220,300,-50}, // base back right
{120,300,-50}, // base back left
{170,150,0} // top
};
setcolor(15);
draw_pyramid(pyramid);
settextstyle(0,0,1);
outtextxy(135,320,"Pyramid");
getch( );
closegraph( );
return 0;
}
/************************************************************************///---------------------------- draw_cube( ) --------------------------///************************************************************************/void draw_cube(int edge_points[8][3])
{
for(int i=0;i<8;i++)
get_projected_point(edge_points[i][0],
edge_points[i][1],edge_points[i][2]);
Line(edge_points[0][0],edge_points[0][1],
edge_points[1][0],edge_points[1][1]);
Line(edge_points[1][0],edge_points[1][1],
edge_points[2][0],edge_points[2][1]);
Line(edge_points[2][0],edge_points[2][1],
edge_points[3][0],edge_points[3][1]);
Line(edge_points[3][0],edge_points[3][1],
edge_points[0][0],edge_points[0][1]);
Line(edge_points[4][0],edge_points[4][1],
edge_points[5][0],edge_points[5][1]);
Line(edge_points[5][0],edge_points[5][1],
edge_points[6][0],edge_points[6][1]);
Line(edge_points[6][0],edge_points[6][1],
edge_points[7][0],edge_points[7][1]);
Line(edge_points[7][0],edge_points[7][1],
edge_points[4][0],edge_points[4][1]);
Line(edge_points[0][0],edge_points[0][1],
edge_points[4][0],edge_points[4][1]);
Line(edge_points[1][0],edge_points[1][1],
edge_points[5][0],edge_points[5][1]);
Line(edge_points[2][0],edge_points[2][1],
edge_points[6][0],edge_points[6][1]);
Line(edge_points[3][0],edge_points[3][1],
edge_points[7][0],edge_points[7][1]);
}
/************************************************************************///-------------------------- draw_pyramid( ) -------------------------///************************************************************************/void draw_pyramid(int edge_points[5][3])
{
for(int i=0;i<5;i++)
get_projected_point(edge_points[i][0],
edge_points[i][1],edge_points[i][2]);
Line(edge_points[0][0],edge_points[0][1],
edge_points[1][0],edge_points[1][1]);
Line(edge_points[1][0],edge_points[1][1],
edge_points[2][0],edge_points[2][1]);
Line(edge_points[2][0],edge_points[2][1],
edge_points[3][0],edge_points[3][1]);
Line(edge_points[3][0],edge_points[3][1],
edge_points[0][0],edge_points[0][1]);
Line(edge_points[0][0],edge_points[0][1],
edge_points[4][0],edge_points[4][1]);
Line(edge_points[1][0],edge_points[1][1],
edge_points[4][0],edge_points[4][1]);
Line(edge_points[2][0],edge_points[2][1],
edge_points[4][0],edge_points[4][1]);
Line(edge_points[3][0],edge_points[3][1],
edge_points[4][0],edge_points[4][1]);
}
/************************************************************************///--------------------- get_projected_point( ) -----------------------///************************************************************************/void get_projected_point(int& x,int& y,int& z)
{
float d0=((n1*x0)+(n2*y0)+(n3*z0));
float d1=((n1*a)+(n2*b)+(n3*c));
float d=(d0-d1);
float Per_NRC[4][4]={
{(d-(a*n1)),(b*n1),(c*n1),n1},
{(a*n2),(d+n2*b),(c*n2),n2},
{(a*n3),(b*n3),(d+(c*n3)),n3},
{(-a*d0),(-b*d0),(-c*d0),-d1}
};
float xy[4]={x,y,z,1};
float new_xy[4]={0};
multiply_matrices(xy,Per_NRC,new_xy);
x=(int)(new_xy[0]+0.5);
y=(int)(new_xy[1]+0.5);
z=(int)(new_xy[2]+0.5);
}
/************************************************************************///---------------------- multiply_matrices( ) ------------------------///************************************************************************/void multiply_matrices(constfloat matrix_1[4],
constfloat matrix_2[4][4],float matrix_3[4])
{
for(int count_1=0;count_1<4;count_1++)
{
for(int count_2=0;count_2<4;count_2++)
matrix_3[count_1]+=
(matrix_1[count_2]*matrix_2[count_2][count_1]);
}
}
/*************************************************************************///-------------------------- Line( ) ------------------------///*************************************************************************/void Line(constint x_1,constint y_1,constint x_2,constint y_2)
{
int color=getcolor( );
int x1=x_1;
int y1=y_1;
int x2=x_2;
int y2=y_2;
if(x_1>x_2)
{
x1=x_2;
y1=y_2;
x2=x_1;
y2=y_1;
}
int dx=abs(x2-x1);
int dy=abs(y2-y1);
int inc_dec=((y2>=y1)?1:-1);
if(dx>dy)
{
int two_dy=(2*dy);
int two_dy_dx=(2*(dy-dx));
int p=((2*dy)-dx);
int x=x1;
int y=y1;
putpixel(x,y,color);
while(x<x2)
{
x++;
if(p<0)
p+=two_dy;
else
{
y+=inc_dec;
p+=two_dy_dx;
}
putpixel(x,y,color);
}
}
else
{
int two_dx=(2*dx);
int two_dx_dy=(2*(dx-dy));
int p=((2*dx)-dy);
int x=x1;
int y=y1;
putpixel(x,y,color);
while(y!=y2)
{
y+=inc_dec;
if(p<0)
p+=two_dx;
else
{
x++;
p+=two_dx_dy;
}
putpixel(x,y,color);
}
}
}
/*************************************************************************///-------------------------- show_screen( ) ---------------------------///*************************************************************************/void show_screen( )
{
setfillstyle(1,1);
bar(182,26,438,38);
settextstyle(0,0,1);
setcolor(15);
outtextxy(5,5,"******************************************************************************");
outtextxy(5,17,"*-**************************************************************************-*");
outtextxy(5,29,"*-------------------- ----------------------*");
outtextxy(5,41,"*-**************************************************************************-*");
outtextxy(5,53,"*-**************************************************************************-*");
setcolor(11);
outtextxy(189,29,"General Perspective Projection");
setcolor(15);
for(int count=0;count<=30;count++)
outtextxy(5,(65+(count*12)),"*-* *-*");
outtextxy(5,438,"*-**************************************************************************-*");
outtextxy(5,450,"*--------------------------- ------------------------*");
outtextxy(5,462,"******************************************************************************");
setcolor(12);
outtextxy(227,450," Press any key to exit ");
}