# include <iostream.h>
# include <graphics.h>
# include <conio.h>
# include <math.h>
# define f 0.3
# define projection_angle 45
void show_screen( );
void apply_rotation_along_y_axis(constint [5][3],constint);
void multiply_matrices(constfloat[4],constfloat[4][4],float[4]);
void draw_pyramid(int [5][3]);
void get_projected_point(int&,int&,int&);
void Line(constint,constint,constint,constint);
int main( )
{
int driver=VGA;
int mode=VGAHI;
initgraph(&driver,&mode,"..\\Bgi");
show_screen( );
int pyramid[5][3]={
{70,300,50}, // base front left
{170,300,50}, // base front right
{170,300,-50}, // base back right
{70,300,-50}, // base back left
{120,150,0} // top
};
setcolor(15);
draw_pyramid(pyramid);
setcolor(15);
settextstyle(0,0,1);
outtextxy(50,415,"*** Use + & - Keys to apply Rotation along y-axis.");
int angle=0;
int key_code=0;
char Key=NULL;
do
{
Key=NULL;
key_code=0;
Key=getch( );
key_code=int(Key);
if(key_code==0)
{
Key=getch( );
key_code=int(Key);
}
if(key_code==27)
break;
elseif(key_code==43)
angle-=5;
elseif(key_code==45)
angle+=5;
setfillstyle(1,0);
bar(40,70,600,410);
apply_rotation_along_y_axis(pyramid,angle);
}
while(1);
return 0;
}
/*************************************************************************///------------------- apply_rotation_along_y_axis( ) ------------------///*************************************************************************/void apply_rotation_along_y_axis(constint control_points[5][3],
constint theta)
{
int edge_points[5][3]={0};
float angle=(theta*(M_PI/180));
for(int count=0;count<5;count++)
{
edge_points[count][0]=control_points[count][0];
edge_points[count][1]=control_points[count][1];
edge_points[count][2]=control_points[count][2];
float matrix_a[4]={edge_points[count][0],edge_points[count][1],
edge_points[count][2],1};
float matrix_b[4][4]={
{ cos(angle),0,-sin(angle),0 } ,
{ 0,1,0,0 } ,
{ sin(angle),0,cos(angle),0 } ,
{ 0,0,0,1 }
};
float matrix_c[4]={0};
multiply_matrices(matrix_a,matrix_b,matrix_c);
edge_points[count][0]=(int)(matrix_c[0]+0.5);
edge_points[count][1]=(int)(matrix_c[1]+0.5);
edge_points[count][2]=(int)(matrix_c[2]+0.5);
}
setcolor(10);
draw_pyramid(edge_points);
}
/************************************************************************///---------------------- 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]);
}
}
/************************************************************************///-------------------------- draw_pyramid( ) -------------------------///************************************************************************/void draw_pyramid(int points[5][3])
{
int edge_points[5][3];
for(int i=0;i<5;i++)
{
edge_points[i][0]=points[i][0];
edge_points[i][1]=points[i][1];
edge_points[i][2]=points[i][2];
get_projected_point(edge_points[i][0],
edge_points[i][1],edge_points[i][2]);
edge_points[i][0]+=320;
}
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 fcos0=(f*cos(projection_angle*(M_PI/180)));
float fsin0=(f*sin(projection_angle*(M_PI/180)));
float Par_v[4][4]={
{1,0,0,0},
{0,1,0,0},
{fcos0,fsin0,0,0},
{0,0,0,1}
};
float xy[4]={x,y,z,1};
float new_xy[4]={0};
multiply_matrices(xy,Par_v,new_xy);
x=(int)(new_xy[0]+0.5);
y=(int)(new_xy[1]+0.5);
z=(int)(new_xy[2]+0.5);
}
/*************************************************************************///------------------------------- 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(210,26,420,38);
settextstyle(0,0,1);
setcolor(15);
outtextxy(5,5,"******************************************************************************");
outtextxy(5,17,"*-**************************************************************************-*");
outtextxy(5,29,"*----------------------- ------------------------*");
outtextxy(5,41,"*-**************************************************************************-*");
outtextxy(5,53,"*-**************************************************************************-*");
setcolor(11);
outtextxy(218,29,"3D Rotation along Y-axis");
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(229,450,"Press any Key to exit.");
}