The document describes a program for detecting collisions between 2D objects using the min-max test or bounding box test. The min-max test detects collisions by comparing the minimum and maximum x and y coordinates of two objects' bounding boxes. If the minimum x of one object is greater than the maximum x of the other (or vice versa for y), no collision is possible. The C code provided implements these collision detection algorithms by finding the min-max coordinates of rectangles and testing if a moving line intersects any rectangles.

1. Practical No. 5
TITLE: Collision Detection
AIM: Detecting a Collision of 2 2D-objects based on Min-max test or Bounding Box test.
DESCRIPTION:
● Collision detection between 2D objects is effected by comparing the minimum-maximum
x- and y- events for two shapes/objects.
● Min-Max Test:
If A and B are 2 objects having extends(x-mina, x-maxa, y-mina, y-maxa)
(x-minb, x-maxb, y-minb, y-maxb) then a horizontal overlap or touch condition is
impossible if:
x-minb > x-maxa OR x-mina > x-maxb.
Similarly vertical overlap or touch condition is impossible if:
y-minb > y-maxa OR y-mina > y-maxb.
SOURCE CODE:
/*Collision Detection*/
#include<graphics.h>
#include<stdio.h>

2. #include<conio.h>
#include<dos.h>
#include<math.h>
int lx,ly,lx1,ly1,l1_x,l1_y,l2_x,l2_y,l3_x,l3_y;
int l1_x1,l1_y1,l2_x1,l2_y1,l3_x1,l3_y1;
int l4_x,l4_y,l4_x1,l4_y1,maxx,maxy,minx,miny;
float x,y,m,x3,y3;
int getmax_x(int,int,int,int);
int getmax_y(int,int,int,int);
int getmin_x(int,int,int,int);
int getmin_y(int,int,int,int);
int collision(int,int,int,int,int,int);
void draw_rectangle();
void main()
{
int i,ch=32,co;
int gm,gd=DETECT;
//clrscr();
initgraph(&gd,&gm,"C:TCBGI");
draw_rectangle();
printf("nInput line coordinatesn");
scanf("%d %d %d %d",&l4_x,&l4_y,&l4_x1,&l4_y1);
maxx=getmax_x(lx,l1_x,l2_x,l3_x);
maxy=getmax_y(ly,l1_y,l2_y,l3_y);
minx=getmin_x(lx1,l1_x1,l2_x1,l3_x1);
miny=getmin_y(ly1,l1_y1,l2_y1,l3_y1);
line(l4_x,l4_y,l4_x1,l4_y1);
//moveto(500,500);
//printf("maxx=%dn maxy=%3dn minx=%4dn miny=%6dn",maxx,maxy,minx,miny);
while(ch==32)
{
if(l4_x==l4_x1)
{
cleardevice();
draw_rectangle();
l4_y1=l4_y1+5;
l4_y=l4_y+5;

3. }
else
{
if(l4_y==l4_y1)
{
cleardevice();
draw_rectangle();
l4_x1=l4_x1+5;
l4_x=l4_x+5;
}
}
co=collision(l4_x1,l4_y1,maxx,maxy,minx,miny);
if(co==0)
{
line(l4_x,l4_y,l4_x1,l4_y1);
}
ch=getche();
}
getch();
closegraph();
}
void draw_rectangle()
{
lx=230;ly=150;lx1=330;ly1=150;
l1_x=230;l1_y=150;l1_x1=230;l1_y1=250;
l2_x=230;l2_y=250;l2_x1=330;l2_y1=250;
l3_x=330;l3_y=150;l3_x1=330;l3_y1=250;
line(lx,ly,lx1,ly1);
line(l1_x,l1_y,l1_x1,l1_y1);
line(l2_x,l2_y,l2_x1,l2_y1);
line(l3_x,l3_y,l3_x1,l3_y1);
}
int getmax_x(int x1,int x2,int x3,int x4)
{
if(x1>x2 && x1>x3 && x1>x4)
{
return x1;
}
else
{

4. if(x2>x1 && x2>x3 && x2>x4)
{
return x2;
}
else
{
if(x3>x1 && x3>x2 && x3>x4)
{
return x3;
}
else if(x4>x1 && x4>x2 && x4>x3)
{
return x4;
}
}
}
return 0;
}
int getmax_y(int y1,int y2,int y3,int y4)
{
if(y1>y2 && y1>y3 && y1>y4)
{
return y1;
}
else
{
if(y2>y1 && y2>y3 && y2>y4)
{
return y2;
}
else
{
if(y3>y1 && y3>y2 && y3>y4)
{
return y3;
}
else if(y4>y1 && y4>y2 && y4>y3)
{
return y4;
}

5. }
}
return 0;
}
int getmin_x(int xx1,int xx2,int xx3,int xx4)
{
if(xx1<xx2 && xx1<xx3 && xx1<xx4)
{
return xx1;
}
else
{
if(xx2<xx1 && xx2<xx3 && xx2<xx4)
{
return xx2;
}
else
{
if(xx3<xx1 && xx3<xx2 && xx3<xx4)
{
return xx3;
}
else if(xx4<xx1 && xx4<xx2 && xx4<xx3)
{
return xx4;
}
}
}
return 0;
}
int getmin_y(int yy1,int yy2,int yy3,int yy4)
{
if(yy1<yy2 && yy1<yy3 && yy1<yy4)
{
return yy1;
}
else
{
if(yy2<yy1 && yy2<yy3 && yy2<yy4)

6. {
return yy2;
}
else
{
if(yy3<yy1 && yy3<yy2 && yy3<yy4)
{
return yy3;
}
else if(yy4<yy1 && yy4<yy2 && yy4<yy3)
{
return yy4;
}
}
}
return 0;
}
int collision(int x,int y,int maxx,int maxy,int minx,int miny)
{
if((x>=minx && x<=maxx) && (y>=miny && y<=maxy))
{
moveto(20,20);
printf("collision detected");
return 1;
}
return 0;
}

7. OUTPUT: