Thread: How to stop an object from walking through a wall?

Hi,

I'm try to make a small code that when the object moves into a wall it won't move anymore

My code is

Code:

#include <stdio.h>
#include <windows.h>
#include <stdlib.h> //To clear the screen
void drawplayer(int x, int y, WORD color)
{
	HANDLE Poutputh;
	COORD Ppos = {x,y};
	Poutputh = GetStdHandle(STD_OUTPUT_HANDLE);
	SetConsoleTextAttribute(Poutputh, color);
	SetConsoleCursorPosition(Poutputh, Ppos);
}

int drawblocks(int bx, int by, WORD bcolor)
{
	HANDLE boutput;
	COORD bpos = {bx,by};
	boutput = GetStdHandle(STD_OUTPUT_HANDLE);
	SetConsoleTextAttribute(boutput, bcolor);
	SetConsoleCursorPosition(boutput, bpos);
}

x = 7;
y = 8;
int KeyR = 0;
int KeyR2 = 0;
int KeyR3 = 0;
int KeyR4 = 0;
int play = 1;
int c = 0;
int KeyPress(int key)
{
	return GetAsyncKeyState(key);
}

int main()
{
	{
	while(play == 1)
	{
	c = 0;
	drawplayer(x, y, FOREGROUND_RED);
	printf("@");
	drawblocks(9, 2, FOREGROUND_GREEN | FOREGROUND_INTENSITY);
	printf("#");

	if(KeyPress(VK_UP))
	{
		if(KeyR == 0)
		{
			if(y > 0)
			{
			system ("cls");
			y = y - 1;
			KeyR = 1;
			}
		}
	}
	if(!KeyPress(VK_UP))
	{
		if(KeyR == 1)
		{
			KeyR = 0;
		}
	}
	
	if(KeyPress(VK_RIGHT))
	{
		if(KeyR2 == 0)
		{
			if(x < 79)
			{
			system ("cls");
			x = x + 1;
			KeyR2 = 1;
			}
		}
	}
	
	if(!KeyPress(VK_RIGHT))
	{
		if(KeyR2 == 1)
		{
			KeyR2 = 0;
		}
	}

	if(KeyPress(VK_LEFT))
	{
		if(KeyR3 == 0)
		{
			if(x > 0)
			{
				system ("cls");
				x = x -1;
				KeyR3 = 1;
			}
		}
	}

	if(!KeyPress(VK_LEFT))
	{
		if(KeyR3 == 1)
		{
			KeyR3 = 0;
		}
			if(y < 24)
			{
				system ("cls");
	}

	if(KeyPress(VK_DOWN))
	{
		if(KeyR4 == 0)
		{
				y = y + 1;
				KeyR4 = 1;
			}
		}
	}

	if(!KeyPress(VK_DOWN))
	{
		if(KeyR4 == 1)
		{
			KeyR4 = 0;
		}
	}

}
}
}

Well first I would recommend you to use OpenGL for such things, well about the question it self, you can imagine your object is inside a box/sphere so you can check its lengh/2 or radius and see if it touches the wall. I got a function that stops an air plane to cross the floor on a opengl project I can post if you wanna check but the basic idea is you need to define a plane and check collision against it.

My program runs in dos, I don't think you can run OPENGL in Dos.

> if(!KeyPress(VK_LEFT))
After this point, the braces and indentation are all wrong.

Originally Posted by Salem

> if(!KeyPress(VK_LEFT))
After this point, the braces and indentation are all wrong.

Yes I know, that's what stops my object from moving when a key is pressed, but I'm trying to figure out how to stop my object from going through a wall in my program.

Better use of conditions like
if(y < 24)
would seem to be the way to go.

Or you could have a map of the screen, say
char map[80][24];

And tests like
if ( map[x][y+1] != '#' ) y = y + 1;

That is, you only move to a position if there is no wall there.
Extend this idea to cover other things you can't move into, say monsters, or things you can pick up, say food.