Help with Galaxian.

This is a discussion on Help with Galaxian. within the Game Programming forums, part of the General Programming Boards category; I am currently programming a version of Galaxian as part of a HNC course I am doing, the problem is ...

  1. #1
    Registered User
    Join Date
    Jan 2005
    Posts
    3

    Help with Galaxian.

    I am currently programming a version of Galaxian as part of a HNC course I am doing, the problem is with getting my arrays working (the first 10x3 aliens are working fine, it's just the next two alien lines). Here is the code:
    globals.cpp
    ENEMY Enemies[10][3]; (this one is working)
    ENEMY2 Enemies2[10][1]; (this is the one that is not)

    globals.h has the same two lines

    Game_loop
    void Initialise()
    {
    int xpos,ypos,xsub,ysub;

    Draw_Ship();

    for (xpos=100, xsub=0; xpos<=640; xpos+=60, xsub++)
    {
    for (ypos=280, ysub=0; ypos<=400; ypos+=60, ysub++)
    {
    Enemies[xsub][ysub].x=xpos;
    Enemies[xsub][ysub].y=ypos;
    Enemies[xsub][ysub].alive=1;
    Draw_Enemies(xpos,ypos);
    }
    }

    starttime=GetTickCount();

    for (xpos=100, xsub=0; xpos<=640; xpos+=60, xsub++)
    {
    for (ypos=460, ysub=0; ypos<=520; ypos+=60, ysub++)
    {
    Enemies[xsub][ysub].x=xpos;
    Enemies[xsub][ysub].y=ypos;
    Enemies[xsub][ysub].alive=1;
    Draw_Enemies2(xpos,ypos);
    }
    }

    Any help will GREATLY appreciated. Thanks.

  2. #2
    S Sang-drax's Avatar
    Join Date
    May 2002
    Location
    Göteborg, Sweden
    Posts
    2,072
    Please enclose your code with [CODE] and [/CODE].
    Last edited by Sang-drax : Tomorrow at 02:21 AM. Reason: Time travelling

  3. #3
    and the hat of wrongness Salem's Avatar
    Join Date
    Aug 2001
    Location
    The edge of the known universe
    Posts
    32,422
    Well you don't use Enemies2 in your 2nd set of loops.

    Even if you did, for (ypos=460, ysub=0; ypos<=520; ypos+=60, ysub++) loops twice, so on the 2nd iteration, you would be accessing out of bounds.

    It might be a good idea to check your other cases as well, to make sure they're not off-by-1 as well.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  4. #4
    Registered User
    Join Date
    Jan 2005
    Posts
    3
    Green=Game Loop Red=Globals.cpp Blue=Globals.h
    Code:
    #include "Globals.h"
    
    void Main_Loop()
    {
    	
    	if (KEYDOWN(VK_ESCAPE))
    	{		
    	    SendMessage(GameHandle, WM_CLOSE, 0,0);		
    	}
    
    	weaponendtime=(GetTickCount()-weaponstarttime);
    	if ((int)weaponendtime>weaponspeed)
    	{
    		if (KEYDOWN(VK_RIGHT))
    		{
    			if (ShipX<757)
    			{
    				Clear_Ship();
    				ShipX+=5;
    				Draw_Ship();
    				//Sleep(1);
    			}
    		}
    
    		if (KEYDOWN(VK_LEFT))
    		{
    			if (ShipX>3)
    			{
    				Clear_Ship();
    				ShipX-=5;
    				Draw_Ship();
    				//Sleep(1);
    			}
    		}
    		weaponstarttime=GetTickCount();
    	}
    
    	endtime=(GetTickCount()-starttime);
    	if ((int)endtime>movespeed)
    	{
    		Move_Enemies();
    		starttime=GetTickCount();
    	}
    }
    
    void Initialise()
    {
    	int xpos,ypos,xsub,ysub;
    
    	Draw_Ship();
    
    	for (xpos=100, xsub=0; xpos<=640; xpos+=60, xsub++)
    	{
    		for (ypos=280, ysub=0; ypos<=400; ypos+=60, ysub++)
    		{
    			Enemies[xsub][ysub].x=xpos;
    			Enemies[xsub][ysub].y=ypos;
    			Enemies[xsub][ysub].alive=1;
    			Draw_Enemies(xpos,ypos);
    		}
    	}
    
    	starttime=GetTickCount();
    
    	for (xpos=100, xsub=0; xpos<=640; xpos+=60, xsub++)
    	{
    		for (ypos=460, ysub=0; ypos<=520; ypos+=60, ysub++)
    		{
    			Enemies2[xsub][ysub].x=xpos;
    			Enemies2[xsub][ysub].y=ypos;
    			Enemies2[xsub][ysub].alive=1;
    			Draw_Enemies2(xpos,ypos);
    		}
    	}
    
    	/*for (xpos=260; xpos<=530; xpos+=30)
    	{
    		for (ypos=116; ypos<=148; ypos+=30)
    		{
    			Draw_Enemies3(xpos,ypos);
    		}
    	}*/
    
    }
    
    
    void Draw_Ship()
    {
    	HDC hdc;
    	HBRUSH hbrush;
    
    	hdc = GetDC(GameHandle);
    
    	RECT rect; // used to hold rect info
    
    	hbrush = CreateSolidBrush(RGB(255,0,0));
    
    	rect.left   = ShipX+13;
    	rect.top    = ShipY+3;
    	rect.right  = ShipX+26;
    	rect.bottom = ShipY+26;
    	FillRect(hdc,&rect,hbrush);
    	DeleteObject(hbrush);
    
    	hbrush = CreateSolidBrush(RGB(0,0,255));
    	rect.left   = ShipX+3;
    	rect.top    = ShipY+10;
    	rect.right  = ShipX+13;
    	rect.bottom = ShipY+16;
    	FillRect(hdc,&rect,hbrush);
    	DeleteObject(hbrush);
    
    	hbrush = CreateSolidBrush(RGB(0,0,255));
    	rect.left   = ShipX+26;
    	rect.top    = ShipY+10;
    	rect.right  = ShipX+36;
    	rect.bottom = ShipY+16;
    	FillRect(hdc,&rect,hbrush);
    	DeleteObject(hbrush);
    
    	hbrush = CreateSolidBrush(RGB(0,255,0));
    	rect.left   = ShipX-1;
    	rect.top    = ShipY+5;
    	rect.right  = ShipX+3;
    	rect.bottom = ShipY+22;
    	FillRect(hdc,&rect,hbrush);
    	DeleteObject(hbrush);
    
    	hbrush = CreateSolidBrush(RGB(0,255,0));
    	rect.left   = ShipX+36;
    	rect.top    = ShipY+5;
    	rect.right  = ShipX+40;
    	rect.bottom = ShipY+22;
    	FillRect(hdc,&rect,hbrush);
    	DeleteObject(hbrush);
    
    	hbrush = CreateSolidBrush(RGB(255,255,0));
    	rect.left   = ShipX+16;
    	rect.top    = ShipY;
    	rect.right  = ShipX+23;
    	rect.bottom = ShipY+3;
    	FillRect(hdc,&rect,hbrush);
    	DeleteObject(hbrush);
    
    	ReleaseDC(GameHandle,hdc);
    }
    
    void Clear_Ship()
    {
    	RECT BlankRect; // used to write a blank
    
    	HDC hdc;
    	HBRUSH hbrush;
    
    	hdc = GetDC(GameHandle);
    
    	hbrush = CreateSolidBrush(RGB(0,0,0));
    
    	BlankRect.left		= ShipX-5;
    	BlankRect.top		= ShipY;
    	BlankRect.right		= ShipX+40;
    	BlankRect.bottom	= ShipY+26;
    	FillRect(hdc,&BlankRect,hbrush);
    }
    
    void Draw_Enemies(int x, int y)
    {
    	HDC hdc;
    	HBRUSH hbrush;
    
    	hdc = GetDC(GameHandle);
    
    	RECT rect; // used to hold rect info
    
    	hbrush = CreateSolidBrush(RGB(0,100,255));
    
    	rect.left   = x+5;
    	rect.top    = y+3;
    	rect.right  = x+25;
    	rect.bottom = y+20;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x+7;
    	rect.top    = y+20;
    	rect.right  = x+23;
    	rect.bottom = y+25;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x;
    	rect.top    = y+5;
    	rect.right  = x+5;
    	rect.bottom = y+7;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x+25;
    	rect.top    = y+5;
    	rect.right  = x+30;
    	rect.bottom = y+7;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x;
    	rect.top    = y;
    	rect.right  = x+2;
    	rect.bottom = y+5;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x+28;
    	rect.top    = y;
    	rect.right  = x+30;
    	rect.bottom = y+5;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x+12;
    	rect.top    = y+25;
    	rect.right  = x+18;
    	rect.bottom = y+30;
    	FillRect(hdc,&rect,hbrush);
    
    	
    	DeleteObject(hbrush);
    
    	hbrush = CreateSolidBrush(RGB(255,255,255));
    	rect.left   = x+8;
    	rect.top    = y+7;
    	rect.right  = x+12;
    	rect.bottom = y+10;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x+18;
    	rect.top    = y+7;
    	rect.right  = x+22;
    	rect.bottom = y+10;
    	FillRect(hdc,&rect,hbrush);
    
    	DeleteObject(hbrush);
    
    	ReleaseDC(GameHandle,hdc);
    
    	
    }
    
    
    void Draw_Enemies2(int x, int y)
    {
    	HDC hdc;
    	HBRUSH hbrush;
    
    	hdc = GetDC(GameHandle);
    
    	RECT rect; // used to hold rect info
    
    	hbrush = CreateSolidBrush(RGB(255,0,50));
    
    	rect.left   = x+5;
    	rect.top    = y+3;
    	rect.right  = x+25;
    	rect.bottom = y+20;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x+7;
    	rect.top    = y+20;
    	rect.right  = x+23;
    	rect.bottom = y+25;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x;
    	rect.top    = y+5;
    	rect.right  = x+5;
    	rect.bottom = y+7;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x+25;
    	rect.top    = y+5;
    	rect.right  = x+30;
    	rect.bottom = y+7;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x;
    	rect.top    = y;
    	rect.right  = x+2;
    	rect.bottom = y+5;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x+28;
    	rect.top    = y;
    	rect.right  = x+30;
    	rect.bottom = y+5;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x+12;
    	rect.top    = y+25;
    	rect.right  = x+18;
    	rect.bottom = y+30;
    	FillRect(hdc,&rect,hbrush);
    
    	
    	DeleteObject(hbrush);
    
    	hbrush = CreateSolidBrush(RGB(255,255,255));
    	rect.left   = x+8;
    	rect.top    = y+7;
    	rect.right  = x+12;
    	rect.bottom = y+10;
    	FillRect(hdc,&rect,hbrush);
    
    	rect.left   = x+18;
    	rect.top    = y+7;
    	rect.right  = x+22;
    	rect.bottom = y+10;
    	FillRect(hdc,&rect,hbrush);
    
    	DeleteObject(hbrush);
    
    	ReleaseDC(GameHandle,hdc);
    }
    
    /*void Draw_Enemies3(int x, int y)
    {
    	HDC hdc;
    	HBRUSH hbrush;
    	
    	hdc = GetDC(GameHandle);
    
    	hbrush = CreateSolidBrush (RGB(0,200,0));
    	SelectObject(hdc,hbrush);
    
    	int num_points=11;
    	POINT point_list[11];
    
    	point_list[0].x=x;
    	point_list[0].y=y+2;
    	point_list[1].x=x+5;
    	point_list[1].y=y+2;
    	point_list[2].x=x+5;
    	point_list[2].y=y;
    	point_list[3].x=x+7;
    	point_list[3].y=y;
    	point_list[4].x=x+7;
    	point_list[4].y=y+2;
    	point_list[5].x=x+13;
    	point_list[5].y=y+2;
    	point_list[6].x=x+13;
    	point_list[6].y=y;
    	point_list[7].x=x+15;
    	point_list[7].y=y;
    	point_list[8].x=x+15;
    	point_list[8].y=y+2;
    	point_list[9].x=x+20;
    	point_list[9].y=y+2;
    	point_list[10].x=x+10;
    	point_list[10].y=y+22;
    
    
    	Polygon(hdc,point_list,num_points); //Main body of the enemies
    	DeleteObject(hbrush);
    }*/
    
    void Clear_Enemies(int x, int y)
    {
    	RECT BlankRect; //used to write a blank
    
    	HDC hdc;
    	HBRUSH hbrush;
    
    	hdc = GetDC(GameHandle);
    
    	hbrush = CreateSolidBrush(RGB(0,0,0));
    
    	BlankRect.left		= x;
    	BlankRect.top		= y;
    	BlankRect.right		= x+30;
    	BlankRect.bottom	= y+30;
    	FillRect(hdc,&BlankRect,hbrush);
    
    	DeleteObject(hbrush);
    	ReleaseDC(GameHandle,hdc);
    }
    
    void Move_Enemies()
    {
    	HDC hdc;
    	hdc = GetDC(GameHandle);
    
    	if (direction=='L')
    	{
    		trackx-=pixelmove;
    	}
    	else
    	{
    		trackx+=pixelmove;
    	}
    	for (int enemyx=0; enemyx<10; enemyx++)
    	{
    		for (int enemyy=0; enemyy<5; enemyy++)
    		{
    			if (Enemies[enemyx][enemyy].alive==1)
    			{
    				Clear_Enemies(Enemies[enemyx][enemyy].x,
    					Enemies[enemyx][enemyy].y);
    				if (direction=='L')
    				{
    					Enemies[enemyx][enemyy].x-=pixelmove;
    				}
    				else
    				{
    					Enemies[enemyx][enemyy].x+=pixelmove;
    				}
    				Draw_Enemies(Enemies[enemyx][enemyy].x, Enemies[enemyx][enemyy].y);
    			}
    		}
    	}
    
    	if (direction=='L')
    	{
    		for (int pos=100; pos<600; pos++)
    		{
    			if (GetPixel(hdc,5,pos)==RGB(255,0,0))
    			{
    				direction='R';
    			}
    		}
    	}
    		
    
    	if (direction=='R')
    	{
    		for (int pos=100; pos<600; pos++)
    		{
    			if (GetPixel(hdc,790,pos)==RGB(255,0,0))
    			{
    				direction='L';
    			}
    		}
    	}
    	ReleaseDC(GameHandle,hdc);
    }
    
    #include "Globals.h"
    
    HWND GameHandle;
    int ShipX=380, ShipY=570;
    int weaponspeed=1;
    int enemyx=50, enemyy=250;
    int movespeed=300, trackx=50, tracky=250, pixelmove=6;
    char direction='L';
    
    ENEMY Enemies[10][3];
    ENEMY2 Enemies2[10][1];
    
    DWORD weaponstarttime, weaponendtime;
    DWORD starttime, endtime;
    
    
    #pragma once
    
    #define WIN32_LEAN_AND_MEAN  // Compile only necessary elements
    
    #include <windows.h>   // include all the windows headers
    #include <stdlib.h>
    #include <stdio.h>
    
    // defines for windows 
    #define WINDOW_CLASS_NAME "WINCLASS1"
    #define TITLE "Space_Engagement"
    #define WINDOW_WIDTH  808 // Need these settings to give 800x600 ex border
    #define WINDOW_HEIGHT 634
    
    // Macros
    
    #define KEYDOWN(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 1 : 0)
    #define KEYUP(vk_code)   ((GetAsyncKeyState(vk_code) & 0x8000) ? 0 : 1)
    
    // Structures
    struct ENEMY
    {
    	int x;
    	int y;
    	int alive; // 1=alive, 0=dead;
    }
    ;
    
    extern ENEMY Enemies[10][3];
    extern ENEMY2 Enemies2[10][1];
    
    //Globals
    extern int ShipX, ShipY;
    extern HWND GameHandle;
    extern DWORD weaponstarttime, weaponendtime;
    extern int weaponspeed;
    extern int enemyx, enemyy;
    extern DWORD endtime, starttime;
    
    
    // Function Prototypes ////////////////////////////////
    
    void Main_Loop();
    void Draw_Ship();
    void Initialise();
    void Clear_Ship();
    void Draw_Enemies(int x, int y);
    void Draw_Enemies2(int x, int y);
    /*void Draw_Enemies3(int x, int y);*/
    void Clear_Enemies(int x, int y);
    extern int movespeed, trackx, tracky, pixelmove;
    extern char direction;
    void Move_Enemies();
    
    
    Can anyone see where I am going wrong?

  5. #5
    Registered User
    Join Date
    Jan 2005
    Posts
    3
    no odds now, the deadline has come and gone. I just went for a 10x5 layout but I had other problems too. I could not get the attacks right (where they leave and re-enter the screen unless blown away or if they have collided with the ship) I also had problems with getting the enemies to fire and getting a score to calculate and print out on screen. Any Ideas as it could be useful for future refernce.

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Galaxian or Space invaders for my next game (read this)
    By Leeman_s in forum C++ Programming
    Replies: 7
    Last Post: 11-07-2001, 08:28 PM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21