Programming Forums > Application Development > C++

Wizard1988 · Jul 1st, 2006, 6:18 PM

I am attempting to write a side scroller using SDL. First I am experimenting with creating a map using two dimensional arrays. The array I am currently using is an integer array or 5 by 10. Value of 0 means that it represents the sky, 1 represents grass, and 2 represents dirt.

Here is how the array looks:

(Toggle Plain Text)

{
{0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0},
{1,1,1,1,1,1,1,1,1,1},
{2,2,2,2,2,2,2,2,2,2}	
		};

The problem:

Somewhere in my code is a bug which throws off the position of the
tiles :mad:

The grass should be flat across the whole thing.

Here is my code:

(Toggle Plain Text)

#include <SDL.h>
#include <iostream>

const int TILESIZE = 32;
const int LEVELHEIGHT = 15;
const int LEVELWIDTH = 100;

const int SKY = 0;
const int GRASS = 1;
const int DIRT = 2;

SDL_Surface* screen;
SDL_Surface* sky;
SDL_Surface* grass;
SDL_Surface* dirt;

SDL_Event event;

int map [10][5];


class Tile
{
private:
	int type;
	bool solid;
	SDL_Surface* image;
	SDL_Rect box;
public:
	Tile(int x, int y, bool s, int t, SDL_Surface* img);
	SDL_Surface* getImg(){return image;}
	SDL_Rect getBox(){return box;}
	bool IsSolid(){return solid;}
};

Tile::Tile(int x, int y, bool s, int t, SDL_Surface* img)
{
	box.x = x;
	box.y = y;
	box.w = TILESIZE;
	box.h = TILESIZE;
	solid = s;
	type = t;
	image = img;
}


void MakeMap()
{
	for(int y = 0; y<5;y++)
	{
		for(int x = 0; x<10;x++)
		{
			if(y <=2)
			{
				map[y][x] = 0;
			}
			if(y == 3)
			{
				map[y][x] = 1;
			}
			if(y == 4)
			{
				map[y][x] = 2;
			}
		}
	}
}

bool init()
{
	if(SDL_Init(SDL_INIT_EVERYTHING) == -1 )
	{
		return false;
	}

	screen = SDL_SetVideoMode(640,480,32,SDL_SWSURFACE);

	atexit(SDL_Quit);
	return true;
}

SDL_Surface* LoadBitmap( std::string filename ) 
{
    SDL_Surface* loadedImage = NULL;
    SDL_Surface* optimizedImage = NULL;

	loadedImage = SDL_LoadBMP(filename.c_str());
    
    if( loadedImage != NULL )
    {
        optimizedImage = SDL_DisplayFormat( loadedImage );
        SDL_FreeSurface( loadedImage );
    }

    return optimizedImage;
}




void ApplySurface(int x, int y, SDL_Surface* source, SDL_Surface* destination,SDL_Rect* clip = NULL)
{
	SDL_Rect offset;
    offset.x = x;
    offset.y = y;
    SDL_BlitSurface( source, clip, destination, &offset );
}

void LoadMap(Tile* TileM[5][10])
{
	for(int y = 0; y<5;y++)
	{
		for(int x= 0; x<10;x++)
		{
			switch(map[y][x])
			{
			case 0:
				TileM[y][x] = new Tile(x*TILESIZE,y*TILESIZE,false,0,sky);
				break;
			case 1:
				TileM[y][x] = new Tile(x*TILESIZE,y*TILESIZE,true,1,grass);
				break;
			case 2:
				TileM[y][x] = new Tile(x*TILESIZE,y*TILESIZE,true,2,dirt);
				break;
			}
		}
	}
}

void DrawMap(Tile* TileM[5][10])
{
	for(int y = 0; y<5; y++)
	{
		for(int x = 0; x<10; x++)
		{
			ApplySurface(TileM[y][x]->getBox().x,TileM[y][x]->getBox().y,TileM[y][x]->getImg(),screen);
		}
	}
}

int main(int argc, char** args)
{
	bool quit = false;
	Tile* TileMap[5][10];

	if(!init())
	{
		return  1;
	}

	dirt = LoadBitmap("C:/Dirt.bmp");
	grass = LoadBitmap("C:/Grass.bmp");
	sky = LoadBitmap("C:/Sky.bmp");

	MakeMap();
	LoadMap(TileMap);
	
	while(!quit)
	{
		
		while(SDL_PollEvent(&event ))
        {
            if( event.type == SDL_QUIT )
            {
                quit = true;
            }
        }
		DrawMap(TileMap);
		if( SDL_Flip( screen ) == -1 )
        {
            return 2;    
        }
		
	}
	return 0;
}

#include <SDL.h>
#include <iostream>

const int TILESIZE = 32;
const int LEVELHEIGHT = 15;
const int LEVELWIDTH = 100;

const int SKY = 0;
const int GRASS = 1;
const int DIRT = 2;

SDL_Surface* screen;
SDL_Surface* sky;
SDL_Surface* grass;
SDL_Surface* dirt;

SDL_Event event;

int map [10][5];


class Tile
{
private:
	int type;
	bool solid;
	SDL_Surface* image;
	SDL_Rect box;
public:
	Tile(int x, int y, bool s, int t, SDL_Surface* img);
	SDL_Surface* getImg(){return image;}
	SDL_Rect getBox(){return box;}
	bool IsSolid(){return solid;}
};

Tile::Tile(int x, int y, bool s, int t, SDL_Surface* img)
{
	box.x = x;
	box.y = y;
	box.w = TILESIZE;
	box.h = TILESIZE;
	solid = s;
	type = t;
	image = img;
}


void MakeMap()
{
	for(int y = 0; y<5;y++)
	{
		for(int x = 0; x<10;x++)
		{
			if(y <=2)
			{
				map[y][x] = 0;
			}
			if(y == 3)
			{
				map[y][x] = 1;
			}
			if(y == 4)
			{
				map[y][x] = 2;
			}
		}
	}
}

bool init()
{
	if(SDL_Init(SDL_INIT_EVERYTHING) == -1 )
	{
		return false;
	}

	screen = SDL_SetVideoMode(640,480,32,SDL_SWSURFACE);

	atexit(SDL_Quit);
	return true;
}

SDL_Surface* LoadBitmap( std::string filename ) 
{
    SDL_Surface* loadedImage = NULL;
    SDL_Surface* optimizedImage = NULL;

	loadedImage = SDL_LoadBMP(filename.c_str());
    
    if( loadedImage != NULL )
    {
        optimizedImage = SDL_DisplayFormat( loadedImage );
        SDL_FreeSurface( loadedImage );
    }

    return optimizedImage;
}




void ApplySurface(int x, int y, SDL_Surface* source, SDL_Surface* destination,SDL_Rect* clip = NULL)
{
	SDL_Rect offset;
    offset.x = x;
    offset.y = y;
    SDL_BlitSurface( source, clip, destination, &offset );
}

void LoadMap(Tile* TileM[5][10])
{
	for(int y = 0; y<5;y++)
	{
		for(int x= 0; x<10;x++)
		{
			switch(map[y][x])
			{
			case 0:
				TileM[y][x] = new Tile(x*TILESIZE,y*TILESIZE,false,0,sky);
				break;
			case 1:
				TileM[y][x] = new Tile(x*TILESIZE,y*TILESIZE,true,1,grass);
				break;
			case 2:
				TileM[y][x] = new Tile(x*TILESIZE,y*TILESIZE,true,2,dirt);
				break;
			}
		}
	}
}

void DrawMap(Tile* TileM[5][10])
{
	for(int y = 0; y<5; y++)
	{
		for(int x = 0; x<10; x++)
		{
			ApplySurface(TileM[y][x]->getBox().x,TileM[y][x]->getBox().y,TileM[y][x]->getImg(),screen);
		}
	}
}

int main(int argc, char** args)
{
	bool quit = false;
	Tile* TileMap[5][10];

	if(!init())
	{
		return  1;
	}

	dirt = LoadBitmap("C:/Dirt.bmp");
	grass = LoadBitmap("C:/Grass.bmp");
	sky = LoadBitmap("C:/Sky.bmp");

	MakeMap();
	LoadMap(TileMap);
	
	while(!quit)
	{
		
		while(SDL_PollEvent(&event ))
        {
            if( event.type == SDL_QUIT )
            {
                quit = true;
            }
        }
		DrawMap(TileMap);
		if( SDL_Flip( screen ) == -1 )
        {
            return 2;    
        }
		
	}
	return 0;
}

Thanks in advance

Arevos · Jul 1st, 2006, 7:02 PM

(Toggle Plain Text)

void DrawMap(Tile* TileM[5][10])

This looks somewhat odd. Shouldn't it be:

(Toggle Plain Text)

void DrawMap(Tile** TileM)

However, C++ has a lot of alternate ways of doing things, so it could be that your function is perfectly valid.

Wizard1988 · Jul 1st, 2006, 7:11 PM

I figured out what I did wrong. It was the declaration of the array.

grumpy · Jul 1st, 2006, 7:18 PM

Care to enlighten further? I'm assuming that the problem is that the dimensions of one of your arrays were in the wrong order ([10][5] when it should have been [5][10]).

Wizard1988 · Jul 1st, 2006, 7:28 PM

Yes the dimensions were in reverse order. At this point I am trying to figure out the best way to store a map so that it would be easy for editing. I will propably rewrite most of the code.

Game_Ender · Jul 2nd, 2006, 5:03 PM

Quote:

Originally Posted by Wizard1988

At this point I am trying to figure out the best way to store a map so that it would be easy for editing.

A simple text format should suit you well. XML is quite trendy now and there are some easy to use and lightweight parsers like TinyXML (which I use extsively) which make working with it a breeze. You could create a file that looked like this:

(Toggle Plain Text)

<!-- Standard XML Header here (I am a comment)-->
<level>
   <!-- Define Values for terrain types -->
   <types>
      <sky>0</sky>
      <grass>1</grass>
      <dirt>2</dirt>
   </types>
   
   <!-- Our actual map data -->
   <tiles width="10" height="5">
      <row>0, 0, 0, 0, 0, 0, 0, 0, 0, 0</row>
      <row>0, 0, 0, 0, 0, 0, 0, 0, 0, 0</row>
      <row>0, 0, 0, 0, 0, 0, 0, 0, 0, 0</row>
      <row>1, 1, 1, 1, 1, 1, 1, 1, 1, 1</row>
      <row>2, 2, 2, 2, 2, 2, 2, 2, 2, 2</row>
   </tiles>
</level>

Now XML is not always the way to go, it can be overly verbose and is considered heavy wieght for many tasks. An advantage is others can easily write tools that work with your formats because they don't have to write a custom parser.

Good luck on you project.

Jul 1st, 2006, 6:18 PM	#1
Wizard1988 Professional Programmer Join Date: Oct 2005 Location: Chitown Posts: 414 Rep Power: 3	Array Problems? I am attempting to write a side scroller using SDL. First I am experimenting with creating a map using two dimensional arrays. The array I am currently using is an integer array or 5 by 10. Value of 0 means that it represents the sky, 1 represents grass, and 2 represents dirt. Here is how the array looks: (Toggle Plain Text) { {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {1,1,1,1,1,1,1,1,1,1}, {2,2,2,2,2,2,2,2,2,2} }; { {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {1,1,1,1,1,1,1,1,1,1}, {2,2,2,2,2,2,2,2,2,2} }; The problem: Somewhere in my code is a bug which throws off the position of the tiles :mad: The grass should be flat across the whole thing. Here is my code: (Toggle Plain Text) #include <SDL.h> #include <iostream> const int TILESIZE = 32; const int LEVELHEIGHT = 15; const int LEVELWIDTH = 100; const int SKY = 0; const int GRASS = 1; const int DIRT = 2; SDL_Surface* screen; SDL_Surface* sky; SDL_Surface* grass; SDL_Surface* dirt; SDL_Event event; int map [10][5]; class Tile { private: int type; bool solid; SDL_Surface* image; SDL_Rect box; public: Tile(int x, int y, bool s, int t, SDL_Surface* img); SDL_Surface* getImg(){return image;} SDL_Rect getBox(){return box;} bool IsSolid(){return solid;} }; Tile::Tile(int x, int y, bool s, int t, SDL_Surface* img) { box.x = x; box.y = y; box.w = TILESIZE; box.h = TILESIZE; solid = s; type = t; image = img; } void MakeMap() { for(int y = 0; y<5;y++) { for(int x = 0; x<10;x++) { if(y <=2) { map[y][x] = 0; } if(y == 3) { map[y][x] = 1; } if(y == 4) { map[y][x] = 2; } } } } bool init() { if(SDL_Init(SDL_INIT_EVERYTHING) == -1 ) { return false; } screen = SDL_SetVideoMode(640,480,32,SDL_SWSURFACE); atexit(SDL_Quit); return true; } SDL_Surface* LoadBitmap( std::string filename ) { SDL_Surface* loadedImage = NULL; SDL_Surface* optimizedImage = NULL; loadedImage = SDL_LoadBMP(filename.c_str()); if( loadedImage != NULL ) { optimizedImage = SDL_DisplayFormat( loadedImage ); SDL_FreeSurface( loadedImage ); } return optimizedImage; } void ApplySurface(int x, int y, SDL_Surface* source, SDL_Surface* destination,SDL_Rect* clip = NULL) { SDL_Rect offset; offset.x = x; offset.y = y; SDL_BlitSurface( source, clip, destination, &offset ); } void LoadMap(Tile* TileM[5][10]) { for(int y = 0; y<5;y++) { for(int x= 0; x<10;x++) { switch(map[y][x]) { case 0: TileM[y][x] = new Tile(xTILESIZE,yTILESIZE,false,0,sky); break; case 1: TileM[y][x] = new Tile(xTILESIZE,yTILESIZE,true,1,grass); break; case 2: TileM[y][x] = new Tile(xTILESIZE,yTILESIZE,true,2,dirt); break; } } } } void DrawMap(Tile* TileM[5][10]) { for(int y = 0; y<5; y++) { for(int x = 0; x<10; x++) { ApplySurface(TileM[y][x]->getBox().x,TileM[y][x]->getBox().y,TileM[y][x]->getImg(),screen); } } } int main(int argc, char** args) { bool quit = false; Tile* TileMap[5][10]; if(!init()) { return 1; } dirt = LoadBitmap("C:/Dirt.bmp"); grass = LoadBitmap("C:/Grass.bmp"); sky = LoadBitmap("C:/Sky.bmp"); MakeMap(); LoadMap(TileMap); while(!quit) { while(SDL_PollEvent(&event )) { if( event.type == SDL_QUIT ) { quit = true; } } DrawMap(TileMap); if( SDL_Flip( screen ) == -1 ) { return 2; } } return 0; } #include <SDL.h> #include <iostream> const int TILESIZE = 32; const int LEVELHEIGHT = 15; const int LEVELWIDTH = 100; const int SKY = 0; const int GRASS = 1; const int DIRT = 2; SDL_Surface* screen; SDL_Surface* sky; SDL_Surface* grass; SDL_Surface* dirt; SDL_Event event; int map [10][5]; class Tile { private: int type; bool solid; SDL_Surface* image; SDL_Rect box; public: Tile(int x, int y, bool s, int t, SDL_Surface* img); SDL_Surface* getImg(){return image;} SDL_Rect getBox(){return box;} bool IsSolid(){return solid;} }; Tile::Tile(int x, int y, bool s, int t, SDL_Surface* img) { box.x = x; box.y = y; box.w = TILESIZE; box.h = TILESIZE; solid = s; type = t; image = img; } void MakeMap() { for(int y = 0; y<5;y++) { for(int x = 0; x<10;x++) { if(y <=2) { map[y][x] = 0; } if(y == 3) { map[y][x] = 1; } if(y == 4) { map[y][x] = 2; } } } } bool init() { if(SDL_Init(SDL_INIT_EVERYTHING) == -1 ) { return false; } screen = SDL_SetVideoMode(640,480,32,SDL_SWSURFACE); atexit(SDL_Quit); return true; } SDL_Surface* LoadBitmap( std::string filename ) { SDL_Surface* loadedImage = NULL; SDL_Surface* optimizedImage = NULL; loadedImage = SDL_LoadBMP(filename.c_str()); if( loadedImage != NULL ) { optimizedImage = SDL_DisplayFormat( loadedImage ); SDL_FreeSurface( loadedImage ); } return optimizedImage; } void ApplySurface(int x, int y, SDL_Surface* source, SDL_Surface* destination,SDL_Rect* clip = NULL) { SDL_Rect offset; offset.x = x; offset.y = y; SDL_BlitSurface( source, clip, destination, &offset ); } void LoadMap(Tile* TileM[5][10]) { for(int y = 0; y<5;y++) { for(int x= 0; x<10;x++) { switch(map[y][x]) { case 0: TileM[y][x] = new Tile(xTILESIZE,yTILESIZE,false,0,sky); break; case 1: TileM[y][x] = new Tile(xTILESIZE,yTILESIZE,true,1,grass); break; case 2: TileM[y][x] = new Tile(xTILESIZE,yTILESIZE,true,2,dirt); break; } } } } void DrawMap(Tile* TileM[5][10]) { for(int y = 0; y<5; y++) { for(int x = 0; x<10; x++) { ApplySurface(TileM[y][x]->getBox().x,TileM[y][x]->getBox().y,TileM[y][x]->getImg(),screen); } } } int main(int argc, char** args) { bool quit = false; Tile* TileMap[5][10]; if(!init()) { return 1; } dirt = LoadBitmap("C:/Dirt.bmp"); grass = LoadBitmap("C:/Grass.bmp"); sky = LoadBitmap("C:/Sky.bmp"); MakeMap(); LoadMap(TileMap); while(!quit) { while(SDL_PollEvent(&event )) { if( event.type == SDL_QUIT ) { quit = true; } } DrawMap(TileMap); if( SDL_Flip( screen ) == -1 ) { return 2; } } return 0; } Thanks in advance

Jul 1st, 2006, 7:02 PM	#2
Arevos Programming Guru Join Date: Aug 2005 Location: England Posts: 1,499 Rep Power: 4	(Toggle Plain Text) void DrawMap(Tile* TileM[5][10]) void DrawMap(Tile* TileM[5][10]) This looks somewhat odd. Shouldn't it be: (Toggle Plain Text) void DrawMap(Tile TileM) void DrawMap(Tile TileM) However, C++ has a lot of alternate ways of doing things, so it could be that your function is perfectly valid.

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Jul 1st, 2006, 7:11 PM	#3
Wizard1988 Professional Programmer Join Date: Oct 2005 Location: Chitown Posts: 414 Rep Power: 3	I figured out what I did wrong. It was the declaration of the array.

Jul 1st, 2006, 7:18 PM	#4
grumpy Programming Guru Join Date: Jun 2005 Location: Adelaide, South Australia Posts: 1,192 Rep Power: 5	Care to enlighten further? I'm assuming that the problem is that the dimensions of one of your arrays were in the wrong order ([10][5] when it should have been [5][10]).

Jul 1st, 2006, 7:28 PM	#5
Wizard1988 Professional Programmer Join Date: Oct 2005 Location: Chitown Posts: 414 Rep Power: 3	Yes the dimensions were in reverse order. At this point I am trying to figure out the best way to store a map so that it would be easy for editing. I will propably rewrite most of the code.

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Programming Forums > Application Development > C++

Array Problems?