#define SCREEN_WIDTH 320
#include	"sprite.h"

// Sprite constructor
// Allocates memory for NUM_SPRITES sprite structures
Sprite::Sprite(int num_sprites,int w,int h)
{
	image=new unsigned char far *[num_sprites];
	width=w;
	height=h;
	savebuffer=new unsigned char[width*height];
	nsprit = num_sprites;
		// initialize pointers
	for(int ii=0; ii < nsprit;ii++)
		image[ii] = 0;
}

Sprite::~Sprite()
{
	for(int ii=0; ii < nsprit;ii++)
	{
		if(image[ii])
			delete[] image[ii];
	}
	delete[] savebuffer;
	delete[] image;
}


// "Grab" a rectangular sprite image from a 64K bitmap
//  and store in SPRITE[SPRITE_NUM]
void Sprite::grabSprite(unsigned char far *src320_200,int sprite_num,int x1,int y1)
{

	// Allocate memory for sprite bitmap and background
	//  save buffer:
	image[sprite_num]=new unsigned char[width*height];

	// Check if sprite runs past edge of bitmap buffer;
	//  abort if so:

	if ((x1+width>SCREEN_WIDTH) || (y1+height>SCREEN_WIDTH))
			return;

	// Loop through rows and columns of sprite,
	//  storing pixels in sprite buffer:

	for(int row=0; row<height; row++)
		for(int column=0; column<width; column++)
			image[sprite_num][row*width+column]=
				src320_200[(y1+row)*SCREEN_WIDTH+x1+column];
}

// Draw sprite on screen with upper lefthand corner at
// coordinates x,y. Zero pixels are treated as transparent;
// i.e. they are not drawn.
void Sprite::putSprite(int sprite_num,int x,int y,unsigned char far *screen)
{
	int poffset=y*320+x; // Calculate vidram offset of sprite
											 //  coordinates
	int soffset=0;

	// Loop through rows of sprite, transferring nonzero
	//  pixels to screen:

	for(int row=0; row<height; row++) {
		for(int column=0; column<width; column++) {

			// Copy background pixel into background save buffer:

			savebuffer[soffset]=screen[poffset];

			// Get next pixel from sprite image buffer:

			int pixel=image[sprite_num][soffset++];

			// If not transparent, place in in the screen buffer:

			if (pixel) screen[poffset] = pixel;
			poffset++;
		}
		poffset+=(320-width);
	}

	// Record current coordinates of sprite:

	xsprite = x;
	ysprite = y;
}


// Erase sprite from screen by copying saved background
//  image on top of it
void Sprite::eraseSprite(unsigned char far *screen)
{

	// Calculate video memory offset of sprite:

	int voffset=ysprite*320+xsprite;
	int soffset=0;

	// Loop through rows and columns of background save
	// buffer, transferring pixels to screen buffer:

	for(int column=0; column<width; column++) {
		for(int row=0; row<height; row++)
			screen[voffset++]=savebuffer[soffset++];
		voffset+=(320-width); // Position pointer to next line
	}
}