 /****************************************************************************
 *                                    *
 * vidhrdw.c                                *
 *                                    *
 * Functions to emulate the video hardware of the machine.        *
 *                                    *
 ****************************************************************************/

#include "driver.h"
#include "vidhrdw/generic.h"

#define SPRITE_X		0
#define SPRITE_NUMBER	   1
#define SPRITE_PALETTE	  2
#define SPRITE_Y		3

extern unsigned char *speedbal_background_videoram;
extern unsigned char *speedbal_foreground_videoram;
extern unsigned char *speedbal_sprites_dataram;

extern size_t speedbal_background_videoram_size;
extern size_t speedbal_foreground_videoram_size;
extern size_t speedbal_sprites_dataram_size;

static unsigned char *bg_dirtybuffer;	  /* background tiles */
static unsigned char *ch_dirtybuffer;	  /* foreground char  */

static struct mame_bitmap *bitmap_bg;   /* background tiles */
static struct mame_bitmap *bitmap_ch;   /* foreground char  */

PALETTE_INIT( speedbal )
{
	int i;
	#define TOTAL_COLORS(gfxn) (Machine->gfx[gfxn]->total_colors * Machine->gfx[gfxn]->color_granularity)
	#define COLOR(gfxn,offs) (colortable[Machine->drv->gfxdecodeinfo[gfxn].color_codes_start + offs])


	for (i = 0;i < Machine->drv->total_colors;i++)
	{
		int bit0,bit1,bit2,r,g,b;


		/* red component */
		bit0 = (*color_prom >> 0) & 0x01;
		bit1 = (*color_prom >> 1) & 0x01;
		bit2 = (*color_prom >> 2) & 0x01;
		r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
		/* green component */
		bit0 = (*color_prom >> 3) & 0x01;
		bit1 = (*color_prom >> 4) & 0x01;
		bit2 = (*color_prom >> 5) & 0x01;
		g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
		/* blue component */
		bit0 = 0;
		bit1 = (*color_prom >> 6) & 0x01;
		bit2 = (*color_prom >> 7) & 0x01;
		b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;

		palette_set_color(i,r,g,b);
		color_prom++;
	}


	/* characters */
	for (i = 0;i < TOTAL_COLORS(0);i++)
		COLOR(0,i) = *(color_prom++) ;

	/* tiles */
	for (i = 0;i < TOTAL_COLORS(1);i++)
		COLOR(1,i) = *(color_prom++) & 0x0f;

	/* sprites */
	for (i = 0;i < TOTAL_COLORS(2);i++)
		COLOR(2,i) = *(color_prom++) & 0x0f;

}


/*************************************
 *                 *
 *      Start-Stop       *
 *                 *
 *************************************/

VIDEO_START( speedbal )
{
	if ((bg_dirtybuffer = auto_malloc (speedbal_background_videoram_size)) == 0)
		return 1;

	if ((ch_dirtybuffer = auto_malloc (speedbal_foreground_videoram_size)) == 0)
		return 1;

	/* foreground bitmap */
	if ((bitmap_ch = auto_bitmap_alloc (Machine->drv->screen_width,Machine->drv->screen_height)) == 0)
		return 1;

	/* background bitmap */
	if ((bitmap_bg = auto_bitmap_alloc (Machine->drv->screen_width*2,Machine->drv->screen_height*2)) == 0)
		return 1;

	memset (ch_dirtybuffer,1,speedbal_foreground_videoram_size / 2);
	memset (bg_dirtybuffer,1,speedbal_background_videoram_size / 2);
	return 0;

}



/*************************************
 *                 *
 *      Foreground characters RAM    *
 *                 *
 *************************************/

WRITE8_HANDLER( speedbal_foreground_videoram_w )
{
   ch_dirtybuffer[offset] = 1;
   speedbal_foreground_videoram[offset]=data;
}

READ8_HANDLER( speedbal_foreground_videoram_r )
{
   return speedbal_foreground_videoram[offset];
}



/*************************************
 *                 *
 *  Background tiles RAM       *
 *                 *
 *************************************/

WRITE8_HANDLER( speedbal_background_videoram_w )
{
   bg_dirtybuffer[offset] = 1;
   speedbal_background_videoram[offset] = data;
}

READ8_HANDLER( speedbal_background_videoram_r )
{
   return speedbal_background_videoram[offset];
}




/*************************************
 *                 *
 *   Sprite drawing     *
 *                 *
 *************************************/

void speedbal_draw_sprites (struct mame_bitmap *bitmap)
{
	int SPTX,SPTY,SPTTile,SPTColor,offset,f;
	unsigned char carac;
	unsigned char *SPTRegs;

	/* Drawing sprites: 64 in total */

	for (offset = 0;offset < speedbal_sprites_dataram_size;offset += 4)
	{
		SPTRegs = &speedbal_sprites_dataram[offset];


		SPTX = 243 - SPTRegs[SPRITE_Y];
		SPTY = 239 - SPTRegs[SPRITE_X];

		carac  =  SPTRegs[SPRITE_NUMBER ];
		SPTTile=0;
		for (f=0;f<8;f++) SPTTile+= ((carac >>f)&1)<<(7-f);
		SPTColor = (SPTRegs[SPRITE_PALETTE]&0x0f);

		if (!(SPTRegs[SPRITE_PALETTE]&0x40)) SPTTile+=256;

		drawgfx (bitmap,Machine->gfx[2],
				SPTTile,
				SPTColor,
				0,0,
				SPTX,SPTY,
				&Machine->visible_area,TRANSPARENCY_PEN,0);
	}
}



/*************************************
 *                 *
 *     Background drawing: Tiles     *
 *                 *
 *************************************/

void speedbal_draw_background (struct mame_bitmap *bitmap)
{
	int sx,sy,code,tile,offset,color;

	for (offset = 0;offset < speedbal_background_videoram_size ;offset+=2)
	{
	    if (bg_dirtybuffer[offset])
		{
			bg_dirtybuffer[offset] = 0;

			tile = speedbal_background_videoram[offset+0];
			code = speedbal_background_videoram[offset+1];
			tile += (code & 0x30) << 4;
			color=(code&0x0f);

			sx = 15 - (offset / 2) / 16;
			sy = (offset / 2) % 16;

			drawgfx (bitmap_bg,Machine->gfx[1],
					tile,
					color,
					0,0,
					16*sx,16*sy,
					0,TRANSPARENCY_NONE,0);
		}
	}

	copybitmap (bitmap,bitmap_bg,0,0,0,0,&Machine->visible_area,TRANSPARENCY_NONE,0);
}


/*************************************
 *                 *
 *   Foreground drawing: 8x8 graphs  *
 *                 *
 *************************************/

void speedbal_draw_foreground1 (struct mame_bitmap *bitmap)
{
	int sx,sy,code,caracter,color,offset;

	for (offset = 0;offset < speedbal_foreground_videoram_size ;offset+=2)
	{
//      if (ch_dirtybuffer[offset])
		{
			caracter = speedbal_foreground_videoram[offset];
			code     = speedbal_foreground_videoram[offset+1];
			caracter += (code & 0x30) << 4;

			color=(code&0x0f);

			sx = 31 - (offset / 2) / 32;
			sy = (offset / 2) % 32;

			drawgfx (bitmap,Machine->gfx[0],
					caracter,
					color,
					0,0,
					8*sx,8*sy,
					&Machine->visible_area,TRANSPARENCY_PEN,0);

			ch_dirtybuffer[offset] = 0;
		}

	}
}


/*************************************
 *                 *
 *   Refresh   screen     *
 *                 *
 *************************************/

VIDEO_UPDATE( speedbal )
{
	// first background
	speedbal_draw_background (bitmap);

	// second characters (general)
	speedbal_draw_foreground1 (bitmap);

	// thirth sprites
	speedbal_draw_sprites (bitmap);
}
