/***************************************************************************

  video hardware for Tecmo games

***************************************************************************/

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

unsigned char *tecmo_videoram,*tecmo_colorram;
unsigned char *tecmo_videoram2,*tecmo_colorram2;
unsigned char *tecmo_scroll;
int tecmo_videoram2_size;

static unsigned char *dirtybuffer2;
static struct osd_bitmap *tmpbitmap2,*tmpbitmap3;

static int video_type = 0;
/*
   video_type is used to distinguish Rygar, Silkworm and Gemini Wing.
   This is needed because there is a difference in the tile and sprite indexing.
*/



/***************************************************************************

  Start the video hardware emulation.

***************************************************************************/

int tecmo_vh_start(void)
{
	if (generic_vh_start()) return 1;

	if ((dirtybuffer2 = malloc(videoram_size)) == 0)
	{
		generic_vh_stop();
		return 1;
	}
	memset(dirtybuffer2,1,videoram_size);

	/* the background area is twice as wide as the screen */
	if ((tmpbitmap2 = osd_new_bitmap(2*Machine->drv->screen_width,Machine->drv->screen_height,Machine->scrbitmap->depth)) == 0)
	{
		free(dirtybuffer2);
		generic_vh_stop();
		return 1;
	}
	if ((tmpbitmap3 = osd_new_bitmap(2*Machine->drv->screen_width,Machine->drv->screen_height,Machine->scrbitmap->depth)) == 0)
	{
		osd_free_bitmap(tmpbitmap2);
		free(dirtybuffer2);
		generic_vh_stop();
		return 1;
	}

	/* 0x100 is the background color */
	palette_transparent_color = 0x100;

	return 0;
}

int rygar_vh_start(void)
{
	video_type = 0;
	return tecmo_vh_start();
}

int silkworm_vh_start(void)
{
	video_type = 1;
	return tecmo_vh_start();
}

int gemini_vh_start(void)
{
	video_type = 2;
	return tecmo_vh_start();
}



/***************************************************************************

  Stop the video hardware emulation.

***************************************************************************/
void tecmo_vh_stop(void){
  osd_free_bitmap(tmpbitmap3);
  osd_free_bitmap(tmpbitmap2);
  free(dirtybuffer2);
  generic_vh_stop();
}

void tecmo_videoram_w(int offset,int data)
{
	if (tecmo_videoram[offset] != data)
	{
		dirtybuffer2[offset] = 1;
		tecmo_videoram[offset] = data;
	}
}

void tecmo_colorram_w(int offset,int data)
{
	if (tecmo_colorram[offset] != data)
	{
		dirtybuffer2[offset] = 1;
		tecmo_colorram[offset] = data;
	}
}


/***************************************************************************

  Draw the game screen in the given osd_bitmap.
  Do NOT call osd_update_display() from this function, it will be called by
  the main emulation engine.

***************************************************************************/

void tecmo_draw_sprites( struct osd_bitmap *bitmap, int priority )
{
	int offs;

	/* draw all visible sprites of specified priority */
	for (offs = 0;offs < spriteram_size;offs += 8)
	{
		int flags = spriteram[offs+3];


		if( (flags>>6) == priority )
		{
			int bank = spriteram[offs+0];
			if( bank & 4 )
			{ /* visible */
				int which = spriteram[offs+1];

				int code;
				int size = (spriteram[offs + 2] & 3);
				/* 0 = 8x8 1 = 16x16 2 = 32x32 3 = 64x64 */
				if (size == 3) continue;	/* not used by these games */

				if( video_type != 0)
				  code = (which) + ((bank&0xf8)<<5); /* silkworm */
				else
				  code = (which)+((bank&0xf0)<<4); /* rygar */

				if (size == 1) code >>= 2;
				else if (size == 2) code >>= 4;

				drawgfx(bitmap,Machine->gfx[size+1],
						code,
						flags&0xf, /* color */
						bank&1, /* flipx */
						bank&2, /* flipy */

						spriteram[offs + 5] - ((flags & 0x10) << 4), /* sx */
						spriteram[offs + 4] - ((flags & 0x20) << 3), /* sy */

						&Machine->drv->visible_area,
						priority == 3 ? TRANSPARENCY_THROUGH : TRANSPARENCY_PEN,
						priority == 3 ? palette_transparent_pen : 0);
			}
		}
	}
}

void tecmo_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
{
	int offs;


palette_init_used_colors();

{
	int color,code,i;
	int colmask[16];
	int pal_base;


	pal_base = Machine->drv->gfxdecodeinfo[5].color_codes_start;

	for (color = 0;color < 16;color++) colmask[color] = 0;

	for (offs = videoram_size - 1;offs >= 0;offs--)
	{
		if (video_type == 2)	/* Gemini Wing */
		{
			code = videoram[offs] + 16 * (colorram[offs] & 0x70);
			color = colorram[offs] & 0x0f;
		}
		else
		{
			code = videoram[offs] + 256 * (colorram[offs] & 0x07),
			color = colorram[offs] >> 4;
		}

		colmask[color] |= Machine->gfx[5]->pen_usage[code];
	}

	for (color = 0;color < 16;color++)
	{
		if (colmask[color] & (1 << 0))
			palette_used_colors[pal_base + 16 * color] = PALETTE_COLOR_TRANSPARENT;
		for (i = 1;i < 16;i++)
		{
			if (colmask[color] & (1 << i))
				palette_used_colors[pal_base + 16 * color + i] = PALETTE_COLOR_USED;
		}
	}


	pal_base = Machine->drv->gfxdecodeinfo[4].color_codes_start;

	for (color = 0;color < 16;color++) colmask[color] = 0;

	for (offs = videoram_size - 1;offs >= 0;offs--)
	{
		if (video_type == 2)	/* Gemini Wing */
		{
			code = tecmo_videoram[offs] + 16 * (tecmo_colorram[offs] & 0x70);
			color = tecmo_colorram[offs] & 0x0f;
		}
		else
		{
			code = tecmo_videoram[offs] + 256 * (tecmo_colorram[offs] & 0x07),
			color = tecmo_colorram[offs] >> 4;
		}

		colmask[color] |= Machine->gfx[4]->pen_usage[code];
	}

	for (color = 0;color < 16;color++)
	{
		if (colmask[color] & (1 << 0))
			palette_used_colors[pal_base + 16 * color] = PALETTE_COLOR_TRANSPARENT;
		for (i = 1;i < 16;i++)
		{
			if (colmask[color] & (1 << i))
				palette_used_colors[pal_base + 16 * color + i] = PALETTE_COLOR_USED;
		}
	}


	pal_base = Machine->drv->gfxdecodeinfo[1].color_codes_start;

	for (color = 0;color < 16;color++) colmask[color] = 0;

	for (offs = 0;offs < spriteram_size;offs += 8)
	{
		int flags = spriteram[offs+3];
		int bank = spriteram[offs+0];
		if( bank & 4 )
		{ /* visible */
			int which = spriteram[offs+1];
			int size = (spriteram[offs + 2] & 3);
			/* 0 = 8x8 1 = 16x16 2 = 32x32 3 = 64x64 */
			if (size == 3) continue;	/* not used by these games */


			if( video_type != 0 )
				code = (which) + ((bank&0xf8)<<5); /* silkworm */
			else
				code = (which)+((bank&0xf0)<<4); /* rygar */

			if (size == 1) code >>= 2;
			else if (size == 2) code >>= 4;

			color = flags&0xf;

			colmask[color] |= Machine->gfx[size+1]->pen_usage[code];
		}
	}

	for (color = 0;color < 16;color++)
	{
		if (colmask[color] & (1 << 0))
			palette_used_colors[pal_base + 16 * color] = PALETTE_COLOR_TRANSPARENT;
		for (i = 1;i < 16;i++)
		{
			if (colmask[color] & (1 << i))
				palette_used_colors[pal_base + 16 * color + i] = PALETTE_COLOR_USED;
		}
	}


	pal_base = Machine->drv->gfxdecodeinfo[0].color_codes_start;

	for (color = 0;color < 16;color++) colmask[color] = 0;

	for (offs = tecmo_videoram2_size - 1;offs >= 0;offs--)
	{
		code = tecmo_videoram2[offs] + ((tecmo_colorram2[offs] & 0x03) << 8);
		color = tecmo_colorram2[offs] >> 4;
		colmask[color] |= Machine->gfx[0]->pen_usage[code];
	}

	for (color = 0;color < 16;color++)
	{
		for (i = 1;i < 16;i++)
		{
			if (colmask[color] & (1 << i))
				palette_used_colors[pal_base + 16 * color + i] = PALETTE_COLOR_USED;
		}
	}
}

if (palette_recalc())
{
	memset(dirtybuffer,1,videoram_size);
	memset(dirtybuffer2,1,videoram_size);
}


	/* draw the background. */
	for (offs = videoram_size - 1;offs >= 0;offs--)
	{
		if (dirtybuffer[offs])
		{
			int code,color,sx,sy;

			if (video_type == 2)	/* Gemini Wing */
			{
				code = videoram[offs] + 16 * (colorram[offs] & 0x70);
				color = colorram[offs] & 0x0f;
			}
			else
			{
				code = videoram[offs] + 256 * (colorram[offs] & 0x07),
				color = colorram[offs] >> 4;
			}
			sx = offs % 32;
			sy = offs / 32;

			drawgfx(tmpbitmap2,Machine->gfx[5],
					code,
					color,
					0,0,
					16*sx,16*sy,
					0,TRANSPARENCY_NONE,0);

			dirtybuffer[offs] = 0;
		}

		if (dirtybuffer2[offs])
		{
			int code,color,sx,sy;

			if (video_type == 2)	/* Gemini Wing */
			{
				code = tecmo_videoram[offs] + 16 * (tecmo_colorram[offs] & 0x70);
				color = tecmo_colorram[offs] & 0x0f;
			}
			else
			{
				code = tecmo_videoram[offs] + 256 * (tecmo_colorram[offs] & 0x07),
				color = tecmo_colorram[offs] >> 4;
			}
			sx = offs % 32;
			sy = offs / 32;

			drawgfx(tmpbitmap3,Machine->gfx[4],
					code,
					color,
					0,0,
					16*sx,16*sy,
					0,TRANSPARENCY_NONE,0);
		}
		dirtybuffer2[offs] = 0;
	}


	/* copy the temporary bitmap to the screen */
	{
		int scrollx,scrolly;

		/* draw background tiles */
		scrollx = -tecmo_scroll[3] - 256 * (tecmo_scroll[4] & 1) - 48;
		scrolly = -tecmo_scroll[5];

		copyscrollbitmap(bitmap,tmpbitmap2,1,&scrollx,1,&scrolly,
				&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
		/* sprites will be drawn with TRANSPARENCY_THROUGH and appear behind the background */
		tecmo_draw_sprites( bitmap,3 ); /* this should never draw anything, but just in case... */

		tecmo_draw_sprites( bitmap,2 );

		/* draw foreground tiles */
		scrollx = -tecmo_scroll[0] - 256 * (tecmo_scroll[1] & 1) - 48;
		scrolly = -tecmo_scroll[2];
		copyscrollbitmap(bitmap,tmpbitmap3,1,&scrollx,1,&scrolly,
				&Machine->drv->visible_area,TRANSPARENCY_PEN,palette_transparent_pen);
	}

	tecmo_draw_sprites( bitmap,1 );

	/* draw the frontmost playfield. They are characters, but draw them as sprites */
	for (offs = tecmo_videoram2_size - 1;offs >= 0;offs--)
	{
		int sx = offs % 32;
		int sy = offs / 32;

		drawgfx(bitmap,Machine->gfx[0],
				tecmo_videoram2[offs] + ((tecmo_colorram2[offs] & 0x03) << 8),
				tecmo_colorram2[offs] >> 4,
				0,0,
				8*sx,8*sy,
				&Machine->drv->visible_area,TRANSPARENCY_PEN,0);
	}
	tecmo_draw_sprites( bitmap,0 ); /* frontmost sprites - used? */
}
