dec0.c

这个是延伸mame的在wince平台下的游戏模拟器的代码

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

  Dec0 Video emulation - Bryan McPhail, [e-mail]

*********************************************************************
	Sprite data:  The unknown bits seem to be unused.

	Byte 0:
		Bit 0 : Y co-ord hi bit
		Bit 1,2: ?
		Bit 3,4 : Sprite height (1x, 2x, 4x, 8x)
		Bit 5  - X flip
		Bit 6  - Y flip
		Bit 7  - Only display Sprite if set
	Byte 1: Y-coords
	Byte 2:
		Bit 0,1,2,3: Hi bits of sprite number
		Bit 4,5,6,7: (Probably unused MSB's of sprite)
	Byte 3: Low bits of sprite number
	Byte 4:
		Bit 0 : X co-ords hi bit
		Bit 1,2: ??
		Bit 3: Sprite flash (sprite is displayed every other frame)
		Bit 4,5,6,7:  - Colour
	Byte 5: X-coords

**********************************************************************

  Palette data

    0x000 - character palettes (Sprites on Midnight R)
    0x200 - sprite palettes (Characters on Midnight R)
    0x400 - tiles 1
  	0x600 - tiles 2

	  Bad Dudes, Robocop, Heavy Barrel, Hippodrome - 24 bit rgb
 		Sly Spy, Midnight Resistance - 12 bit rgb

  Tile data

  	4 bit palette select, 12 bit tile select

**********************************************************************

 Playfield 1 - 8*8 tiles
 Playfield 2 - 16*16 tiles
 Playfield 3 - 16*16 tiles

 Playfield control registers:
   bank 0:
   0: mostly unknown (82, 86, 8e...)
		bit 3 (0x4) set enables rowscroll (true for all games)
		bit 4 (0x8) set _disables_ colscroll!??! (see Heavy Barrel pf3)
		bit 8 (0x80) set in playfield 1 is reverse screen (set via dip-switch)
		bit 8 (0x80) in other playfields unknown
   2: unknown (00 in bg, 03 in fg+text - maybe controls pf transparency?)
   4: unknown (always 00)
   6: playfield shape: 00 = 4x1, 01 = 2x2, 02 = 1x4

   bank 1:
   0: horizontal scroll
   2: vertical scroll
   4: unknown (08 in Hippodrome, 05 in HB, 00 in the others)  (colscroll style?)
   6: Style of rowscroll (maybe only low 3 bits) (see below)

Rowscroll style - bank 1 register 6:
	0: 256 scroll registers (Robocop)
	1: 128?
	2: 64?
	3: 32 scroll registers (Heavy Barrel, Midres)
	4: 16 scroll registers (Bad Dudes, Sly Spy)
	5: 8? (Hippodrome)
	6: 4 scroll registers (Heavy Barrel)
	7: 2 scroll registers (Heavy Barrel, used on other games but registers kept at 0)

Priority:
	Bit 0 set = Playfield 3 drawn over Playfield 2
			~ = Playfield 2 drawn over Playfield 3
	Bit 1 set = Sprites are drawn inbetween playfields
			~ = Sprites are on top of playfields
	Bit 2
	Bit 3 set = ...


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

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

#define TEXTRAM_SIZE	0x2000	/* Size of text layer */
#define TILERAM_SIZE	0x800	/* Size of background and foreground */


/* Video */
unsigned char *dec0_pf1_data,*dec0_pf2_data,*dec0_pf3_data;
static unsigned char *dec0_pf1_dirty,*dec0_pf3_dirty,*dec0_pf2_dirty;
static struct osd_bitmap *dec0_pf1_bitmap;
static int dec0_pf1_current_shape;
static struct osd_bitmap *dec0_pf2_bitmap;
static int dec0_pf2_current_shape;
static struct osd_bitmap *dec0_pf3_bitmap;
static int dec0_pf3_current_shape;

unsigned char *dec0_pf1_rowscroll,*dec0_pf2_rowscroll,*dec0_pf3_rowscroll;
unsigned char *dec0_pf1_colscroll,*dec0_pf2_colscroll,*dec0_pf3_colscroll;
static unsigned char dec0_pf1_control_0[8];
static unsigned char dec0_pf1_control_1[8];
static unsigned char dec0_pf2_control_0[8];
static unsigned char dec0_pf2_control_1[8];
static unsigned char dec0_pf3_control_0[8];
static unsigned char dec0_pf3_control_1[8];

static int dec0_pri;

/* Prototypes for this file */
void dec0_vh_stop (void);

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

static void update_24bitcol(int offset)
{
	int r,g,b;

	r = (READ_WORD(&paletteram[offset]) >> 0) & 0xff;
	g = (READ_WORD(&paletteram[offset]) >> 8) & 0xff;
	b = (READ_WORD(&paletteram_2[offset]) >> 0) & 0xff;

	palette_change_color(offset / 2,r,g,b);
}

void dec0_paletteram_w_rg(int offset,int data)
{
	COMBINE_WORD_MEM(&paletteram[offset],data);
	update_24bitcol(offset);
}

void dec0_paletteram_w_b(int offset,int data)
{
	COMBINE_WORD_MEM(&paletteram_2[offset],data);
	update_24bitcol(offset);
}

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

/* pf23priority: 1 -> pf2 transparent, pf3 not transparent */
/*               0 -> pf2 not transparent, pf3 transparent */
static void dec0_update_palette(int pf23priority)
{
	int offs;
	int color,code,i;
	int colmask[16];
	int pal_base;

	memset(palette_used_colors,PALETTE_COLOR_UNUSED,Machine->drv->total_colors * sizeof(unsigned char));

	pal_base = Machine->drv->gfxdecodeinfo[0].color_codes_start;
	for (color = 0;color < 16;color++) colmask[color] = 0;
	for (offs = 0; offs < TEXTRAM_SIZE;offs += 2)
	{
		code = READ_WORD(&dec0_pf1_data[offs]);
		color = (code & 0xf000) >> 12;
		code &= 0x0fff;
		colmask[color] |= Machine->gfx[0]->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 < TILERAM_SIZE;offs += 2)
	{
		code = READ_WORD(&dec0_pf2_data[offs]);
		color = (code & 0xf000) >> 12;
		code &= 0x0fff;
		colmask[color] |= Machine->gfx[1]->pen_usage[code];
	}

	for (color = 0;color < 16;color++)
	{
		if (colmask[color] & (1 << 0))
			palette_used_colors[pal_base + 16 * color] = pf23priority ? PALETTE_COLOR_USED : 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[2].color_codes_start;
	for (color = 0;color < 16;color++) colmask[color] = 0;
	for (offs = 0; offs < TILERAM_SIZE;offs += 2)
	{
		code = READ_WORD(&dec0_pf3_data[offs]);
		color = (code & 0xf000) >> 12;
		code &= 0x0fff;
		colmask[color] |= Machine->gfx[2]->pen_usage[code];
	}

	for (color = 0;color < 16;color++)
	{
		if (colmask[color] & (1 << 0))
			palette_used_colors[pal_base + 16 * color] = pf23priority ? PALETTE_COLOR_TRANSPARENT : PALETTE_COLOR_USED;
		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[3].color_codes_start;
	for (color = 0;color < 16;color++) colmask[color] = 0;
	for (offs = 0;offs < 0x800;offs += 8)
	{
		int x,y,sprite,multi;

		y = READ_WORD(&spriteram[offs]);
		if ((y&0x8000) == 0) continue;

		x = READ_WORD(&spriteram[offs+4]);
		color = (x & 0xf000) >> 12;

		multi = (1 << ((y & 0x1800) >> 11)) - 1;	/* 1x, 2x, 4x, 8x height */
											/* multi = 0   1   3   7 */

		x = x & 0x01ff;
		if (x >= 256) x -= 512;
		x = 240 - x;
		if (x>256) continue; /* Speedup + save colours */

		sprite = READ_WORD (&spriteram[offs+2]) & 0x0fff;

		sprite &= ~multi;

		while (multi >= 0)
		{
			colmask[color] |= Machine->gfx[3]->pen_usage[sprite + multi];

			multi--;
		}
	}

	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(dec0_pf1_dirty,1,TEXTRAM_SIZE);
		memset(dec0_pf2_dirty,1,TILERAM_SIZE);
		memset(dec0_pf3_dirty,1,TILERAM_SIZE);
	}
}

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

static void dec0_drawsprites(struct osd_bitmap *bitmap,int pri_mask,int pri_val)
{
	int offs;
	static int flash_counter;
	flash_counter++;

	for (offs = 0;offs < 0x800;offs += 8)
	{
		int x,y,sprite,colour,multi,fx,fy,inc,flash;

		y = READ_WORD(&spriteram[offs]);
		if ((y&0x8000) == 0) continue;

		x = READ_WORD(&spriteram[offs+4]);
		colour = x >> 12;
		if ((colour & pri_mask) != pri_val) continue;

		flash=x&0x800;
		if (flash && flash_counter%2) continue;

		fx = y & 0x2000;
		fy = y & 0x4000;
		multi = (1 << ((y & 0x1800) >> 11)) - 1;	/* 1x, 2x, 4x, 8x height */
											/* multi = 0   1   3   7 */

		sprite = READ_WORD (&spriteram[offs+2]) & 0x0fff;

		x = x & 0x01ff;
		y = y & 0x01ff;
		if (x >= 256) x -= 512;
		if (y >= 256) y -= 512;
		x = 240 - x;
		y = 240 - y;

		if (x>256) continue; /* Speedup */

		sprite &= ~multi;
		if (fy)
			inc = -1;
		else
		{
			sprite += multi;
			inc = 1;
		}

		while (multi >= 0)
		{
			drawgfx(bitmap,Machine->gfx[3],
					sprite - multi * inc,
					colour,
					fx,fy,
					x,y - 16 * multi,
					&Machine->drv->visible_area,TRANSPARENCY_PEN,0);

			multi--;
		}
	}
}

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

static void dec0_pf1_update(void)
{
	int offs,mx,my,color,tile,quarter;
	int offsetx[4],offsety[4];

	switch (READ_WORD(&dec0_pf1_control_0[6]))
	{
		case 0:	/* 4x1 */
			offsetx[0] = 0;
			offsetx[1] = 256;
			offsetx[2] = 512;
			offsetx[3] = 768;
			offsety[0] = 0;
			offsety[1] = 0;
			offsety[2] = 0;
			offsety[3] = 0;
			if (dec0_pf1_current_shape != 0)
			{
				osd_free_bitmap(dec0_pf1_bitmap);
				dec0_pf1_bitmap = osd_create_bitmap(1024,256);
				dec0_pf1_current_shape = 0;
				memset(dec0_pf1_dirty,1,TEXTRAM_SIZE);
			}
			break;
		case 1:	/* 2x2 */
			offsetx[0] = 0;
			offsetx[1] = 0;
			offsetx[2] = 256;
			offsetx[3] = 256;
			offsety[0] = 0;
			offsety[1] = 256;
			offsety[2] = 0;
			offsety[3] = 256;
			if (dec0_pf1_current_shape != 1)
			{
				osd_free_bitmap(dec0_pf1_bitmap);
				dec0_pf1_bitmap = osd_create_bitmap(512,512);
				dec0_pf1_current_shape = 1;
				memset(dec0_pf1_dirty,1,TEXTRAM_SIZE);
			}
			break;
		case 2:	/* 1x4 */
			offsetx[0] = 0;
			offsetx[1] = 0;
			offsetx[2] = 0;
			offsetx[3] = 0;
			offsety[0] = 0;
			offsety[1] = 256;
			offsety[2] = 512;
			offsety[3] = 768;
			if (dec0_pf1_current_shape != 2)
			{
				osd_free_bitmap(dec0_pf1_bitmap);
				dec0_pf1_bitmap = osd_create_bitmap(256,1024);
				dec0_pf1_current_shape = 2;
				memset(dec0_pf1_dirty,1,TEXTRAM_SIZE);
			}
			break;