gsword.c

这个是延伸mame的在wince平台下的游戏模拟器的代码

/***************************************************************************
  Great Swordsman

  Functions to emulate the video hardware of the machine.

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

#include "driver.h"

unsigned int gs_videoram_size;
unsigned int gs_spritexy_size;

unsigned char *gs_videoram;
unsigned char *gs_scrolly_ram;
unsigned char *gs_spritexy_ram;
unsigned char *gs_spritetile_ram;
unsigned char *gs_spriteattrib_ram;

static struct osd_bitmap 	*bitmap_bg;
static unsigned char 	 	*dirtybuffer;
static int 			video_attributes=0;
static int 			flipscreen=0;


void gsword_vh_convert_color_prom(unsigned char *palette, unsigned short *colortable,const unsigned char *color_prom)
{
	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;


		/* red component */
		bit0 = (color_prom[Machine->drv->total_colors] >> 0) & 1;
		bit1 = (color_prom[Machine->drv->total_colors] >> 1) & 1;
		bit2 = (color_prom[Machine->drv->total_colors] >> 2) & 1;
		*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
		/* green component */
		bit0 = (color_prom[Machine->drv->total_colors] >> 3) & 1;
		bit1 = (color_prom[0] >> 0) & 1;
		bit2 = (color_prom[0] >> 1) & 1;
		*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
		/* blue component */
		bit0 = 0;
		bit1 = (color_prom[0] >> 2) & 1;
		bit2 = (color_prom[0] >> 3) & 1;
		*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;

		color_prom++;
	}

	color_prom += Machine->drv->total_colors;
	/* color_prom now points to the beginning of the sprite lookup table */

	for (i = 0;i < TOTAL_COLORS(0);i++)
		COLOR(0,i) = i;

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


int gsword_vh_start(void)
{
	if ((dirtybuffer = malloc(gs_videoram_size)) == 0) return 1;
	if ((bitmap_bg = osd_create_bitmap(Machine->drv->screen_width,2*Machine->drv->screen_height)) == 0)
	{
		free(dirtybuffer);
		return 1;
	}
	memset(dirtybuffer,1,gs_videoram_size);
	return 0;
}

void gsword_vh_stop(void)
{
	free(dirtybuffer);
	osd_free_bitmap(bitmap_bg);
}

void gs_video_attributes_w(int offset, int data)
{
	unsigned char *RAM = Machine->memory_region[Machine->drv->cpu[0].memory_region];

	if (data != video_attributes)
	{
		memset(dirtybuffer,1,gs_videoram_size);
		video_attributes = data;
	}
	RAM[0xa980] = data;
}

void gs_flipscreen_w(int offset, int data)
{
	unsigned char *RAM = Machine->memory_region[Machine->drv->cpu[0].memory_region];

	if (data != flipscreen)
	{
	        memset(dirtybuffer,1,gs_videoram_size);
		flipscreen = data;
	}
	RAM[0x9835] = data;
}

void gs_videoram_w(int offset,int data)
{
	if (gs_videoram[offset] != data)
	{
		dirtybuffer[offset] = 1;
		gs_videoram[offset] = data;
	}
}

void render_background(struct osd_bitmap *bitmap)
{
	int offs;


	/* for every character in the Video RAM, check if it has been modified */
	/* since last time and update it accordingly. */
	for (offs = 0; offs < gs_videoram_size ;offs++)
	{
		if (dirtybuffer[offs])
		{
			int sx,sy,tile,flipx,flipy;


			dirtybuffer[offs] = 0;

			sx = offs % 32;
			sy = offs / 32;
			flipx = 0;
			flipy = 0;

			if (flipscreen)
			{
				flipx = !flipx;
				flipy = !flipy;
			}

			tile = gs_videoram[offs] + ((video_attributes & 0x03) << 8);
			drawgfx(bitmap_bg,Machine->gfx[0],
					tile,
					(tile & 0x3c0) >> 6,	/* ?? */
					flipx,flipy,
					8*sx,8*sy,
					0,TRANSPARENCY_NONE,0);
		}
	}
}


void render_sprites(struct osd_bitmap *bitmap)
{
	int offs;

	for (offs = 0; offs < gs_spritexy_size - 1; offs+=2)
	{
		int sx,sy,flipx,flipy,spritebank,tile;

		if (gs_spritexy_ram[offs]!=0xf1)
		{
			spritebank = 0;
			tile = gs_spritetile_ram[offs];
			sy = 241-gs_spritexy_ram[offs];
			sx = gs_spritexy_ram[offs+1]-56;
			flipx = gs_spriteattrib_ram[offs] & 0x02;
			flipy = gs_spriteattrib_ram[offs] & 0x01;

			if (sx<0) sx+=256;

			if (tile > 127)
			{
				spritebank = 1;
				tile -= 128;
				sy-=16;
			}
			if (flipscreen)
			{
				flipx = !flipx;
				flipy = !flipy;
			}

			drawgfx(bitmap,Machine->gfx[1+spritebank],
					tile,
					gs_spritetile_ram[offs+1] & 0x3f,	/* ?? */
					flipx,flipy,
					sx,sy,
					&Machine->drv->visible_area,TRANSPARENCY_PEN,0);
		}
	}
}


void gsword_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
{
	int scrollx=0,scrolly;

	render_background(bitmap_bg);
	scrolly = -(*gs_scrolly_ram);
	copyscrollbitmap(bitmap,bitmap_bg,1,&scrollx,1,&scrolly,&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
	render_sprites(bitmap);
}